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A464 Human Tissue Biology Laboratory Guide Spring 2015 Anthony L. Mescher, Ph.D. Emeritus Professor of Anatomy and Cell Biology Indiana University School of Medicine Bloomington TABLE OF CONTENTS Preface Useful Greek and Latin Roots Glossary Laboratory Guide Introduction to Light Microscopy and Electron Micrographs Cell Structure and Function Cell Division and Cell Death Epithelia Secretory Epithelia and Glands Extracellular Matrix and Types of Connective Tissue Muscle Blood Cells and Hemopoiesis Circulatory System Immune (Lymphoid) System Skin Cartilage and Bone Bone Formation Teeth and Tooth Formation Central Nervous System Peripheral Nerves Sensory Receptors The Eye Gastrointestinal Tract (Part 1) Gastrointestinal Tract (Part 2) Digestive Glands and Liver Respiratory System Urinary System Endocrine System Male Reproductive System Female Reproductive System Instructions for the Use of the Nikon Alphaphot 2 Microscope PREFACE Our course in Human Tissue Biology at I.U. covers features of the differentiated cells and tissues that make up the body. The main goal of the course is to better understand how structure and function are integrated in the molecules, cells, tissues, and organs of the body. A major theme of the lectures and the focus of the laboratory studies is the area of histology, the branch of biology that centers on the cells and tissues within an organism and which, as such, serves as the foundation for other aspects of anatomy and physiology. The histological treatment of various tissues and organs will often be supplemented in lecture with material more related to other aspects of the subject, such as recent work on the tissue’s development or discussions of the tissue’s structure or function that are medically important. This Laboratory Guide for A464, Human Tissue Biology, is designed to be used with the book Junqueira’s Basic Histology, 12th edition, which contains most of the required reading and laboratory material to be studied in this course. An electronic version of the lab guide and the slide collection with digitized slides are available at http://medsci.indiana.edu/a464/start.html The Glossary of histological terms included here is from Introduction to Functional Histology by I.R. Telford and C.F. Bridgman. Each laboratory exercise in the Laboratory Guide is designed to occupy approximately two hours of study for thorough understanding of the material, although some exercises require more time than others. The guide for each lab session begins with a short list of objectives your efforts are supposed to achieve. Always read these objectives carefully and make sure you have completed each successfully before leaving the lab. Figures from Junqueira are referred to continuously in every lab session and therefore the exercises MUST be undertaken with a copy of Junqueira’s edition in front of you along with the microscope. Please remember to bring that book along to class every day. Although the prepared student will come to class having read the material to be covered that day, you should also read the captions to the figures in Junqueira again while studying the slides and identifying the cells and other components listed in the Laboratory Guide. This will greatly improve your understanding of the tissue’s functions. To help you further improve your understanding of each histological topic, I have placed questions in each lab exercise, with place for you to provide answers. Doing this will help insure that you meet the Learning Objectives for the exercise. Lab exams will be designed to determine how well you have met the objectives listed with each lab exercise. You will be expected to recognize and know the basic information on the structures listed with the electron micrographs and slide(s) assigned for study in each exercise. Students in histology labs find that it is sometimes helpful to draw or sketch the appearance of certain microscopic structures, such as the arrangement of cells in a specific tissue or part of an organ. We have placed an extra page with each laboratory exercise in the Guide to allow plenty of space for notes and drawings. Taking the time to sketch and label the parts of the more complex tissues we will study during the semester will almost certainly improve your recognition and understanding of the structures. To help you further in studying the material, we have also included with most of the laboratory exercises unlabeled drawings of structures with names of important components to be identified on the drawing and on your specimens. The guides for the laboratory exercises in the course were written with help from the individuals who have taught the labs in recent years, and I gratefully acknowledge their help. Thanks are also due to Sue Childress for her work maintaining and steadily improving the microscope slide collections. Anthony L. Mescher Introduction to Light Microscopy and Electron Micrographs Various types of light and electron microscopes are the most important tools used for the study of cells and tissues. Not only do these instruments provide the foundation of tissue biology or histology, light microscopes are also the principal tool for pathologists, hematologists, and certain other medical professionals. For effective learning in Tissue Biology you must become proficient in the use of the basic bright-field light microscope, techniques associated with its use, and in the study and interpretation of transmission and scanning images produced by electron microscopes. Objectives v Learn the correct use and care of the light microscope, LM v Understand the histological techniques used in preparing tissue samples for light and transmission electron microscopy, TEM v Understand the fundamentals of biological staining and the ways in which common stains are used to provide more information about cells v Begin learning to interpret images of cells and tissues seen with either the LM or EMs. The Light Microscope The major tool used in this laboratory will be the light microscope. Our microscopes are high-quality binocular microscopes made by Nikon. A copy of the “owner’s manual” for your microscope is included at the end of this Laboratory Guide. Read the Handling Precautions and other sections of this manual and use the photographs to identify the various parts of the microscope and learn their functions. Very few adjustments to the scope will be required during its day-to-day use. Proper focusing, proper adjustment of the eyepieces, and proper illumination are all important for comfortable and effective use of the scope. For proper illumination of the slide, adjust your microscope as follows: 1. 2. 3. 4. 5. 6. 7. 8. Plug the microscope into the outlet on the front of your table and turn on the light. Place any slide from your collection on the stage and clip it into place. Swing in the low-power 10X objective and focus on the specimen. Adjust the brightness of the light to a fairly bright, but comfortable level. Locate the condenser diaphragm below the stage and open it fully. Swing in the high-power 40X objective. Turn the condenser focus knob slightly, focusing it until maximum illumination is obtained (usually the condenser is in the highest position.) Slowly close the condenser diaphragm until you detect a slight darkening of the field. Do not use the condenser diaphragm to control the amount of light since this will introduce aberrations into the image. Control the amount of light with the brightness control dial/power switch. Check the “owner’s manual” at the end of this Lab Guide for further information about your light microscope. Make certain that you can use your microscope correctly and are familiar with its operation before leaving the first laboratory period. If the eyepieces or objectives need cleaning use lens paper (NOT paper towels or Kimwipes which can scratch lenses). Never remove the lenses from the microscope for any reason. To avoid losing slides, always remember to return the slide to your collection before turning off the microscope. After using the microscope, rewind the cord on its holder and cover it. Always use both hands when carrying the microscope and be very careful not to bang or hit any projecting part of the scope on the sides of the locker when removing or replacing the scope in its locker. THE MICROSCOPES ARE NEVER TO LEAVE THE LAB, JORDAN 001. Tissue Preparation and Stains Details of the methods and techniques used to prepare tissues for histological study and the chemistry of biological stains are extensive subjects and are beyond the scope of the course. However, a basic understanding of tissue preparation for light microscopy and staining mechanisms is essential to understand and interpret the images you will see with your microscope. Very briefly, the steps involved in tissue and slide preparation are as follows: 1. 2. 3. 4. 5. 6. 7. Tissue removal, trimming and sampling. Fixation in an aqueous preservative solution. Dehydration (replacing the water with alcohol.) Clearing (replacing the alcohol with another solvent miscible with paraffin.) Embedding (in paraffin for LM or in “plastics” for TEM.) Sectioning on a microtome with steel or glass knives. Staining (with dyes for LM or electron-opaque compounds for TEM.) Most routine histological stains involve a combination of basic and acidic dyes/stains. Basic stains such as hematoxylin contain positive charges (are cationic) and binds to negatively charged substances. Such substances are said to be “basophilic.” Acidic stains such as eosin contain negative charges (are anionic) and binds to positively charged substances in tissues. Such substances are said to be “acidophilic” or “eosinophilic.” The hematoxylin and eosin combination, a stain and a “counter stain,” is the most widely used staining method for routine histology and most of the slides in your collection are H&E stained. Hematoxylin binds cellular structures containing nucleic acid, such as the nucleus and RNA-rich organelles, usually staining them a shade of dark blue or purple. The acidic counter stain eosin binds proteins with many cationic groups, which includes many cytoplasmic proteins and collagen outside the cells, staining this material pinkish or orange. Most of the light micrographs in Junqueira show examples of tissues stained with hematoxylin and eosin (H&E). Examine any three (3) slides of different tissues in your collection and in each locate basophilic structures, such as cell nuclei, and eosinophilic structures, such as collagen bundles and structures in cytoplasm. Interpretation of Microscopic Structures While examining sections with the microscope it is important to keep in mind that the two-dimensional images you are seeing are actually sections of three-dimensional structures. By studying the structures cut in different planes one can mentally reconstruct their three dimensional appearance and interpret their shape accurately. Examine the diagrams shown here and note the various appearances of structures when cut through different planes. After studying the diagrams, examine an actual specimen such as the kidney section (slides 64 or 66) which includes many tubes in many different orientations. Identify such tubular structures cut transversely, longitudinally, and obliquely. You must also be aware of common artifacts frequently encountered in tissue sections prepared for LM. Such artifacts are due to minor problems in the slide preparation technique and must not be interpreted as real features in the tissue. If a “structure” is not shown in the atlas’ depiction of a certain tissue, it may actually be an artifact unique to your slide. The types of artifacts listed below are particularly common and some are likely to be present on some slides in your collection. Wrinkles, folds, and knife scratches are especially hard to avoid completely and you should expect to find these artifacts occasionally during the course. 