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Chapter 5 Tissues and Histology • Tissues - collections of similar WHAT??? and the substances surrounding them • Tissue classification based on structure of these, composition of nonstuff extracellular matrix, and this function • Major types of adult ones include – Epithelial – Connective – Muscle – Nervous • Histology: Microscopic Study of This – Biopsy: removal of t--- for diagnostic purposes – Autopsy: examination of organs of a dead body to determine cause of death Chapter 5 Tissues and Histology • Tissues - collections of similar cells and the substances surrounding them • Tissue classification based on structure of cells, composition of noncellular extracellular matrix, and cell function • Major types of adult tissues – E? – C? – M? – N? • Histology: Microscopic Study of Tissues – Biopsy: removal of tissues for diagnostic purposes – Autopsy: examination of organs of a dead body to determine cause of death Chapter 5 Tissues and Histology • Tissues - collections of similar cells and the substances surrounding them • Tissue classification based on structure of cells, composition of noncellular extracellular matrix, and cell function • Major types of adult tissues – Epithelial – Connective – Muscle – Nervous • Histology: M??????? Study of Tissues – Biopsy: removal of tissues for diagnostic purposes – Autopsy: examination of organs of a dead body to determine cause of death Chapter 5 Tissues and Histology • Tissues - collections of similar cells and the substances surrounding them • Tissue classification based on structure of cells, composition of noncellular extracellular matrix, and cell function • Major types of adult tissues – Epithelial – Connective – Muscle – Nervous • Histology: Microscopic Study of Tissues – Biopsy: removal of tissues for diagnostic purposes – Autopsy: examination of organs of a dead body to determine cause of death Embryonic Tissue • 3 major germ layers that form the embryonic disc (source of stem cells) – Endoderm • Inner layer • Forms lining of digestive tract and derivatives – Mesoderm • Middle layer • Forms tissues as such muscle, bone, blood vessels – Ectoderm • Outer layer • Forms skin and neuroectoderm I. E????? Tissue • Cellularity - Consists almost entirely of cells • Covers body surfaces, lines hollow organs, and forms glands – Outside surface of the body – Lining of digestive, respiratory and urogenital systems – Heart and blood vessels – Linings of many body cavities • Specialized cell contacts bind adjacent cells together • Avascular - no blood vessels • Regenerative -Replaces lost cells by cell division I. Epithelial Tissue • Cellularity - Consists almost entirely of ???? • Covers body s?????, lines hollow organs, and forms glands – Outside surface of the body – Lining of digestive, respiratory and urogenital systems – Heart and blood vessels – Linings of many body cavities • Specialized cell contacts bind adjacent cells together • Avascular - no blood vessels • Regenerative -Replaces lost cells by cell division I. Epithelial Tissue • Cellularity - Consists almost entirely of cells • Covers body surfaces, lines hollow organs, and forms glands – Outside surface of the body – Lining of digestive, respiratory and urogenital systems – Heart and blood vessels – Linings of many body cavities • Specialized cell contacts bind adjacent cells together • Avascular - no blood vessels • Regenerative -Replaces lost cells by cell division Functions of Epithelia • P?????? underlying structures; e.g., epithelium lining the mouth • Acting as barriers; e.g., skin • Permitting the passage of substances; e.g., cells lining air sacs in lungs and nephrons in kidney • S?????? substances; e.g., pancreatic cells • A?????? substances; e.g., lining of stomach and small intestine Functions of Epithelia • Protecting underlying structures; e.g., epithelium lining the mouth • Acting as barriers; e.g., skin • Permitting the passage of substances; e.g., cells lining air sacs in lungs and nephrons in kidney • Secreting substances; e.g., pancreatic cells • Absorbing substances; e.g., lining of stomach and small intestine Special Characteristics of Epithelia Figure 4.1 Classification of Epithelium • Number of layers of cells – S?????- one layer of cells. Each extends from basement membrane to the free surface – S?????????- more than one layer. – Pseudostratified- tissue appears to be stratified, but all cells contact basement membrane so it is in fact simple • Shape of cells – Sq???????- flat, scale-like – Cuboidal- about equal in height and width – Co???????- taller than wide Classification of Epithelium • Number of layers of cells – Simple- one layer of cells. Each extends from basement membrane to the free surface – Stratified- more than one layer. – Pseudostratified- tissue appears to be stratified, but all cells contact basement membrane so it is in fact simple • Shape of cells – Squamous- flat, scale-like – Cuboidal- about equal in height and width – Columnar- taller than wide Classifications of Epithelia Simple Squamous Epithelium Figure 4.3a Simple Cuboidal Epithelium Figure 4.3b Simple Columnar Epithelium Figure 4.3c Pseudostratified Ciliated Columnar Epithelium Figure 4.3d Stratified Epithelia • • • • Contain two or more layers of cells Regenerate from below Major role is protection Are named according to the shape of cells at apical layer Stratified Squamous Epithelium • Description – Many layers of cells – squamous in shape – Deeper layers of cells appear cuboidal or columnar – Thickest epithelial tissue – adapted for protection Stratified Squamous Epithelium • Specific