Survey
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
Chapter 4: Organization at the Tissue Level Tissues are collections of cells that serve a collective purpose Collections of tissues form organs Socrative app – course 701439 ?1. What is your name ? 2. Name 4 types of tissue. © 2012 Pearson Education, Inc. An Introduction to Tissues Tissues Structures with discrete structural and functional properties Tissues in combination form organs, such as the heart or liver Organs can be grouped into 11 organ systems ? 3. List the 11 organ systems © 2012 Pearson Education, Inc. 4-1 Four Types of Tissue Tissue Are collections of cells and cell products that perform specific, limited functions Four types of tissue 1. Epithelial tissue 2. Connective tissue 3. Muscle tissue 4. Neural tissue © 2012 Pearson Education, Inc. 4-1 Four Types of Tissue Epithelial Tissue Covers exposed surfaces Lines internal passageways Forms glands Connective Tissue Fills internal spaces Supports other tissues Transports materials Stores energy © 2012 Pearson Education, Inc. 4-1 Four Types of Tissue Muscle Tissue Specialized for contraction Skeletal muscle, heart muscle, and walls of hollow organs Neural Tissue Carries electrical signals from one part of the body to another © 2012 Pearson Education, Inc. 4-2 Epithelial Tissue Epithelia Layers of cells covering internal or external surfaces Glands Structures that produce secretions © 2012 Pearson Education, Inc. 4-2 Epithelial Tissue Characteristics of Epithelia Cellularity (cell junctions) ** Cell membrane features Polarity (apical and basal surfaces) ** think apex (top; peak) and basement (below) Attachment (basement membrane or basal lamina) Avascularity Without blood vessels Regeneration © 2012 Pearson Education, Inc. Figure 4-1 The Polarity of Epithelial Cells Cilia Microvilli Apical surface Golgi apparatus Nucleus Mitochondria Basement membrane Basolateral surfaces © 2012 Pearson Education, Inc. 4-2 Epithelial Tissue Functions of Epithelial Tissue 1. Provide Physical Protection 2. Control Permeability 3. Provide Sensation 4. Produce Specialized Secretions (glandular epithelium) © 2012 Pearson Education, Inc. 4-2 Epithelial Tissue Specializations of Epithelial Cells 1. Move fluids over the epithelium (protection) 2. Move fluids through the epithelium (permeability) 3. Produce secretions (protection and messengers) © 2012 Pearson Education, Inc. ? 4. What are 4 functions of epithelial cell? © 2012 Pearson Education, Inc. 4-2 Epithelial Tissue Intercellular Connections Support and communication CAMs (cell adhesion molecules) Intercellular cement Transmembrane proteins Proteoglycans Hyaluronan (hyaluronic acid) Glycosaminoglycans © 2012 Pearson Education, Inc. 4-2 Epithelial Tissue Intercellular Connections Cell junctions Form bonds with other cells or extracellular material 1. Tight junctions 2. Gap junctions 3. Desmosomes © 2012 Pearson Education, Inc. Figure 4-2 Cell Junctions Interlocking junctional proteins Tight junction Tight junction Adhesion belt Terminal web Spot desmosome Adhesion belt Gap junctions Hemidesmosome Embedded proteins (connexons) Clear layer Dense layer Intermediate filaments Basement membrane Dense area Cell adhesion molecules (CAMs) Proteoglycans © 2012 Pearson Education, Inc. Figure 4-2a Cell Junctions Tight junction Adhesion belt Terminal web Spot desmosome Gap junctions Hemidesmosome This is a diagrammatic view of an epithelial cell, showing the major types of intercellular connections. © 2012 Pearson Education, Inc. 4-2 Epithelial Tissue Tight Junctions Between two plasma membranes Adhesion belt attaches to terminal web Prevents passage of water and solutes Isolates wastes in the lumen (open space down the center of a tube) © 2012 Pearson Education, Inc. Figure 4-2b Cell Junctions Interlocking junctional proteins Tight junction Terminal web Adhesion belt A tight junction is formed by the fusion of the outer layers of two plasma membranes. Tight junctions prevent the diffusion of fluids and solutes between the cells. A continuous adhesion belt lies deep to the tight junction. This belt is tied to the microfilaments of the terminal web. © 2012 Pearson Education, Inc. 4-2 Epithelial Tissue Gap Junctions Allow rapid communication Are held together by channel proteins (junctional proteins, connexons) Allow ions to