1. 2. 3. 4. 5. Notes Wrinkles or folds in the section: well-defined very dense staining areas where detail is obscured. Knife marks on the section: usually straight cuts, fine lines, or “scuff marks” across a section caused by nicks or dull spots on the cutting edge of the microtome blade. Poor fixation (postmortem degeneration): the tissue stains poorly and shows poor microscopic detail in some areas but not others Tissue shrinkage: components in the section are separated from each other giving rise to irregular empty spaces, most often between different tissue components or regions. Precipitates from the stain: usually appear as small black particles scattered across some regions of the section. Cellular Organelles’ Structure and Function While looking at the slides listed below, study the appropriate diagrams and electron micrographs (EMs) in Junqueira. Compare the very high magnification “ultrastructural” EM appearance of organelles and other structures with their appearance in Junqueira’s LM photographs and in the cells on your slides. The EMs and other figures in Junqueira are an important part of today’s lab. They will help you understand and interpret all other EMs you will see later in the later labs. Carefully read the text accompanying each figure as you study it. Identify the basic structural features that characterize each and every example you will see of each organelle. Objectives v Gain experience in the ability to correlate two-dimensional images of organelles in both the light microscope LM and transmission electron micrograph TEM with their actual three-dimensional structure v Recognize the important cytoplasmic organelles in both light microscopes and electron micrographs Micrographs and diagrams - Fig 2-1, 2-2, 2-3 o Plasma Membrane In the fluid mosaic model for membrane structure, what is “fluid” and why? - Fig 3-2 o Nucleus o Heterochromatin o Euchromatin o Nucleolus - Fig 3-5, 3-6 o Nuclear Envelope o Nuclear Pore Fig 2-16 o Rough ER o Nucleolus o Nuclear Envelope o Nucleus For what reason are polyribosomes attached to the endoplasmic reticulum in RER? - Fig 2-15, 2-16, 2-21, 16-10 o Smooth ER o Rough ER List 3 functions associated with the smooth ER. - Fig 2-20, 2-21, 2-22 o Golgi Apparatus o Rough ER o Nucleus o Mitochondrion o Secretory granule What do the terms cis and trans Golgi mean? - Fig 2-23 o Golgi apparatus o Secretory Granules o Rough ER What is the difference between a secretory vesicle and a secretory granule? - Fig 2-24, 2-25 o Primary Lysosome o Secondary Lysosome o Golgi apparatus The enzymes in lysosomes are only active in a microenvironment with a pH of about 5. Why? - Fig 2-35 o Cellular Pigments § Lipofuscin § Melanin § Lipid droplets § Glycogen granules Why is lipofuscin sometimes called an age pigment? - Fig 2-27 o Peroxisomes Why are peroxisomes particularly abundant in neutrophils? - Fig 2-11, 2-12, 2-13 o Mitochondria o Cristae o Matrix What can the number and location of mitochondria in a cell tell you about the cell’s function? Slides - Slide Pancrease Fuchsin https://vmicro.iusm.iu.edu/virtual_h/msci_62_5.html o o o o - Nucleus Nuclear Envelope Nucleolus Secretory Granules Slide: Pancrease https://vmicro.iusm.iu.edu/virtual_h/msci_15_5.html (Fig. 4-24) o Basophilic Rough Endoplasmic Reticulum o Secretory Granules o Nucleus o Golgi Apparatus (Golgi Ghost ) Why are acinar cells of the pancreas said to be polarized? - Slide: mamarygland https://vmicro.iusm.iu.edu/virtual_h/msci_108_5.html (Fig. 6-1) o Lipid (droplets) - Slide 95: eye https://vmicro.iusm.iu.edu/virtual_h/msci_120_5.html (Fig. 2-25c) o Melanin (Granules) Notes Cell Division and Cell Death Cells throughout the body obviously exhibit a great degree of variation, both in their morphology and function. As we have seen, however, many cellular structures are common to most cell types. Structures segregated into distinct cellular compartments by membranes include the nucleus and the various organelles in the cytoplasm outside the nucleus. Each of these cellular components has a specific function and one can thus obtain a good indication of a cell’s activity by examining the distribution and morphology of these components. This lab will concentrate on the appearance of the cell nucleus and its contents. How nuclear structures are subdivided during mitosis and how they change during apoptosis (programmed cell death) are also considered. Objectives v Learn the probable functional activity of a cell based on the appearance of the nucleus and cytoplasmic organelles that are visible v Understand the structure and LM cytological appearance of chromosomes, chromatin, during mitosis and in the inter-mitotic period v Understand movements of chromosomes during mitosis and recognize the stages of mitosis in sections of blastula and certain adult tissues v Recognize cells in mitosis from cells undergoing programmed cell death, apoptosis Terms Cell (neuron) Nucleus (of neurons) Nucleolus (of neurons) Chromatin [S21, 22] Cytoplasm Nuclear Envelope Slides Ø Spinal cord https://vmicro.iusm.iu.edu/virtual_h/msci_149_5.html Ø Spinal ganglia https://vmicro.iusm.iu.edu/virtual_h/msci_09_5.html Sympathetic ganglia https://vmicro.iusm.iu.edu/virtual_h/msci_135_5.html Micrographs and diagrams Ø Fig 3-3 What does the presence of nucleoli tell you about the function of the cells? Nucleus Chromatin Nuclear Envelope Slides Ø 56: Liver cells https://vmicro.iusm.iu.edu/virtual_h/msci_29_5.html Ø How does the nuclear envelop differ structurally from the cell membrane and how are they similar? Chromosomes Prophase Metaphase Anaphase Telophase Slide Onion root tip https://vmicro.iusm.iu.edu/virtual_h/93_bl_5.html Junqueira Ø Fig 3-14, 3-15, 3-16 How do the events of mitosis relate to the events of the cell cycle’s S phase? Apoptotic Cells https://vmicro.iusm.iu.edu/virtual_h/93_bl_5.html Ø Fig 3-22, 3-23 Mitotic Cells Mitotic epithelial stem cells are found in the crypts, while the apoptotic epithelial cells are located near the tips of the villi. Slides Ø Lymph nodes https://vmicro.iusm.iu.edu/virtual_h/msci_79_5.html Ø Ø : Duodenum https://vmicro.iusm.iu.edu/virtual_h/msci_37_5.html Ø Micrograph Ø Fig 3-17 What are some differences in the appearance of mitotic and apoptotic cells? Notes Intercellular Junctions and Types of Epithelia Epithelium, one of the four primary tissues of the body, is characterized by having its cells lined up and oriented with their apical ends or surfaces facing one compartment and their basal ends on a basal lamina which anchors the epithelium to the underlying connective tissue. Unlike some other tissue types, epithelia consist almost entirely of cells, with little intervening space between the adjacent cells. Various types of junctions join adjacent epithelial cells. The histological classification of an epithelial layer is based on the shape of cells that compose it, particularly the cells on its apical or exposed surface and the number of cellular layers. These structural features also reflect the principal activities of the epithelium. Objectives v Learn criteria for identifying the various types of simple and stratified epithelia in light microscopy (LM) preparations v Understand how epithelia are classified into simple, stratified and pseudostratified v Understand that epithelium forms barriers and compartments by covering and lining the body’s outer and inner surfaces v Comprehend the general structure, organization and functions, as well as the specializations within epithelial cells in both LM and EM preparations v Understand the relationship between structure and function by comparing epithelia in various organs Electron Micrographs - - Fig 4-5 o Intercellular Junctions § Tight Junction § Zonula Adherens § Desmosomes Fig 4-6 o Tight Junction Fig 4-2 o Hemidesmosome Fig 4-7 o Gap Junction Fig 4-10 o Cilia o Microvilli Fig 4-8 o Microvilli Terms Simple Squamous Epithelium Simple Cuboidal Epithelium Simple Columnar Epithelium Examine the blood vessels and Bowman’s capsule to find simple squamous epithelium. Examine the tubules in the renal cortex, or outer region, for simple cuboidal epithelium. To find simple columnar epithelium, examine the ducts in the renal medulla, or inner region. Slide Ø Kidney https://vmicro.iusm.iu.edu/virtual_h/msci_14_5.html Ø Junqueira Ø Figs. 4-11 through 4-13 In sections of the kidney you should be able to find simple squamous epithelium in three different structures. How many do you see? Simple Columnar Epithelium Striated (Brush) Border (microvilli) Study the lining of the gall bladder lumen for simple columnar epithelium and observe the striated, or brush, border of the microvilli. Study the intestinal lining for simple columnar epithelium and observe the striated border of the epithelium. Slide Ø Ø 58: Gall Bladder https://vmicro.iusm.iu.edu/virtual_h/msci_105_5.html 43: Duodenum https://vmicro.iusm.iu.edu/virtual_h/msci_04_5.html How does the simple columnar epithelium differ in the kidney ducts and in the intestinal lining? Pseudostratified Columnar Ciliated Epithelium (PCCE) Basement Membrane Cilia Examine the thick basement membrane of the epithelium. Notice that the nuclei are located at varying levels throughout the epithelium. Observe the cilia lining the epithelium. Slide Ø 60: Trachea https://vmicro.iusm.iu.edu/virtual_h/140_bl_5.html Junqueira Ø Fig. 4-10, 4-16 Indicate three ways PCEE cells differ from simple columnar cells. Stratified Squamous (Non-Keratinized) Epithelium On Slide 91, examine the various layers of cells and the superficial layers lining the uterine cervix. These are the cells that are sampled during “Pap tests” for cervical metaplasia. On Slide 95, observe the outer surface of the cornea to find stratified squamous (non-keratinized) epithelium. Slides Ø 2T and 40: Esophagus https://vmicro.iusm.iu.edu/virtual_h/msci_43_5.html Ø 91: Uterine Cervix https://vmicro.iusm.iu.edu/virtual_h/133_bl_5.html Ø 95: Anterior Half of Eye https://vmicro.iusm.iu.edu/virtual_h/msci_120_5.html Junqueira Ø Fig. 4-14 Stratified Squamous Keratinized Epithelium Slide Ø 84: Thin skin, general body surface https://vmicro.iusm.iu.edu/virtual_h/msci_36_5.html Junqueira Ø Fig. 18-3 What do the various “strata” in this type of epithelium represent? Transitional Epithelium (also called urinary epithelium or urothelium) In Slide 69, examine the cell shapes in the layers of cells and notice that the epithelial lining is disrupted in some places. In Slides 70 and 71, notice the differences in the thickness of the lining, in the size and shape of the cells or nuclei, and in the