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Anat-Test-2

Anat-Test-2 - TISSUES 1 Tissues group of cells same...

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Unformatted text preview: TISSUES 1) Tissues- group of cells; same structure, intercellular substance, and function a) General Types- epithelial, connective, nervous, and muscular b) Epithelial Tissues i) General characteristics (1) Intercellular substance (a) Limited quantity densely packed (2) Basement membrane (a) Glycoproteins, proteoglycans, and collagen fibers (b) Come from epithelium and connective tissue below epithelium (3) Blood vessels- none in epithelial tissues (a) Nutrients and waste products must diffuse from/to b.v. in connective tissue (b) Diffusion- slow process (c) Epithelial tissue small b/c no blood supply (4) Nerve endings- almost none (a) Only in stratum basale layer of skin epidermis (5) High regenerative capacity (a) If damaged, repairs by mitosis (b) Lifespan (i) Epidermal (skin) cells- 28 days (ii) Intestinal epithelial cells- 5-7 days (c) Old, dying cells replaced by mitosis (6) Actual/Potential Free Surfaces (a) Actual- apical surface; no other tissue contacts it (i) Skin epidermis (ii) Inner lining of: GI tract, respiratory tract, excretory tract, and reproductive tract (iii) Closed body cavity surfaces: thoracic, abdominal, and pelvic (b) Potential- has potential to be actual (i) Inner lining of heart and b.v. (ii) Potential b/c in contact with blood (considered tissue) (iii) Actual free surface when no blood present (7) All glands derived from epithelia ii) Functions (1)Protection (a)Skin epidermis- protects underlying muscle (b)Respiratory epithelia (i) Contains goblet cells produce mucus (ii) Largely ciliated (2)Absorption- epithelial cells w/ microvilli (a) Small intestine- digested nutrients blood (b) Kidneys- tubule cells; absorb Na+, K+, H2O, glucose, amino acids filtered into forming urine (i) Microvilli reabsorb nutrients from urine return to blood (3)Filtration- endothelial cells of blood capillaries (a)Line heart and blood capillaries (i) 1 cell layer thick (b)Small molecules pass from blood to tissue spaces (c) Large molecules don’t filter (4)Secretion (a)Exocrine gland- secretes onto actual free surface (b)Endocrine gland- secretes into blood iii) Classification of Epithelia (1)# cell layers (a)1 cell layer- simple epithelium (b)2 or more- stratified epithelium (2)Shape of cells (a)Flat- squamous (b)Cubed- cuboidal (c) Taller than base- columnar (3)Cell shape of stratified= look at top layer iv) Specific Types (1)Simple squamous epithelium (a)Alveoli of lungs- “bubble like” (i) 1 cell layer thick; capillaries in walls O2 and CO2 exchange here (b)Walls of capillaries (endothelium) (c) Inner lining of closed body cavities (mesothelium): thoracic, abdominal, and pelvic (2) Simple cuboidal epithelium (a) Walls of kidney tubules (b) Lens of eye- outer layer (c) Secretory portion of thyroid gland (d) Lines ducts of exocrine glands (i) Ex- liver, pancreas, salivary glands...
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Anat-Test-2 - TISSUES 1 Tissues group of cells same...

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