pass Coordinate contractions in heart muscle © 2012 Pearson Education, Inc. Figure 4-2c Cell Junctions Embedded proteins (connexons) Gap junctions permit the free diffusion of ions and small molecules between two cells. © 2012 Pearson Education, Inc. 4-2 Epithelial Tissue Desmosomes CAMs, dense areas, and intercellular cement Spot desmosomes (“spot weld”) Tie cells together Allow bending and twisting Hemidesmosomes Attach © 2012 Pearson Education, Inc. cells to the basal lamina Figure 4-2d Cell Junctions Intermediate filaments Cell adhesion molecules (CAMs) Dense area Proteoglycans A spot desmosome ties adjacent cells together. © 2012 Pearson Education, Inc. Figure 4-2e Cell Junctions Clear layer Dense layer Hemidesmosomes attach a cell to extracellular structures, such as the protein fibers in the basement membrane. © 2012 Pearson Education, Inc. Basement membrane ? 5. What types of intercellular connections are used to ‘glue’ epithelial cells together? © 2012 Pearson Education, Inc. 4-2 Epithelial Tissue Attachment to the Basement Membrane Clear layer (lamina lucida) Thin layer Secreted by epithelia Barrier to proteins Dense layer (lamina densa) Thick fibers Produced by connective tissue Strength and filtration © 2012 Pearson Education, Inc. 4-2 Epithelial Tissue Epithelial Maintenance and Repair Epithelia are replaced by division of germinative cells (stem cells) Near basement membrane © 2012 Pearson Education, Inc. 4-3 Classification of Epithelia Singular = Epithelium; Plural = Epithelia Classes of Epithelia 1. 2. Based on shape Squamous epithelia — thin and flat Cuboidal epithelia — square shaped Columnar epithelia — tall, slender rectangles Based on layers Simple epithelium — single layer of cells Stratified epithelium — several layers of cells © 2012 Pearson Education, Inc. Table 4-1 Classifying Epithelia © 2012 Pearson Education, Inc. Table 4-1 Classifying Epithelia © 2012 Pearson Education, Inc. 4-3 Classification of Epithelia Squamous Epithelia Simple squamous epithelium Mesothelium Absorption and diffusion Lines body cavities Endothelium Lines heart and blood vessels © 2012 Pearson Education, Inc. Figure 4-3a Squamous Epithelia Simple Squamous Epithelium LOCATIONS: Mesothelia lining ventral body cavities; endothelia lining heart and blood vessels; portions of kidney tubules (thin sections of nephron loops); inner lining of cornea; alveoli of lungs FUNCTIONS: Reduces friction; controls vessel permeability; performs absorption and secretion Cytoplasm Nucleus Connective tissue Lining of peritoneal cavity © 2012 Pearson Education, Inc. LM 238 4-3 Classification of Epithelia Squamous Epithelia Stratified squamous epithelium Protects against attacks Keratin protein adds strength and water resistance © 2012 Pearson Education, Inc. Figure 4-3b Squamous Epithelia Stratified Squamous Epithelium LOCATIONS: Surface of skin; lining of mouth, throat, esophagus, rectum, anus, and vagina FUNCTIONS: Provides physical protection against abrasion, pathogens, and chemical attack Squamous superficial cells Stem cells Basement membrane Connective tissue Surface of tongue © 2012 Pearson Education, Inc. LM 310 4-3 Classification of Epithelia Cuboidal Epithelia Simple cuboidal epithelium Secretion and absorption Stratified cuboidal epithelia Sweat ducts and mammary ducts © 2012 Pearson Education, Inc. Figure 4-4a Cuboidal and Transitional Epithelia Simple Cuboidal Epithelium LOCATIONS: Glands; ducts; portions of kidney tubules; thyroid gland Connective tissue FUNCTIONS: Limited protection, secretion, absorption Nucleus Cuboidal cells Basement membrane Kidney tubule © 2012 Pearson Education, Inc. LM 650 Figure 4-4b Cuboidal and Transitional Epithelia Stratified Cuboidal Epithelium LOCATIONS: Lining of some ducts (rare) FUNCTIONS: Protection, secretion, absorption Lumen of duct Stratified cuboidal cells Basement membrane Nuclei Connective tissue Sweat gland duct © 2012 Pearson Education, Inc. LM 500 ? 