convulsions of the epithelium. Slides Ø Ø Ø Ø Ø Ø 69: Ureter https://vmicro.iusm.iu.edu/virtual_h/msci_48_5.html 70: Distended (Full) Urinary Bladder https://vmicro.iusm.iu.edu/virtual_h/464_70b.html 71: Not-Distended (Empty) Urinary Bladder https://vmicro.iusm.iu.edu/virtual_h/msci_118_5.html Junqueira Ø Fig. 4-15 In what sense is this type of epithelium transitional? Notes Secretory Epithelia and Glands Glands can be classified structurally based on both the duct and the secretory portions. Ducts are said to be compound when they are branched and are simple when they are not branched. The overall shapes of the secretory portions of glands can be tubular, acinar (rounded), or tubulo-acinar (rounded with tubular end). The secretory portion can be further described as branched tubular or coiled tubular (long and not branched). Study Figures 4-20 and 4-21 in Junqueira for diagrammatic depictions of each type of gland. Objectives v Recognize the major differences in the morphologically different types of glands v Understand the various types of secretion shown by secretory cells of glands v Recognize staining differences between serous and mucous secretory cells v Understand the exocrine glands can be classified according to four features: § the secretory portion’s shape: alveolar vs. tubular § the duct system: simple vs. compound § the nature of the secretion: mucous vs. serous § the mode of secretion: merocrine, apocrine, or holocrine Terms Unicellular Glands (Goblet Cells) Simple Tubular Glands (Crypts of Lieberkühn or intestinal glands) Simple Columnar Epithelium Slide Ø Ø 45: https://vmicro.iusm.iu.edu/virtual_h/msci_26_5.html https://vmicro.iusm.iu.edu/virtual_h/msci_27_5.html Junqueira Ø Fig. 4-17 Ø Fig. 4-19 Ø Fig. 4-20 Ø Fig. 4-21 Try to distinguish the two significant parts of a gland: the secretory unit (acinus or tubule) from the duct. Simple branched tubular (Mucous) glands Slide Ø Ø 42: Pyloric Region of Stomach https://vmicro.iusm.iu.edu/virtual_h/msci_101_5.html How do simple branched tubular (mucous) glands resemble a unicellular gland? Simple Coiled Tubular (Sweat) Glands Secretory Portion Duct Slide Ø Ø 83: Sweat Glands in Thin Skin https://vmicro.iusm.iu.edu/virtual_h/msci_36_5.html What type of epithelium do the ducts of these glands have? Simple Branched Acinar (Sebaceous) Gland Sebaceous glands undergo holocrine secretion. Slide Ø Ø 85: Sebaceous Glands in Scalp http://medsci.indiana.edu/a464/virtual/464_85.html How exactly does this type of secretion work? Compound Acinar Glands Ducts [S53 only] Slides Ø 1T: Pancreatic Acini and Ducts Ø 53: Pancreatic Acini and Ducts https://vmicro.iusm.iu.edu/virtual_h/msci_154_5.html Ø What mode of secretion do pancreatic acinar cells show? Compound tubuloacinar glands Serous Cells Mucous Cells Ducts Compound tubuloacinar glands are located in breast lobules and undergo apocrine secretion. Slide Ø 51: Submandibular Salivary Gland https://vmicro.iusm.iu.edu/virtual_h/msci_72_5.html Which types of secretory cells in salivary glands are most like pancreatic acinar cells? Compound Tubuloacinar Glands Lactiferous Duct Slide Ø 88: Mammary Gland https://vmicro.iusm.iu.edu/virtual_h/msci_108_5.html Ø What specific material undergoes apocrine secretion in the mammary glands? Notes Extracellular Matrix and Types of Connective Tissue Connective tissue supports other tissues and connects all of the body’s tissues and organs together. In contrast to epithelium which is composed mainly of cells, connective tissues (CT) consist of material between or outside of cells, largely fibers and a gel-like ground substance. Cells tend to be widely separated among the masses of fibers and ground substances. The fibers and the ground substance are collective termed the extracellular matrix (ECM). The fibers, composed primarily of collagen or elastin, are responsible for the tensile strength and elasticity of the tissue. The ground substance, substantially composed of hydrated proteoglycans, provides the medium through which dissolved substances pass from capillaries to cells and back. Objectives v Identify and recognize the LM and TEM characteristics of extracellular matrix components, including both ground substances and fibers, and understand their functional significance v Recognize the LM appearance and function of the major cell types normally found in the different types of connective tissue v Recognize the traditional types of connective/support tissue and their functional significance Connective Tissue Overview • Connective tissue is organized with cells and material outside of cells. Connec&ve Tissue CT Extracellular Matrix ECM Cells Fibroblasts, macrophages, etc. • Extracellular matrix, ECM, is composed of fibers of protein and ground substance. Extracellular Matrix ECM Fibers of Protein Collagen and Elas9c Fibers • Ground Substance Ground substance consists of glycosaminoglycans and glycoproteins. Ground Substance Glycosaminoglycans GAGs Hyaluronic acid, chondroitan sulfate Electron Micrographs - Fig 4-2 o Basement Membrane o Collagen Fig 5-8 o Collagen o Fibroblast Fig 5-16 o Elastin o Collagen Glycoproteins Fibronec9n, Laminin Terms Mesenchyme Mesenchymal Cell Ground Substance (Glycosaminoglycans or GAGs) Mesenchyme is the embryonic tissue from which all forms of connective tissue are derived. Slide Ø 40a: Fetal tissue, primitive mesenchyme https://vmicro.iusm.iu.edu/virtual_h/464_40ab.html Junqueira Ø Fig. 5-1 Collagen Fibroblasts Areolar (loose) connective tissue Notice how the collagen fibers are eosinophilic. The loose areolar connective tissue is located around small blood vessels. Slide Ø Ø 8: Mesentery https://vmicro.iusm.iu.edu/virtual_h/msci_116_5.html https://vmicro.iusm.iu.edu/virtual_h/msci_45_5.html Junqueira Ø Fig. 5-21 Fibroblasts Elastic Fibers Slide Ø 4a: Mesentery https://vmicro.iusm.iu.edu/virtual_h/464_4ab.html Junqueira Ø Fig. 5-13, 5-14 How does the appearance of loose connective tissue in a mesentery compare to that in sections? Fibroblasts Collagen Basement Membrane The fibroblasts and collagen bundles are located below the epithelium of the lumen. The thick basement membrane of the epithelium lines the lumen. Slide Ø Ø 60: Trachea https://vmicro.iusm.iu.edu/virtual_h/140_bl_5.html Dense Irregular Connective Tissue § Fibroblast § Collagen Adipocytes (Fat Cells) Slide Ø 83: Skin, dermis https://vmicro.iusm.iu.edu/virtual_h/msci_157_5.html Junqueira Ø Fig. 5-21 Ø Fig. 6-1 What are some differences and similarities between dense irregular and loose connective tissue? Dense Regular Connective Tissue § Collagen § Fibroblasts Examine the appearance of tendon. Note the regular parallel arrangement of the collagen fibers and the relative absence of cells other than fibroblasts. Slide Ø 23a: Tendon https://vmicro.iusm.iu.edu/virtual_h_nw/nw_hist_1_16.html Ø testes capsule https://vmicro.iusm.iu.edu/virtual_h/119_bl_5.html Ø Junqueira Ø Fig. 5-22 What is the major difference between dense regular and dense irregular connective tissue? Reticulin Fibers This was stained specifically to highlight the black reticulin fibers. Slide Ø 5: Lymphoid tissue https://vmicro.iusm.iu.edu/virtual_h/99_bl_5.html Junqueira Ø Fig. 5-23 Speculate as to the general function of reticulin fibers in this special type of connective tissue. Notes Muscle Movement of body parts depends primarily on muscular tissue, the third fundamental tissue type. The importance of this tissue is emphasized by the fact that almost half the body’s mass consists of muscle. There are three types of muscle, namely 1) skeletal muscle primarily involved in voluntary movement of bones 2) cardiac muscle which enables the heart to beat so blood can be circulated involuntarily and 3) visceral or smooth muscle which provides tone and involuntary movement of hollow tubes and organs such as the blood vessels, intestine and uterus. Objectives v Understand the formation of skeletal muscle v Understand the arrangement and relationship between muscle fibers and connective tissue in skeletal muscle v Identify the different unique structural features of skeletal, visceral and cardiac muscle at the LM and EM levels and be able to distinguish these three muscle types v Recognize the arrangement of myofilaments in skeletal muscle and the functional significance of this arrangement for contraction Electron Micrographs - - - Fig. 10-7 o Skeletal Muscle § Cross Striations § I Band § A Band § Z Band (Z line) § Sarcomere Fig. 10-10 o Skeletal Muscle § T-tubules § Sarcoplasmic Reticulum Fig. 10-20 o Smooth Muscle Fig. 10-17, 10-18 o Cardiac Muscle § Intercalated Disk Terms Developing Skeletal Muscle Myoblasts Myotubes Myoblasts illustrate the embryological development of muscle from mesenchymal cells. Later in development myoblasts fuse to form multinucleated myotubes. Slides Ø 13, 40a: Fetal tongue https://vmicro.iusm.iu.edu/virtual_h/464_40ab.html Ø Junqueira Ø Fig. 10-2 Make a sketch here showing how skeletal muscle forms. (Mature) Skeletal Muscle (a.k.a. Striated Muscle) Muscle Cells (Fibers) Cross Striations A Band [not in S17a, 35] I Band [not in S17a, 35] Perimysium Endomysium [not in S17] Epimysium [not in S17] Fascicle The most characteristic features of skeletal muscle are large, multinucleate fibers with crossstriations. Remember that in muscle, fibers are actually multinucleated cells. On the slides of both tongue and lip, notice that the perimysium is the loose connective tissue between the fascicles. Also on those slides, if epimysium is present, observe its dense irregular connective tissue. Slides Ø 3T, 17: Skeletal muscle, longitudinal section https://vmicro.iusm.iu.edu/virtual_h/464_17_5.html Ø 17a: tongue https://vmicro.iusm.iu.edu/virtual_h/msci_70_5.html Ø 35: lip https://vmicro.iusm.iu.edu/virtual_h/msci_67_5.html Ø Junqueira Ø Fig. 10-3, 10-4 What are the functions of the endomysium and perimysium? Most skeletal muscle associated with the GI tract is smooth, not skeletal. Why are lingual muscles not composed of smooth muscle? Smooth Muscle Muscle Cells (Fibers) Smooth muscle has non striated fibers of smaller diameter than skeletal muscle fibers, with one nucleus/fiber. Notice how the muscle fibers have been cut in various planes. Compare the features of smooth muscle with those you studied in skeletal muscle. Slides Ø 40: esophagus https://vmicro.iusm.iu.edu/virtual_h/66_bl_5.html Ø 46: ileum https://vmicro.iusm.iu.edu/virtual_h/msci_37_5.html Junqueira Ø Fig. 10-19, 10-21 Are fiber diameters larger in skeletal or smooth muscle? How about fiber length? Cardiac Muscle Muscle Cells (Fibers) Intercalated Disks Cross Striations Fibers of cardiac muscle have features somewhat intermediate between those of skeletal and visceral muscle. The intercalated discs are key features of cardiac muscle. Slides Ø 5T, 18, 18a: Heart ventricle https://vmicro.iusm.iu.edu/virtual_h/msci_139_5.html Ø Junqueira Ø Fig. 10-16 Can you give a functional explanation as to why cardiac muscle has many histological features that are intermediate between skeletal and smooth muscle? Notes Blood Cells and Hemopoiesis Blood can be considered a special form of connective tissue in which highly specialized cells are suspended in a fluid matrix called plasma. Blood flow serves to transport many diverse substances, from gases, nutrients, and