types – Keratinized – contain the protective protein keratin • Surface cells are dead and full of keratin – Non-keratinized – forms moist lining of body openings Stratified Squamous Epithelium • Function – Protects underlying tissues in areas subject to abrasion • Location – Keratinized – forms epidermis – Non-keratinized – forms lining of esophagus, mouth, and vagina Stratified Squamous Epithelium Figure 4.3e Transitional Epithelium Figure 4.3h Epithelium: Glandular • A gland is one or more cells that makes and secretes an aqueous fluid • Two types of glands formed by infolding of epithelium: – Endocrine: no contact with exterior of body; ductless; produce hormones (pituitary, thyroid, adrenals, pancreas) – Exocrine: open to exterior of body via ducts (sweat, oil) • Exocrine glands classified either by structure or by the method of secretion • Classified by structure – Unicellular: goblet cells – Multicellular: sweat, oil, pituitary, adrenal Multicellular Exocrine Glands • Classified on the basis of types of ducts or mode of secretion • Types of ducts – Simple: ducts with few branches – Compound: ducts with many branches • If ducts end in tubules or sac-like structures: acini. Pancreas • If ducts end in simple sacs: alveoli. Lungs Name this type of Tissue • Most diverse and abundant tissue • Main classes – – – – tissue proper Cartilage Bone tissue Blood • Characteristics – Mesenchyme as their common tissue of origin (mesenchyme derived from mesoderm) – Varying degrees of vascularity – Nonliving extracellular matrix, consisting of ground substance and fibers – Cells are not as abundant nor as tightly packed together as in epithelium Connective Tissue • Most diverse and abundant tissue • Main classes – – – – Connective tissue proper C? B? B? • Characteristics – Mesenchyme as their common tissue of origin (mesenchyme derived from mesoderm) – Varying degrees of vascularity – Nonliving extracellular matrix, consisting of ground substance and fibers – Cells are not as abundant nor as tightly packed together as in epithelium Connective Tissue • Most diverse and abundant tissue • Main classes – – – – Connective tissue proper Cartilage Bone tissue Blood • Characteristics – Mesenchyme as their common tissue of origin (mesenchyme derived from mesoderm) – Varying degrees of vascularity – Nonliving extracellular matrix, consisting of ground substance and fibers – Cells are not as abundant nor as tightly packed together as in epithelium Connective Tissue: Embryonic Origin Figure 4.5 Functions of Connective Tissue • Enclose organs as a capsule and separate organs into layers. Areolar • Connect tissues to one another. Tendons and ligaments. • ?????. Bones. • Storage. Fat. • Insulation. Fat. • T???????. Blood. • P????????. Bone, cells of the immune system. Functions of Connective Tissue • Enclose organs as a capsule and separate organs into layers. Areolar • Connect tissues to one another. Tendons and ligaments. • Support and movement. Bones. • Storage. Fat. • Insulation. Fat. • Transport. Blood. • Protection. Bone, cells of the immune system. Structural Elements of Connective Tissue • Ground substance – unstructured material that fills the space between cells • Fibers – collagen, elastic, or reticular • Cells – fibroblasts, chondroblasts, osteoblasts, hematopoietic stem cells, and others Areolar Connective Tissue Figure 4.12b Adipose Tissue Figure 4.12c Reticular Connective Tissue Figure 4.12d Dense Irregular Connective Tissue Figure 4.12e Dense Regular Connective Tissue Figure 4.12f Elastic Connective Tissue • Bundles and sheets of collagenous and elastic fibers oriented in multiple directions • In walls of elastic arteries (aorta), lungs, vocal ligaments • Strong, yet elastic; allows for recoil of tissue after being stretched Hyaline Cartilage Figure 4.12g Elastic Cartilage Figure 4.12h Fibrocartilage Figure 4.12i Bone Tissue Figure 4.12j Blood Tissue Figure 4.12k Name this type of Tissue • Characteristics – Cells are referred to as fibers – Contracts or shortens with force when stimulated – Moves entire body and pumps blood • Types – Skeletal: attached to bones – Cardiac: of the heart. – Smooth: associated with tubular structures and with the skin. Nonstriated and involuntary. Muscle Tissue • Characteristics – Cells are referred to as fibers – Contracts or shortens with force when stimulated – Moves entire body and pumps blood • Types – S???????:attached to bones – C??????: muscle of the heart. – S?????: muscle associated with tubular structures and with the skin. Nonstriated and involuntary. Muscle Tissue • Characteristics – Cells are referred to as fibers – Contracts or shortens with force when stimulated – Moves entire body and pumps blood • Types – Skeletal:attached to bones – Cardiac: muscle of the heart. – Smooth: muscle associated with tubular structures and with the skin. Nonstriated and involuntary. Skeletal Muscle Tissue Figure 4.14a Cardiac Muscle Tissue Figure 4.14b Smooth Muscle Tissue Figure 4.14c Name this type of Tissue Figure 4.15 Nervous Tissue Figure 4.15 Tissues and Aging • Cells divide more slowly • Collagen fibers become more irregular in structure, though they may increase in number – Tendons and ligaments become less flexible and more fragile • Elastic fibers fragment, bind to calcium ions, and become less elastic – Arterial walls and elastic ligaments become less elastic • Changes in collagen and elastin result in – Atherosclerosis and reduced blood supply to tissues – Wrinkling of the skin – Increased tendency for bones to break • Rate of blood cell synthesis declines in the elderly • Injuries don’t heal as readily