6. What are the major classifications of epithelial cells? *** pg 116, 117*** © 2012 Pearson Education, Inc. 4-3 Classification of Epithelia Transitional Epithelium Tolerates repeated cycles of stretching and recoiling and returns to its previous shape without damage Appearance changes as stretching occurs Situated in regions of the urinary system (e.g., urinary bladder) © 2012 Pearson Education, Inc. Figure 4-4c Cuboidal and Transitional Epithelia Transitional Epithelium LOCATIONS: Urinary bladder; renal pelvis; ureters FUNCTIONS: Permits expansion and recoil after stretching Epithelium (relaxed) Basement membrane Empty bladder Connective tissue and smooth muscle layers LM 400 Epithelium (stretched) Full bladder Urinary bladder © 2012 Pearson Education, Inc. Basement membrane Connective tissue and smooth muscle layers LM 400 LM 400 4-3 Classification of Epithelia Columnar Epithelia Simple columnar epithelium Pseudostratified columnar epithelium Absorption and secretion Cilia movement Stratified columnar epithelium Protection © 2012 Pearson Education, Inc. Figure 4-5a Columnar Epithelia Simple Columnar Epithelium LOCATIONS: Lining of stomach, intestine, gallbladder, uterine tubes, and collecting ducts of kidneys FUNCTIONS: Protection, secretion, absorption Microvilli Cytoplasm Nucleus Intestinal lining © 2012 Pearson Education, Inc. Basement membrane Loose connective tissue LM 350 Figure 4-5b Columnar Epithelia Pseudostratified Ciliated Columnar Epithelium LOCATIONS: Lining of nasal cavity, trachea, and bronchi; portions of male reproductive tract Cilia Cytoplasm FUNCTIONS: Protection, secretion, move mucus with cilia Nuclei Basement membrane Trachea © 2012 Pearson Education, Inc. Loose connective tissue LM 350 Figure 4-5c Columnar Epithelia Stratified Columnar Epithelium LOCATIONS: Small areas of the pharynx, epiglottis, anus, mammary glands, salivary gland ducts, and urethra FUNCTION: Protection Lumen Loose connective tissue Deeper basal cells Superficial columnar cells Lumen Cytoplasm Nuclei Salivary gland duct © 2012 Pearson Education, Inc. Basement membrane LM 175 4-3 Classification of Epithelia Glandular Epithelia Endocrine glands Release hormones Into interstitial fluid No ducts (adrenal glands, ovaries, testes) Exocrine glands Produce secretions Onto epithelial surfaces Through ducts (sweat, salivary, mammary) © 2012 Pearson Education, Inc. 4-3 Classification of Epithelia Glandular Epithelia Modes of Secretion 1. Merocrine secretion 2. Apocrine secretion 3. Holocrine secretion © 2012 Pearson Education, Inc. 4-3 Classification of Epithelia Merocrine Secretion Produced in Golgi apparatus Released by vesicles (exocytosis) For example, sweat glands Apocrine Secretion Produced in Golgi apparatus Released by shedding cytoplasm For example, mammary glands © 2012 Pearson Education, Inc. 4-3 Classification of Epithelia Holocrine Secretion Released by cells bursting, killing gland cells Gland cells replaced by stem cells For example, sebaceous glands © 2012 Pearson Education, Inc. 4-3 Classification of Epithelia Glandular Epithelia Types of Secretions Serous glands Mucous glands Watery secretions Secrete mucins Mixed exocrine glands Both serous and mucous © 2012 Pearson Education, Inc. 4-3 Classification of Epithelia Glandular Epithelia Gland Structure Unicellular glands Mucous (goblet) cells are the only unicellular exocrine glands Scattered among epithelia For example, in intestinal lining © 2012 Pearson Education, Inc. 4-3 Classification of Epithelia Gland Structure Multicellular glands 1. 2. 3. Structure of the duct Simple (undivided) Compound (divided) Shape of secretory portion of the gland Tubular (tube shaped) Alveolar or acinar (blind pockets) Relationship between ducts and glandular areas Branched (several secretory areas sharing one duct) © 2012 Pearson Education, Inc. Figure 4-7 A Structural Classification of Exocrine Glands SIMPLE GLANDS Duct Gland cells SIMPLE TUBULAR Examples: • Intestinal glands SIMPLE COILED TUBULAR Examples: • Merocrine sweat glands SIMPLE ALVEOLAR (ACINAR) Examples: • Not found in adult; a stage in development of simple branched glands © 2012 Pearson Education, Inc. SIMPLE BRANCHED TUBULAR Examples: • Gastric glands • Mucous glands of esophagus, tongue, duodenum SIMPLE BRANCHED ALVEOLAR Examples: • Sebaceous (oil) glands Figure 4-7 A Structural Classification of Exocrine Glands COMPOUND GLANDS COMPOUND TUBULAR Examples: • Mucous glands (in mouth) • Bulbo-urethral glands (in male reproductive system) • Testes (seminiferous tubules) © 2012 Pearson Education, Inc. COMPOUND ALVEOLAR (ACINAR) Examples: • Mammary glands COMPOUND TUBULOALVEOLAR Examples: • Salivary glands • Glands of respiratory passages • Pancreas