wastes to “information-bearing” molecules such as hormones and antibodies. In stained blood smears, one can quickly distinguish between the oxygen-carrying erythrocytes which lack nuclei and the basophilic, nucleated leukocytes which perform many diverse roles in bodily defense. Objectives v Learn and identify all types of mature blood cells and platelets by their morphological characteristics v Recognize precursors of various blood cells v Understand the process of blood cell formation, hemopoiesis, in bone marrow v Recognize the structural features and significance of bone marrow Electron Micrographs - Fig. 12-4 o Erythrocytes Fig. 12-8 o Neutrophil Fig. 12-9 o Eosinophil Fig 12-10 o Basophil Fig. 12-11 o Lymphocyte Fig. 12-12 o Monocyte Fig. 12-13 o Platelets Terms Erythrocytes Lymphocytes Neutrophils Eosinophils Basophils Monocytes Platelets Erythrocytes are red blood cells and are recognized by their anuclear, biconcave shape. Since erythrocytes are the most abundant cells in blood, they will predominant in your field of view. The various kinds of leukocytes are all much less numerous. Lymphocytes have spherical nuclei with relatively little cytoplasm. Neutrophils are polymorphic and have highly lobulated nuclei. Eosinophils may be the rarest of the blood cells. They have a bilobed nucleus and contain eosinophilic granules, as their name indicates. Basophils, rare as well, also have a bilobed nucleus and contain basophilic granules. Monocytes are the largest of the blood cells which accounts for their large U-shaped nucleus. Platelets are small cell fragments of the blood derived from megakaryocytes in bone marrow. Platelets and all blood cells are sometimes referred to as the “formed elements” of blood. Slide Ø 23: Blood Smear https://vmicro.iusm.iu.edu/virtual_h/10_2_bl_5.html Ø Junqueira Ø Figs. 12-6 through 12-13 In the space provided below, sketch an example of a lymphocyte, a neutrophil, a monocyte and some platelets in a scale relative to one another. Give at least one major function for each of the types of the seven formed elements just studied. Blood Cell Precursors Megakaryocytes Adipocytes Since bone marrow is the site of hemopoiesis, take note of the precursors which would eventually develop into blood cells. Note the large, multiple, and polyploid nuclei of the megakaryocyte. Slides Ø 77: Bone Marrow https://vmicro.iusm.iu.edu/virtual_h/127_bl_5.html Ø 22a: Needle biopsy https://vmicro.iusm.iu.edu/virtual_h/msci_153_5.html Junqueira Ø Fig, 13-2 How do megakaryocytes form platelets? Bone Marrow Cavity Stroma Blood Cell Precursors Megakaryocytes Examine the bony projections that line the marrow cavity. These are covered by a CT layer called endosteum which may be difficult to see. The stroma, or loose connective tissue, is filled with blood cell precursors which are organized in cords or clusters. Blood vessels with dilations called vascular sinuses are also present in marrow. Slides Ø 13a: Developing Bone https://vmicro.iusm.iu.edu/virtual_h/34_bl_5.html Ø What is the cellular difference between red and yellow bone marrow? How do newly formed blood cells move from the stroma into the bloodstream? Notes The Circulatory System The circulatory system is responsible for the movement of blood throughout the body, with the purpose of delivering oxygen and nutrients to tissues and disposing of waste products from the tissues. The system consists of a pump, the heart, and an extensive network of channels, the arteries, veins and capillaries. The arteries carry blood away from the heart. Because their walls are very thin, the capillaries allow for exchange of material between the blood and the tissues. The veins return the blood to the heart. In addition to blood vessels, a second network of channels, the lymphatic vessels, will also be studied in this exercise. Recall that these vessels carry lymph, intercellular fluid, which is filtered through lymph nodes and eventually returned back to the blood. Objectives v to understand the overall organization and histological features of the heart and major blood vessels v to recognize the histological features that distinguish arteries from veins v to recognize arterioles, capillaries and venules in LM preparations and understand how their structures relate to their functions v to be able to recognize lymphatic vessels Terms Heart Epicardium Myocardium Cardiac Muscle Purkinje Fibers Endocardium Endothelium Identity the three lays of the heart wall. Note that the myocardium is the thickest layer due to the presence of cardiac muscle, Purkinje fibers and small blood vessels. The epicardium is a relatively thick layer of fatty connective tissue and contains small nerves and large coronary vessels. Slide Ø 18: Heart https://vmicro.iusm.iu.edu/virtual_h/msci_139_5.html Junqueira Ø Figs. 11-3 through 11-6 Compare and contrast at least 3 histological features of the endocardium and the epicardium. Artery (Elastic or muscular) Tunica Intima Endothelium Tunica Media Tunica Adventitia Vasa Vasorum Elastic arteries, for example, the aorta, receive blood directly from the heart and are hence, the largest of the arteries. Slide Ø 25: Elastic Artery (Aorta) https://vmicro.iusm.iu.edu/virtual_h/msci_115_5.html Ø Van Gieson stain Aorta https://vmicro.iusm.iu.edu/virtual_h/msci_100_5.html Ø Junqueira Ø Figs. 11-7 through 11-11 Which is thicker in the media: one of the layers of smooth muscle or a layer of elastic material? Vein (Vena Cava) Tunica Intima Tunica Media Tunica Adventitia Vasa Vasorum Veins conduct blood away from body tissues. Veins generally have a larger diameter than arteries, though the width of their walls are thinner than arteries. Like arteries, veins also have three distinct layers: the tunica intima, the tunica media and the tunica adventitia. The vasa vasorum supply both elastic and muscular arteries. Slides Ø 26: Vena Cava: https://vmicro.iusm.iu.edu/virtual_h/464_26b.html Junqueira Ø Fig. 11-21, 11-22 What are 2 major histological differences between veins and arteries? Vein Tunica Intima Tunica Media Tunica Adventitia Vasa Vasorum Muscular arteries send blood to various organs. Slides Ø 24: vein https://vmicro.iusm.iu.edu/virtual_h/msci_49_5.html Ø 15: https://vmicro.iusm.iu.edu/virtual_h/464_15bb.html Ø Compare and contrast the muscular artery and the elastic artery. What is major difference between these arteries and an elastic artery, besides their size? How does the muscle in the large vessels differ from that in the heart? Arterioles Tunica Intima Tunica Media Tunica Adventitia Meta-Arterioles Capillaries Post-Capillary Venules Venules Tunica Intima Tunica Media Tunica Adventitia Vein Tunica Intima Tunica Media Tunica Adventitia Lymphatic Vessel (only on 8) Neurovascular Bundle (only on 8) Arteries have three distinct layers: the tunica intima, the tunica media and the tunica adventitia. The smallest branches of arteries are the arterioles, a term Junqueira defines as a vessel in which the tunica media has six or fewer layers of smooth muscle. Lymphatic vessels drain interstitial fluid, lymph, from lymphatic spaces and eventually join the thoracic duct and the right lymphatic duct. From there, the lymph drains into the venous system. Lymph travels through the vessels primarily by the movement of surrounding organs and tissue. Slide Ø 8: Mesentery https://vmicro.iusm.iu.edu/virtual_h/mesent_464_8.html Ø 18: Heart https://vmicro.iusm.iu.edu/virtual_h/65_bl_5.html Ø Junqueira Ø Figs. 11-13 through 11-20 What is the most important part of the microvasculature? State some of its functions. What are the 3 general kinds of capillaries and how do their functions differ? What is the best method to tell a lymphatic vessel from a small vein? Notes The Immune (Lymphoid) System Lymphoid tissues and organs, along with the lymphatic vessels constitute a very widespread and extremely important filtering system between the body tissues (where foreign substances and organisms can enter) and the blood stream. Today’s lab will focus on distinct lymphoid organs, like the lymph nodes, the thymus and the spleen as well as more diffuse collections of lymphocytes, which are primarily located along the mucosa of the digestive and respiratory tracts. Objectives v Recognize lymphocytes in the various immune organs v Distinguish the different lymphatic organs in LM preparations v Recognize the different regions of lymph nodes, spleen and thymus v Know the major functional significance of the lymph nodes, spleen and thymus v Understand the filtration mechanism for lymph in the lymph nodes and for blood in the spleen Electron Micrographs - Fig. 12-11 o Lymphocytes Terms Thymus Capsule Septa Cortex Epithelial Reticular Cell (or Cortical Thymic Epithelial Cell) Medulla Hassall’s Corpuscle Epithelial Reticular Cell (or Medullary Thymic Epithelial Cell) First note the capsule and septa. Next notice the organization of lobes into a basophilic cortex and eosinophilic medulla. A key feature of the medulla is the presence of Hassal’s corpuscles, which are masses of degenerated epithelial cells. The epithelial reticular cells make up the framework of the thymus. Slide Ø 29: Adult Thymus https://vmicro.iusm.iu.edu/virtual_h/464_29b.html Ø 27a: Child Thymus https://vmicro.iusm.iu.edu/virtual_h/msci_126_5.html Junqueira Ø Figs. 14-10 through 14-13 What is the function of the individual epithelial reticular cells? How do the lymphocytes seen here differ from those in the blood smears studied earlier? Lymph Node Capsule Subcapsular Space Trabeculae Reticulin Fibers (only S5) Cortex Lymphoid Follicle Paracortex Medulla Medullary Cord Plasma Cell (not on S5) Efferent Lymphatic (only S28a) Slide Ø 28: Lymph Node (Giemsa stain) https://vmicro.iusm.iu.edu/virtual_h/464_28b.html Ø 28a: Lymph Node https://vmicro.iusm.iu.edu/virtual_h/msci_42_5.html Ø 5: Lymph Node (Silver Impregnation) https://vmicro.iusm.iu.edu/virtual_h/99_bl_5.html Junqueira Ø Fig. 14-17 through 14-22 How does the stroma of a lymph node differ from that of the thymus? How is lymph filtered as it moves through the nodes? Mucosa-Associated Lymphoid Tissue (MALT) Ileum Lymphoid Follicle Lymphocyte Peyer’s Patches Tonsil Lymphoid Follicle Lymphocyte Appendix Lymphoid Follicle Lymphocyte Slides Ø 45: Ileum https://vmicro.iusm.iu.edu/virtual_h/msci_37_5.html Ø 27: Tonsil https://vmicro.iusm.iu.edu/virtual_h/msci_136_5.html Ø 47: Appendix https://vmicro.iusm.iu.edu/virtual_h/msci_41_5.html Junqueira Ø Figs. 14-14 through 14-16 Ø Fig. 15-32 Ø Fig. 15-39 In what sense is the MALT system the first line of the body’s defense? Does it resemble more closely a lymph node or the thymus? Spleen Capsule Trabeculae Red Pulp Pulp Cord Vascular Sinusoids Stave Cells White Pulp Lymphocyte Central Arteriole Slide Ø 30: Spleen https://vmicro.iusm.iu.edu/virtual_h/msci_68_5.html Ø 30a: Spleen https://vmicro.iusm.iu.edu/virtual_h/msci_18_5.html Junqueira Ø Figs. 14-24 through 14-29 What is one unique aspect of the spleen compared to other immune organs? In what sense is blood filtered as it moves through the spleen? Notes Central Nervous System Nervous tissue is the fourth and last fundamental tissue type to be considered and is actually a complex organization of several cell types. In addition to various kinds of neurons, it contains glial cells of several different varieties and blood vessels with connective tissue coverings. The neurons are specialized to conduct impulses. The glial cells are involved in the nutrition and the formation of sheaths around the neurons and play an important role in inflammatory reactions. Objectives v Understand the major histological differences between central nervous tissues and other tissues v Recognize the major components of the spinal cord in transverse section v Recognize certain regions and specific neuronal types in the brain v Identify and learn the specific roles of the major types of glial cells in the CNS Terms Spinal Cord White Matter Neuropil Gray Matter Neuron Cell Bodies Nissl Substance (Rough ER) Glial cell nuclei Dorsal Horns Ventral Horns Central Canal Ependymal Cell Slide Ø 6T: Spinal Cord https://vmicro.iusm.iu.edu/virtual_h/msci_149_5.html Ø 19a: Spinal Cord (Myelin Stain) https://vmicro.iusm.iu.edu/virtual_h/464_19ab.html Junqueira Ø Figs. 9-3, 9-14, 9-17, 9-18 What are the major types of glial cells in the spinal cord and where are they located? How are the appearances of white and gray matter different in the myelin-stained and the H&E stained slides? Indicate three functions of the cells present in the ependyma. Cerebrum Meninges Pia Arachnoid White Matter Gray Matter Pyramidal Cell Neuroglial Cell Astrocyte Oligodendrocyte Slide Ø 94: Cerebrum https://vmicro.iusm.iu.edu/virtual_h/msci_125_5.html Junqueira Ø Figs. 9-15 and 9-19 Is dura mater present on your slide? If not, can you guess why? List several functions of astrocytes. Cerebellum White Matter Myelinated Axon Gray Matter Molecular Layer Purkinje Cell Granular Layer Slide Ø 96: Cerebellum https://vmicro.iusm.iu.edu/virtual_h/msci_148_5.html Ø Nissl stain https://vmicro.iusm.iu.edu/virtual_h/71_bl_a.html Junqueira Ø Fig. 9-16 List names of neurons found in the cerebellum and give their most important cytological features. What features do Purkinje cells show especially well? Notes Peripheral Nervous System The peripheral nervous system is an extension of the central nervous system. The reception of information is the function of the sensory component of the peripheral nervous system, or PNS. The transmission of the response to the effector organ is relegated to the motor component of the PNS. Peripheral nerves are composed of bundles of axons and dendrites. Each nerve is enclosed by an epineurium. Bundles, or fascicles of axons are surrounded by several layers of flattened fibroblastic cells, the perineurium. Each axon and dendrite is invested by a Schwann cell which is surrounded by basal lamina. The Schwann cells are also surrounded by another thin layer of CT, the endoneurium. Objectives v Recognize the microscopic features of peripheral nerves and ganglia in light microscopy v Recognize the structural and ultrastructural features of the myelin sheath v Understand the role of Schwann cells in myelinated and unmyelinated nerves v Identify the ultrastructural features of synapses Electron Micrographs Study the EMs and diagrams on Junqueira pages 160 through 163 and identify the following components of the peripheral nervous system. Schmidt-Lantermann clefts Myelin Axons Terminal Bouton Synaptic vesicles Postsynaptic cleft Mitochondria Terms Nerve (Fibers) Schwann Cell Myelin Sheath Node of Ranvier Axon Examine Slide Ø 44: Isolated Nerve Fibers https://vmicro.iusm.iu.edu/virtual_h/msci_151_5.html Ø Junqueira Ø Figs. 9-23 and 9-26 What exactly is a node of Ranvier? Nerve Epineurium Perineurium Fascicles Endoneurium (only on 19) Myelin Sheath Axons (only on 19) Slide Ø 19: Peripheral Nerve https://vmicro.iusm.iu.edu/virtual_h/464_19b.html Ø 20: Peripheral Nerve (Osmium Treatment) https://vmicro.iusm.iu.edu/virtual_h/150_bl.html Junqueira Ø Figs. 9-26, 9-27 What are the major histological and functional differences between the myelin sheath and the endoneurium? Small nerves and Neurovascular Bundle Nerve (Fibers) Schwann Cell As is demonstrated by the neurovascular bundle, arteries and veins are associated with nerves. Slide Ø 8: Mesentery https://vmicro.iusm.iu.edu/virtual_h/mesent_464_8.html Ø Junqueira Ø Fig. 9-28 Does the outer layer of connective tissue in the small nerves resemble a perineurium or an epineurium? Spinal and sympathetic Ganglia Capsule Satellite Cell Nerve (fibers, myelinated) Neuron Cell Body Schwann Cell Slide Ø Ø Ø Ø 21: Spinal Ganglion https://vmicro.iusm.iu.edu/virtual_h/msci_137_5.html 22a: Spinal Ganglion (Osmium Treatment) 6T: Spinal Cord https://vmicro.iusm.iu.edu/virtual_h/msci_09_5.html 22: Sympathetic Ganglion https://vmicro.iusm.iu.edu/virtual_h/msci_135_5.html Junqueira Ø Fig. 9-29 What is the significance of Nissl substance? What is the function of the satellite cells? Notes Sensory Receptors There is quite a variety of structures throughout the body whose function is to detect stimuli of different types and have that stimulus initiate a nerve impulse for transmission back to the CNS. Many such sensory receptors are little more than bare, unmyelinated axon endings and are usually not visible histologically. Others are more complex and are associated with CT or cellular structures. Some of these more complex sensory strictures will be studied here. Physiologically these receptors can be considered as chemoreceptors or mechanoreceptors. Objectives v Recognize taste buds on lingual papillae and understand how their structure facilitates taste perception v Recognize Meissner’s and Pacinian corpuscles in the skin v Identify olfactory epithelium and understand its function v Learn the general structure of the organ of Corti in the inner ear and the roles of its structural components in hearing Terms Tongue Circumvallate Papilla Taste Buds Gustatory Cells Taste Pores Von Ebner’s Glands Slide Ø 36a: Tongue https://vmicro.iusm.iu.edu/virtual_h/msci_70_5.html Ø https://vmicro.iusm.iu.edu/virtual_h/8_bl_5.html https://vmicro.iusm.iu.edu/virtual_h/77_bl_5.html Junqueira Ø Fig. 15-4, 15-5, 15-6 What is the difference between gustatory and sustentacular cells? Is Von Ebner’s gland serous or mucous and how does its function relate to sensation? Skin Epidermis Dermis Dermal Papillae Meissner’s (Tactile) Corpuscle Hypodermis Pacinian (Lamellated) Corpuscle Slide Ø 7T: Skin https://vmicro.iusm.iu.edu/virtual_h/msci_36_5.html Ø https://vmicro.iusm.iu.edu/virtual_h/msci_05_5.html Ø 87: Fingertip https://vmicro.iusm.iu.edu/virtual_h/464_87b.html Junqueira Ø Fig. 18-10 Ø Fig. 18-11 What physiological “type” of receptor would Meissner’s and Pacinian corpuscles both represent? Olfactory Epithelium Respiratory Epithelium Slide Ø 8a: Nasal cavity (dog) https://vmicro.iusm.iu.edu/virtual_h/464_8b.html Ø 12a: Fetal Pig Head https://vmicro.iusm.iu.edu/virtual_h/464_12ab.html Junqueira Ø Fig. 17-2 and 17-3 Compare and contrast olfactory and respiratory epithelia. What is the physical basis of olfaction? Cochlea Scala Vestibuli Scala Tympani Scala Media (Cochlear Duct) Vestibular Membrane Basilar Membrane Tectorial Membrane Organ of Corti Spiral Ganglion Slides Ø 92: Cochlea (Guinea Pig) https://vmicro.iusm.iu.edu/virtual_h/121_bl_5.html Junqueira Ø Fig. 23-29, 23-30 What is the function of the stria vascularis? How exactly does movement of the oval and round windows produce auditory sensations via the organ of Corti? Notes The Eye Each eye is derived as an outgrowth of the brain in the early embryo and the unique and highly complex structure of the eye reflect its origin. In studying a histological section of the eye, one must keep in mind the fact that it is composed basically of three layers and that, in the living state, the anterior portion of the eye is filled with fluid which is being continually produced and absorbed. The posterior region behind the lens is filled with an almost fluid form of CT called vitreous humor. The lens itself always hardens very severely during fixation and is difficult to section. Objectives v to understand the general organization of the eye and recognize the major tissues of the eye and their basic functions v to be able to recognize the various major layers of the eye (corneosclera, uvea, and retina) Slides Ø 93: Eye https://vmicro.iusm.iu.edu/virtual_h/msci_78_5.html Ø 95: Eye (Anterior) https://vmicro.iusm.iu.edu/virtual_h/msci_120_5.html Ø Junqueira Ø Fig. 23-1 through 23-17 Terms Eye Anterior Chamber Anterior Cavity Posterior Cavity Posterior Chamber Sclera (Fibrous Tunic) Cornea Corneal Epithelium Bowman’s (external) Membrane Stroma Descemet’s (internal) Membrane Corneal Endothelium How does the cornea differ histologically and functionally from the sclera? Compare and contrast Bowman’s and Descemet’s membranes. Canal of Schlemm What is one important function of this canal? Uvea (Uveal Layer, Vascular Tunic) Choroid Ciliary Body Ciliary Muscle Ciliary Processes Supsensory Ligaments (or Zonule) Iris What is the functional significance of the ciliary processes? Indicate some unusual histological features of the iris. Lens Capsule Fibers What is a “cataract” of the eye and why would they form in lens tissue but not in other tissue? The structures below are only found on slide 93 Sensory Tunic Retina Pigmented Layer Processes of Rods and Cones Nuclei of Rods and Cones Inner Nuclear Layer Ganglion Layer What must light pass through before it hits rods and cones? What exactly are the “photoreceptors” in the rods and cones? What is the significance of the neuronal cell bodies in the retina? Indicate three functions of the pigmented layer of the retina. Notes Integument (Skin) The skin constitutes an organ system with a variety of important functions. Consisting of dermal and epidermal layers, the skin protects the body from various kinds of mechanical injury and constitutes a major defense against invasion of foreign organisms. Having various “epidermal appendages” (hair, nails, sweat glands and sebaceous glands), skin is also critical for maintaining the body’s temperature and preventing desiccation. The skin contains many sensory receptors for various kinds of stimuli and represents the site of interaction between the body and the environment. In addition, skin has various metabolic functions such as synthesis of vitamin D by cells of the epidermis. The protective, sensory and thermoregulatory functions of the integument are reflected in its complex histology. Objectives v Understand the major layers and tissue components of skin and their functional significance v Recognize the different histological layers within the epidermis and how these relate to the process of keratinization and epidermal function v Understand the formation and function of various epidermal appendages such as hair and nails Terms Epidermis Stratum Corneum Stratum Granulosum Stratum Spinosum Stratum Lucidum (slide 33a only) Stratum Basale Melanocytes Keratinocytes Dermis Papillary Layer Dermal Papillae Reticular Layer Hypodermis (Subcutis) Thick skin is found on fingertips, palms and soles of feet. It is specialized for protection during friction and contains sensory receptors responsive to pressure, the Pacinian corpuscles. Thin skin covers most of the body and is similar in many respects to thick skin. For example, thin skin contains hair follicles but does not have Pacinian corpuscles to respond to pressure and friction. Slide Ø 83: Thick Skin https://vmicro.iusm.iu.edu/virtual_h/msci_05_5.html Ø 33a: Thick Skin https://vmicro.iusm.iu.edu/virtual_h/89_bl_5.html Ø 84: Thin Skin https://vmicro.iusm.iu.edu/virtual_h/msci_36_5.html Ø Junqueira Ø Figs. 18-2 through 18-9 What do the small “spines” on keratinocytes of the spinous layer represent? What is contained in the granules of the keratinocytes of the granular layer? Since the cells there are dead, why is the cornified layer so critically important? How does melanin get from the melanocytes into the keratinocytes? List several functions of the dermis and hypodermis. Eccrine and apocrine Sweat Glands Secretory Portion Duct Slide Ø 44a: Skin of Axilla https://vmicro.iusm.iu.edu/virtual_h/464_44b.html Junqueira Ø Figs. 18-16, 18-17 What is the functional significance of having apocrine sweat glands in skin of only certain body areas? Hair Follicles Internal Root Sheath External Root Sheath Hair Bulb Dermal Papillae (of hair) Arrector Pili Muscle Sebaceous Gland Slides Ø 85: Skin of Scalp (Vertical Section) https://vmicro.iusm.iu.edu/virtual_h/464_85b.html Ø 86: Skin of Scalp (Oblique Section) https://vmicro.iusm.iu.edu/virtual_h/464_86b.html Junqueira Ø Figs. 18-12, 18-13, and 18-15 What is the function of the “pilosebaceous unit” in the skin? Nail Plate Nail Bed Nail Root Nail Fold Eponychium Hyponychium Slide Ø 42a: Fingertip Junqueira Ø Fig. 18-14 How exactly does cell proliferation and keratinization produce a nail? Notes Cartilage and Bone Cartilage is a form of CT that forms the supportive framework of certain organs, the articulating surface of bones and the greater part of the fetal skeleton. The cartilage of the fetal skeleton is eventually replaced by bone. Three types of cartilage will be studied in today’s lab: hyaline cartilage, elastic cartilage and fibrocartilage. Cartilage is a nonvascular and pliable, yet strong, material composed of proteoglycan matrix. Embedded in this matrix are the fibrous and cellular components of cartilage. Objectives v Recognize the microscopic features of both the matrix and the cells in cartilage and bone v Understand the structural and functional differences among types of cartilage v Understand the microscopic structure of bone and the functional significance of osteons Electron Micrographs - Fig 7-7 o Chondrocytes Terms Hyaline Cartilage Perichondrium Chondroblasts Lacunae Chondrocytes Slide Ø 60: Trachea https://vmicro.iusm.iu.edu/virtual_h/140_bl_5.html Ø 13: Fetal Foot https://vmicro.iusm.iu.edu/virtual_h/464_13b.html Junqueira Ø Fig. 7-1, 7-2 What is a major physiological property of hyaline cartilage? Elastic Cartilage Perichondrium Chondroblasts Lacunae Chondrocytes Elastic Fibers Slide Ø 9: Ear https://vmicro.iusm.iu.edu/virtual_h/056_bl_5.html Ø Junqueira Ø Figs. 7-1, 7-4 What is the function of perichondrium? Fibrocartilage Lacunae Chondrocytes Collagen Bundles Note the absence of the perichondrium. Slides Ø 14a: Fibrocartilage https://vmicro.iusm.iu.edu/virtual_h/131_bl_5.html Junqueira Ø Fig. 7-5 How does the location of fibrocartilage help explain why it must be different from hyaline and elastic cartilage? Bone (Ground) Osteon (Haversian System) (not on longitudinal sections) Lamellae Lacunae Canaliculi Haversian Canal (aka Central Canal) Interstitial Lamellae (not on longitudinal sections) Volkmann’s Canal (longitudinal section on Slide 11 only) Slide Ø 11: Ground Bone (Cross section and Longitudinal) https://vmicro.iusm.iu.edu/virtual_h/32_bl_5.html Junqueira Ø Figs. 8-1, 8-9, 8-10 What is the function of canaliculi and how do they form? What other structure in bone do Volkmann’s canals resemble functionally? Bone (Decalcified) Periosteum Osteoblasts Osteon Central Canal Lacunae Osteocytes Endosteum Marrow Notice that the periosteum consists of both a fibrous layer and an osteogenic layer with osteoblasts. Slide Ø 12: Decalcified Bone http://medsci.indiana.edu/a464/virtual/464_12.html Junqueira Ø Figs. 8-2, 8-5, 8-6, 8-8 Compare and contrast the structures of periosteum and endosteum. Notes Bone Formation Bone is the other specialized connective tissue in which extracellular specializations for support are maximal within the limits required for development and remodeling. There are two types of bone development: intramembranous and endochondral ossification or osteogenesis. Intramembranous ossification gives rise to “membrane bones,” these being the flat bones of the skull and parts of the mandible. This process involves the deposition of bone matrix, osteoid, directly in regions, or membranes, of embryonic mesenchyme. Bones of the extremities, pelvis and vertebral column, cartilage bones, are formed by endochondral ossification. This process involves the initial formation of a hyaline cartilage model followed by its replacement with bone. Regardless of the ossification process, the histological structure of the bone is the same. Objectives v Understand the two mechanisms of bone formation, their differences and similarities v Recognize the appearances and significance of the various zones present in a bone v Recognize and know the functional significance of the parts comprising a synovial joint Terms Intramembranous Bone Formation Mesenchyme Periosteum Trabeculae Osteoblasts Osteoid (Demo) Lacunae Osteocytes Bone (Calcified) Note that the mesenchyme is embryonic loose connective tissue. Slide Ø 12a: Fetal Guinea Pig Head https://vmicro.iusm.iu.edu/virtual_h/msci_130_5.html Junqueira Ø Figs. 8-12, 8-13 Where would you expect mesenchyme to persist the longest during formation of the skull? What is happening chemically in osteoid that converts it to bone? Endochondral Bone Formation Epiphysis Hyaline Cartilage Diaphysis Primary Ossification Center Secondary Ossification Center Periosteum Bone Lacunae Osteocytes Epiphyseal Growth Plate Zone of Proliferation Zone of Maturation and Hypertrophy Zone of Degeneration and Osteogenesis Slide Ø 15a: Fetal Joint https://vmicro.iusm.iu.edu/virtual_h/464_15b.html Ø https://vmicro.iusm.iu.edu/virtual_h/34_bl_5.html Junqueira Ø Figs. 8-14 through 8-17 Why are periosteal cells and osteoprogenitor cells not necessarily the same thing? List exactly what is happening at the cellular level as you move from the epiphyseal cartilage to the diaphyseal bone marrow. Joint Cavity Joint Capsule Ligaments Slides Ø 15a: Fetal Joint https://vmicro.iusm.iu.edu/virtual_h/464_15b.html Junqueira Ø Figs. 8-19, 8-20, 8-21 What type of tissue is the synovium and what is its function? What feature(s) of a synovial joint often decrease with age, requiring the joint to be replaced with a artificial joint? Fibrocartilage / Intervertebral disk Slide 14a: Intervertebral disk https://vmicro.iusm.iu.edu/virtual_h_nw/nw_hist_1_23.html Junqueira Fig. 8-22 Notes Teeth and Tooth Formation Like bone, teeth include very hard calcified components, but unlike bone this tissue does not turnover or get repaired in the course of a person’s lifetime. Teeth are usually considered in the context of the digestive system or oral cavity, as in Junqueira, but will be covered here in the context of calcified tissue. As you study tooth biology here, note the similarities and differences between the formation and maintenance of this tissue with bone. Objectives v Recognize the major components of teeth in the LM v Understand the process of tooth formation and recognize the basic embryonic structures involved in tooth development Terms Tooth (Ground) Pulp Cavity Dentine Enamel Cementum Slide Ø 38: Ground Tooth https://vmicro.iusm.iu.edu/virtual_h/129_bl_5.html Junqueira Ø Figs. 15-7 through 15-9 Which hard component of the tooth most resembles bone histologically? What do the parallel line (rods or prisms) in enamel represent? Tooth (Developing) Enamel Organ Ameloblasts Enamel Dentine Predentine Odontoblasts Slide Ø 38a: Developing Tooth (need demo too thick to scan) Ø https://vmicro.iusm.iu.edu/virtual_h/msci_130_5.html Junqueira Ø Fig. 15-10, 15-11, 15-12 Explain the relationship of ameloblasts and odontoblasts to the formation of enamel and dentine. Which layer disappears before eruption of the tooth and which layer persists? Notes The Digestive System Part I The digestive system consists of a long muscular tube, extending from mouth to anus, and a large number of associated glands which secrete substances that aid food digestion. The digestive tube is generally made up of four structurally and functionally distinct layers: the mucosa, the submucosa, the muscularis and the serosa. The mucosa, which is in contact with the contents of the lumen, is constructed to resist abrasion and to perform secretory and absorptive functions. The muscular layer which serves to propel the food through the tube is attached to the mucosa by way of the submucosa, a loose connective tissue layer. The serosa is called the adventitia when it is not covered by mesothelium. The serosa or adventitia carries blood vessels and nerves into the wall of the digestive tract. Objectives v Recognize the major features histological and physiological features of oral mucosa v Understand the relationship between structure and function in the esophagus v Recognize specific cell types in the lining of the stomach and their roles Electron micrograph - Fig. 15-22 Parietal cell Terms Lip Oral Mucosa Skin The oral (or buccal) cavity contains structures for ingestion and fragmentation of food, resulting in formation of a bolus of food for swallowing. We have already studied teeth. In this lab note the abundance of skeletal muscle and small salivary glands in the lip. The skin on the external surface merges into the nonkeratinized, stratified squamous epithelium of the oral mucosa on the internal surface. Slide Ø 35: Lip https://vmicro.iusm.iu.edu/virtual_h/msci_67_5.html Junqueira Ø Fig. 15-3 What are the major differences between oral mucosa and skin? Soft Palate Oral Mucosa Stratified Squamous (non-keratinized) Epithelium Nasal Mucosa Pseudostratified Ciliated Columnar Epithelium Mucous Glands Stratified squamous (non-keratinized) epithelium lines the oral surface of the soft palate and interdigitates with the lamina propria. The soft palate contains mucous glands that secrete their product into the oral cavity. Slide Ø 37: Soft Palate https://vmicro.iusm.iu.edu/virtual_h/464_37b.html Why would you expect that the epithelia lining the soft palate and the nasal cavity are so different? Esophagus Mucosa Epithelium Stratified Squamous (non-keratinzed) Epithelium Lamina Propria Muscularis Mucosae Submucosa Esophageal Mucous Glands Muscularis Inner Circular Layer Outer Longitudinal Layer Adventitia Slides Ø 40: Esophagus https://vmicro.iusm.iu.edu/virtual_h/msci_43_5.html Ø 2T: Esophagus https://vmicro.iusm.iu.edu/virtual_h/66_bl_5.html Junqueira Ø Fig. 15-14 What does the histology of the esophagus tell you about the protective functions of this organ? What type of muscle do you see in slides of esophagus and what does this tell you about the level from which the biopsy was taken? Gastro-esophageal Junction Esophagus (portion) Stratified Squamous (non-keratinzed) Epithelium Stomach (portion) Simple Columnar Epithelium Slide Ø 41a: Gastro-esophageal Junction https://vmicro.iusm.iu.edu/virtual_h_nw/nw_hist_1_124.html Junqueira Ø Fig. 15-17 Stomach Mucosa Gastric Pits Gastric Glands Neck Mucous Cell Parietal Cell Peptic Cell Lamina Propria Muscularis Mucosa Submucosa Muscularis Inner Oblique Layer Middle Circular Layer Outer Longitudinal Layer Slide Ø 43a: Stomach, body and pylorus https://vmicro.iusm.iu.edu/virtual_h/msci_101_5.html Junqueira Ø Figs. 15-18 through 15-24 What is the function of each epithelial cell type in the stomach? Why do you suppose most of these cells are protected down inside the gastric pits/glands? Stomach Gastric Pits Pyloric Glands Slides Ø 42: Stomach, Pyloric Region https://vmicro.iusm.iu.edu/virtual_h/464_42b.html Junqueira Ø Fig. 15-19 What is the functional significance of the main difference between the glands in the pylorus and in the rest of the stomach? Notes The Digestive System Part II The digestive tract continues from the stomach through the small and large intestines or bowels. The small intestine is a long organ with three regions along its length: the duodenum, the jejunum, and the ileum. Except for specialized structures that are present, such as Brunner’s mucous glands in the duodenum and Peyer’s patches in the ileum, all three regions of the small intestine are rather similar histologically and all are involved primarily in food digestive and in absorbing the products of digestion. Objectives v Understand the structural basis of absorption in the small intestine v Recognize the histological and functional differences between the small and large intestines Electron Micrographs - Fig. 15-28 and 15-29 o Enterocytes Fig. 15-31 o Endocrine cells Terms Gastroduodenal Junction Brunner’s Glands Pyloric Sphincter It is important to note the differences in the mucosa between the stomach and the small intestine. Slide Ø 5a: Gastroduodenal Junction https://vmicro.iusm.iu.edu/virtual_h/464_5b.html Junqueira Ø Fig. 15-34 What is lacking in the mucosa of the duodenum compared to that of the stomach? Duodenum Mucosa Simple Columnar Epithelium Villi Enterocytes Microvilli Goblet Cell Intestinal Gland Lacteals Muscularis Mucosae Submucosa Brunner’s Gland Muscularis Inner Circular Layer Outer Longitudinal Layer Serosa Slide Ø 43: Duodenum https://vmicro.iusm.iu.edu/virtual_h/msci_04_5.html Ø Junqueira Ø Figs. 15-25, 15-26, and 15-28 Describe the process by which enterocytes and goblet form, migrate, and eventually disappear from the surface of villi. Brunner’s glands supplement what other glands? Lacteals are an example of what structure studied earlier in the course? What is the specific function of lacteals in villi? Ileum Plicae Circularis (only on 46) Mucosa Simple Columnar Epithelium Goblet Cell Enterocyte Crypts of Lieberkühn Paneth Cell (only on 46) Mitotic cell Lamina Propria Lacteals Villi Peyer’s Patches (only on 45) Submucosa Muscularis Inner Circular Layer Outer Longitudinal Layer Serosa Note the some examples of Slide 45 contain roundworms! Lacteals can be found in the lamina propria of villi. Slide Ø 45: Ileum https://vmicro.iusm.iu.edu/virtual_h/464_45b.html Ø 46: Ileum https://vmicro.iusm.iu.edu/virtual_h/msci_21_5.html Junqueira Ø Figs. 15-27, 15-30, and 15-33 What is the function of the Paneth cells? What is the function of the muscularis mucosae in the ileum? Colon Mucosa Simple Columnar Epithelium Simple Tubular Glands (Colonic) Lamina Propria Muscularis Mucosae Submucosa Muscularis Inner Circular Layer Outer Longitudinal Layer Serosa Slide Ø 48a: Colon https://vmicro.iusm.iu.edu/virtual_h/464_48b.html Ø https://vmicro.iusm.iu.edu/virtual_h/msci_06_5.html Ø Junqueira Ø Figs. 15-36 through 15-38 Indicate three histological features of the colon which clearly pertain to its function. Notes Digestive Glands and Liver The large number of glands associated with the digestive canal range from unicellular components such as goblet cells and small tubuloalveolar units residing in the mucosa to very large separate organs such as the pancreas and liver. Although their secretions can be quite dissimilar, they all function to promote the digestive process by imparting enzymes or mucus into the ingested food. Bile, the exocrine secretion of the liver, is stored and concentrated in another organ, the gallbladder. Objectives v to recognize and understand the difference between serous and mucous acini in salivary glands v to understand histological and functional differences between the salivary glands and the exocrine pancreas v to understand the microscopic anatomy of the liver and how the arrangement of cells in this organ relates to the diverse functions of the liver Electron Micrographs - Figs. 16-15 and16-16 o Liver • Hepatocytes • Space of Disse • Microvilli • Lysosomes Terms Parotid Gland Serous Acini Serous Cell Slide Ø 50: Parotid gland https://vmicro.iusm.iu.edu/virtual_h/msci_132_5.html Junqueira Ø Figs. 16-1 through 16-3 What is the general function of serous glands? Salivary Gland Serous Acini Mucous Acini Serous Demilunes Slide Ø 51: Submandibular Gland https://vmicro.iusm.iu.edu/virtual_h/msci_72_5.html Ø 3a: Sublingual Gland https://vmicro.iusm.iu.edu/virtual_h/464_3b.html Junqueira Ø Figs. 16-1 through 16-6 What is the usual function of mucus? Pancreas Acini Acinar Cell Intercalated Duct Interlobular Duct Slides Ø 53: Pancreas https://vmicro.iusm.iu.edu/virtual_h/044_bl_5.html Ø https://vmicro.iusm.iu.edu/virtual_h/msci_154_5.html Junqueira Ø Figs. 16-7 through 16-10 Indicate one secreted factor of intercalated ducts. Liver Septa (Slide 55) Lobules Central Vein Portal Tract Portal Triad Branch of Hepatic Portal Vein Branch of Hepatic Artery Bile Ductule Simple Cuboidal Lining Hepatic Plate Hepatocytes Hepatic Sinusoid (Slide 56 and Slide 59) Endothelial Lining Slide Ø 59: Liver https://vmicro.iusm.iu.edu/virtual_h/msci_141_5.html Ø 56: Liver https://vmicro.iusm.iu.edu/virtual_h/msci_29_5.html Ø 6a: Liver pig https://vmicro.iusm.iu.edu/virtual_h/464_55b.html Junqueira Ø Figs. 16-11 through 16-19 How does the organization of hepatocytes as plates facilitate their functioning? Where is most of the connective tissue of the liver located? Where exactly does blood entering a liver lobule from the hepatic artery and the portal vein mix? Gall Bladder Mucosa Simple Columnar Epithelium Submucosa Slide Ø 58: Gall Bladder https://vmicro.iusm.iu.edu/virtual_h/msci_105_5.html Junqueira Ø Fig. 16-20 and 16-21 How does the histology of this mucosa facilitate the gall bladder’s function? Notes The Respiratory System The main function of the respiratory system is the transferring of gases between the air and the blood. The system is comprised of tubes and highly branched channels which terminate in dead-end sacs where gas transfer occurs. Air brought into the body is first conditioned and filtered in the first part of the respiratory system, the conducting portion, which extends from the nasal cavity to the bronchioles. The second part of the system, the respiratory portion, consists of the respiratory bronchioles and alveoli are involved with gas exchange. Objectives v Understand the general organization of the respiratory system and recognize LM preparations of the various regions v Understand the structure and functional significance of respiratory alveoli v Recognize the different cell types in an alveolus Electron Micrographs - Fig. 17-15 o Alveolar Walls • Type I pneumocytes • Capillary Fig. 17-16 o Type II pneumocyte - Terms Trachea Tracheal Rings Hyaline Cartilage Trachealis Muscle Mucosa Respiratory Epithelium (PCCE) Ciliated Cell Goblet Cell Basement Membrane Submucosa Sero-Mucous Gland Ø Slide60: Trachea https://vmicro.iusm.iu.edu/virtual_h/002_bl_5.html Ø https://vmicro.iusm.iu.edu/virtual_h/140_bl_5.html Junqueira Ø Figs. 17-5 through 17-7 What is the function of the rings of hyaline cartilage? Why are they made of hyaline rather than elastic cartilage? What is the muscle type in the trachealis muscle and what function does it serve here? How do the ciliated cells and the goblet cells work together in a protective function? Lung Bronchi Branch of Pulmonary Artery (only 61) Bronchioles Simple Columnar to Cuboidal Epithelium Smooth Muscle Goblet Cell Terminal Bronchiole Simple Cuboidal Epithelium Smooth Muscle Respiratory Bronchiole Simple Cuboidal Epithelium Alveoli Alveolar Duct Simple Squamous Epithelium Alveolar Sac Simple Squamous Epithelium Alveoli Type I Pneumocyte (only 61) Type II Pneumocyte (only 61) Dust Cell (Macrophage) (only 61) Interalveolar Septa Capillary (only 61) Endothelial Cell (only 61) Slide Ø 61: Lung https://vmicro.iusm.iu.edu/virtual_h/97_bl_5.html Ø 62: Lung https://vmicro.iusm.iu.edu/virtual_h/98_bl_5.html Junqueira Ø Figs. 17-7 through 17-14 Indicate the function of the cells that air contacts as it moves deeper and deeper into the lung? What is the major histological difference between the conducting and the respiratory portions of the airway? What is the major chemical property of surfactant? Compare and contrast type I and type II pneumocytes. What one alveolar cell type is often critically lacking in premature infants, causing respiratoru distress syndrome? Notes The Urinary System The urinary system consists of the kidneys, ureters, bladder and urethra and is responsible for the important bodily function of soluble waste production, storage and elimination. The waste substances are produced in the kidney as blood filtrates, transported via the ureters to the bladder where it is stored and eventually eliminated through the urethra. This process also results in the salvaging of large amounts of water, sugars and ions from the blood filtrate which are returned to the blood. In addition, the kidneys play a role in controlling systemic blood pressure by the secretion of renin. Objectives v Recognize and distinguish the various regions of the urinary system v Understand the blood supply and significance of blood flow within the kidney v Understand the structural and functional organization of the kidney and its nephrons v Understand the structural basis and physiological basis of blood filtration in nephrons v Distinguish the different regions of a nephron and their functional significance Electron Micrographs Study all of the EMs in Chapter 19 of Junqueira and compare the EMs to the LMs and to the corresponding structures on your slides. In both Figure 19-5 and Figure 19-6 recognize and understand the following terms. Podocytes Primary foot processes Secondary foot processes Filtration slits Glomerular basement membrane Endothelial fenestrations What are the driving forces that cause fluid to move from the capillary to Bowman’s space? The dialysis tubing in a kidney dialysis machine is analogous to what part of the renal corpuscle? Terms Kidney Cortex Renal Corpuscle Glomerulus Bowman’s Capsule Bowman’s Space Medullary Rays Proximal Convoluted Tubule Distal Convoluted Tubule Juxtaglomerular Apparatus (only 64) Macula Densa (only 64) Afferent Arteriole Medulla Thin Limb of the Loop of Henle Thick Limb of the Loop of Henle Vasa Recta (capillaries) Collecting Duct Renal Papillae (only on 65) Ducts of Bellini (only on 65) Slide Ø 64: Kidney https://vmicro.iusm.iu.edu/virtual_h/msci_144_5.html Ø 65: Kidney trichrome (monkey) https://vmicro.iusm.iu.edu/virtual_h/msci_14_5.html Ø Kidney Rat https://vmicro.iusm.iu.edu/virtual_h/msci_111_5.html Junqueira Ø Figs. 19-2 through 19-14 Name a simple squamous structure in the cortex. How does the structure of the proximal convoluted tubule cells relate to their function? Compare and contrast the cells of the proximal convoluted tubule and the distal convoluted tubule. What is the general function of the loop of Henle? Ureter Mucosa Transitional Epithelium Lamina Propria Muscularis Adventitia Slide Ø 69: Ureter https://vmicro.iusm.iu.edu/virtual_h/msci_16_5.html Junqueira Ø Fig. 19-15 What does the structure of the ureter’s muscularis suggest about this layer’s function? Urinary Bladder Mucosa Transitional Epithelium Lamina Propria Muscularis Adventitia (or serosa) Examine Slides Ø 70: Urinary Bladder (distended) https://vmicro.iusm.iu.edu/virtual_h/464_70b.html Ø 71: Urinary Bladder (empty) https://vmicro.iusm.iu.edu/virtual_h/464_71b.html Ø Human Bladder https://vmicro.iusm.iu.edu/virtual_h/msci_118_5.html Junqueira Ø Figs. 19-16, 19-17 What is the function of this muscularis? Notes The Endocrine System The organs usually grouped together as the endocrine system represent many structures with a great deal of morphological and functional diversity. The fact that they are grouped together reflects primarily the fact that they all secrete directly into the extracellular space for uptake by the blood stream, rather than delivering their products into ducts for transport to other sites, as in the exocrine glands. Endocrine glands may be large, distinct organs, such as those to be studied here, or scattered groups of cells, such as the pancreatic islets, or individual cells, such as those found in the mucosa of the digestive system. A structural feature common to all endocrine tissues is a very rich vascular supply. Furthermore, in spite of having origins from diverse kinds of tissues, almost all endocrine glands are structurally epithelial in appearance, i.e., they are composed of sheets, tubes, columns or clusters of closely contiguous cells. A less universal feature of endocrine cells is a content of granules suggesting the secretory function of the cells. Objectives v Understand the functional characteristics of endocrine cells and organs v Be able to distinguish the major endocrine glands in LM v Distinguish the regions, zones, and most important specific cells in the pituitary gland, adrenal glands, thyroid gland, parathyroid gland, and the pancreatic islets. Terms Pituitary Gland (Hypophysis) Anterior Pituitary Pars Distalis Basophils Acidophils Chromophobes Pars Intermedia Rathke’s Pouch (remnants) Posterior Pituitary Pars Nervosa Pituicytes Axons Slide Ø 10T: Pituitary Gland https://vmicro.iusm.iu.edu/virtual_h/msci_122_5.html Ø 34: Pituitary Gland https://vmicro.iusm.iu.edu/virtual_h/128_bl_5.html Ø Anterior Pituitary https://vmicro.iusm.iu.edu/virtual_h/msci_103_5.html Ø Junqueira Ø Figs. 20-1 through 20-11 Name two basophils and two acidophils and give the target cells for their secretions. The staining property of chromophobes is believed to have what functional significance? Hormones stored in the axons of the pars nervosa are synthesized in cell bodies located where? Adrenal Gland Capsule Cortex Zona Glomerulosa Zona Fasciculata Zona Reticularis Venous Sinuses Medulla Chromaffin Cells Slide Ø 33: Adrenal Gland https://vmicro.iusm.iu.edu/virtual_h/msci_63_5.html Ø https://vmicro.iusm.iu.edu/virtual_h/msci_102_5.html Ø adrenal rabbit: https://vmicro.iusm.iu.edu/virtual_h/msci_35_5.html Junqueira Ø Figs. 20-12 through 20-16 Compare and contrast the 3 zones of the adrenal cortex. What is the embryological origin of the adrenal medulla? Thyroid Gland Follicles Follicular Cell Colloid Parafollicular Cell Slides Ø 32: Thyroid Gland (Mallory stain) https://vmicro.iusm.iu.edu/virtual_h/msci_23_5.html Ø Thyroid and Parathyroid https://vmicro.iusm.iu.edu/virtual_h_nw/nw_hist_1_195.html Junqueira Ø Figs. 20-18 through 20-21 In what sense can thyroid follicles be considered both exocrine and endocrine? Parathyroid Gland Capsule Principal Cell (Chief) Oxyphil Cell Slide Ø 90: Parathyroid Gland https://vmicro.iusm.iu.edu/virtual_h/msci_69_5.html Ø Junqueira Ø Figs. 20-22, 20-23 Principal cells of this gland can be considered antagonists to what other cells? Pancreas Islets of Langerhans Slide Ø 53: Pancreas https://vmicro.iusm.iu.edu/virtual_h/044_bl_5.html Junqueira Ø Fig. 20-17 What are the two important pancreatic hormones with opposite effects on glucose metabolism? The other hormones made in the islets are similar to those by what other endocrine cells? Notes The Male Reproductive System The male reproductive system is responsible for the production, storage and delivery of sperm, the male gametes. It consists of the testes, where gamete production occurs, a system of ducts, the site of gamete maturation and passage to the exterior, and several associated glands which provide the fluid medium for transport and nourishment for the gametes. It is important to recognize and understand the cell types within the seminiferous tubules of the testes that represent the different stages of meiosis and sperm production, as well as the secretory cells outside and inside these tubules that support the process of spermatogenesis. Objectives v Recognize and understand the structure of the testis under the light microscope v Understand the process of spermatogenesis and recognize the major stages of this process v Understand the functions and structural features of the major regions of the male reproductive ducts v Recognize and know the function of the seminal vesicles and prostate gland v Recognize structures in the penis and understand how these structures contribute to its function Electron Micrographs and diagram - Fig. 21-8 o Spermatozoan - Fig. 21-5 o Sertoli cell • Spermatogonia • Spermatocytes • Spermatids • Spermatozoa Terms Testis Tunica Albuginea Seminiferous Tubules Spermatagonia Primary Spermatocyte Spermatids Spermatozoa Sertoli Cell (nuclei) Leydig Cells (Interstitial) Rete Testis (only on 72) Epididymis (only on 72) Stereocilia (only on 72) Ductus Epididymis (only on 72) Slide Ø 11T: Testis https://vmicro.iusm.iu.edu/virtual_h/119_bl_5.html Ø 72: Testis and Epididymis (Dog) https://vmicro.iusm.iu.edu/virtual_h/msci_155_5.html Junqueira Ø Figs. 21-3 through 21-11 Why are the secondary spermatocytes rare? What is the longest stage of spermatogenesis? Indicate three functions of Sertoli cells. Ductus Deferens (Vas Deferens) Pseudostratified Ciliated Columnar Epithelium Lamina Propria Muscularis Note that the muscularis has three layers and is very thick. Slide Ø 73: Ductus Deferens https://vmicro.iusm.iu.edu/virtual_h/msci_53_5.html Junqueira Ø Fig. 21-12 What does the muscularis tell you about the function of the vas deferens? Seminal Vesicle Mucosa Simple Columnar Epithelium Muscularis The mucosa is highly folded and the muscularis is very thick. Slides Ø 74: Seminal Vesicle https://vmicro.iusm.iu.edu/virtual_h/124_bl_5.html Junqueira Ø Figs. 21-13, 21-14 What components of semen do the seminal vesicles produce? Prostate Gland Prostatic Glands Corpora Amylacea The individual glands have a molded mucosa whose epithelium transition from cuboidal to pseudostratified. Slides Ø 75: Prostate Gland https://vmicro.iusm.iu.edu/virtual_h/msci_47_5.html Ø https://vmicro.iusm.iu.edu/virtual_h/95_bl_5.html Junqueira Ø Figs. 21-15, 21-16 How does benign prostate hyperplasia, BPH, which is common in older men, cause medical problems? Penis Corpora Cavernosa Helicine Arteries Erectile Tissue (cavernous) Corpus Spongiosum Urethra Slide Ø 76: Penis https://vmicro.iusm.iu.edu/virtual_h/109_bl_5.html Ø Penis https://vmicro.iusm.iu.edu/virtual_h_nw/nw_hist_1_170.html Junqueira Ø Figs. 21-17 through 21-19 What specific cell type(s) in the penis are acted on by “erectile dysfunction” drugs such as Viagra? Notes The Female Reproductive System Structures in the female reproductive system are specialized for the production, movement, fertilization and maintenance of the female gamete, the egg or ovum, and for the reception of sperm. In studying the system, one must keep in mind the major cyclical influence of hormones on various parts of the female reproductive system, which results in a dynamic and constantly changing morphology. Study the diagram in figure 19.7 of Junqueira for a useful summary of the development of ovarian follicles and the hormones involved in this process. Objectives v Understand and recognize the overall organization of the ovary v Recognize developing oocytes and their associated tissues in the ovary v Understand the histological changes and their physiological significance during the developmental process of oogenesis, ovulation, and corpus luteum formation v Recognize and understand the functional significance of tissues in the fallopian tubes (oviducts) v Recognize the layers of the uterine wall and know how these change during the menstrual cycle Terms Ovary Tunica Albuginea Germinal Epithelium (Serosa) Primordial Follicle Primary Oocyte Follicular Cell (Granulosa) Primary Follicle Primary Oocyte Follicular Cell (Granulosa) Zona Pellucida Basement Membrane Thecae Folliculi Secondary Follicle Primary Oocyte Follicular Cell (Granulosa) Zona Pellucida Basement Membrane Theca Interna Theca Externa Antrum Mature (Graafian) Follicle Follicular Cell (Graafian) Theca Interna Theca Externa Antrum Cumulus Oophorus Corona Radiata Oocyte Atretic Follicles Slide Ø 1: Ovary https://vmicro.iusm.iu.edu/virtual_h/61_bl_5.html Ø 1a: Ovary rabbit https://vmicro.iusm.iu.edu/virtual_h/464_1b.html Ø Junqueira Ø Figs. 22-1 through 22-9 How does the germinal epithelium differ from most mesothelia in the body? When do primordial follicles develop? What is the major function of granulosa cells and the significance of the zona pellucida? What types of cells are present in the theca interna? How exactly does the antrum relate to the process of ovulation? What is the difference between the cumulus Oophorus and the corona radiata and what exactly is released from the ovary at ovulation? Ovary Corpus Luteum Theca Luteal Cell Granulosa Luteal Cell Slide Ø 79: Corpus Luteum https://vmicro.iusm.iu.edu/virtual_h/058_bl_5.html Ø Junqueira Ø Fig. 22-10 What two hormones do the two endocrine cell types in the corpus luteum synthesize? Ovary (Postmenopausal) Corpus Albicans Slides Ø 78: Postmenopausal Ovary https://vmicro.iusm.iu.edu/virtual_h/464_78b.html Junqueira Ø Fig. 22-11 Where did the corpus albicans come from? Fallopian Tube (Oviduct, Fallopian Tube) Mucosa Simple Columnar Cells Lamina Propria Muscularis Serosa Slide Ø 80: Fallopian Tube https://vmicro.iusm.iu.edu/virtual_h/msci_145_5.html Junqueira Ø Fig. 22-12 What two histological features of the oviduct relate to the movement of its contents? Uterus Endometrium Stratum Functionalis Stratum Basalis Spiral Arteries Myometrium Perimetrium (Serosa) Slide Ø 81: Uterus monkey https://vmicro.iusm.iu.edu/virtual_h/001_bl_5.html Ø Uterus endometrium proliferative https://vmicro.iusm.iu.edu/virtual_h_nw/nw_hist_1_177.html Ø Uterus endometrium secretory https://vmicro.iusm.iu.edu/virtual_h_nw/nw_hist_1_178.html Ø Uterus repair https://vmicro.iusm.iu.edu/virtual_h_nw/nw_hist_1_176.html Junqueira Ø Figs. 22-13 through 22-17 Describe the major changes in the endometrium during the menstrual cycle. What exactly is lost during menstruation? Notes