A&P Chapter 4 - Lecture notes 5 PDF

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Biol 2401 with Prof. Vasefi...

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Anatomy & Physiology Chapter 4 CAMs: cell adhesion molecules Cell Junction: cells in tissue joined at plasma membrane by transmembrane proteins, 3 types  Tight junction: CAMs link plasma membranes of cells together by interlocking membrane protein o anchored to membranes of cytoskeleton, forming adhesion hooks o tissues relatively impermeable to fluids; prevents diffusion  Gap junction: plasma membrane of 2 adjacent cells not traveling o Made with transmembrane proteins (connexions), not CAMs; form tubes b/t cells o allows communication b/t cells (electrical impulses) o permit free diffusion of ions and small molecules  Desmosome: CAMs proteins link cells together o strong connection allows tissues to resist separation/tearing during movement o Hemidesmosome: specialized type of desmosome  links cells to basement membrane NOT to other cells  anchor to tissue & stabilizes shape o Spot Desmosomes  Small discs connected to the bands of intermediate filaments  Stabilize shape of the cell Apical Surface: faces body surface or internal body cavity Basal Surface: adheres to basement membrane Lateral Surface: (sides) faces adjacent cells Basement Membrane: produced by the basal surface and underlying connective tissue  basal lamina: secreted by overlying epithelial cells  reticular lamina: secreted by underlying connective tissue Tissue: group of cells & extracellular materials that work together to perform a function  structure & function depend on cell types/connection types b/t cells 4 Types of Tissue:  muscular, connective, nervous, epithelial Epithelial Tissue: covers body surfaces & lines body cavities  forms functional gland regions  exposed apical surface and an attached basal surfaces  cells arranged in continuous sheets and bound together by connections called cell junctions  avascular (lack blood vessels), supplied w/t nutrients by underlying connective tissue  many nerve endings, some specialize as sensory receptors Functions of Epithelial Tissue: form selective barriers to passages of substances in & out  form protective surface against external environment  EX: absorption of nutrients, waste secretion, hormone secretion, digestive juices, etc. Classification of Epithelium by Cell Shape:  squamous epithelium: cells flattened and irregular  cuboidal epithelium: cells cube/hexagon shaped  columnar epithelium: cells taller than wide  transitional epithelium: cells change shape as tissue stretches 3 Classification of Epithelium by # of Layers:  simple: 1 layer  stratified: multiple cell layers  pseudo-stratified: single cell layer but individual cells may not stretch from basal to apical

Glandular Epithelium: tissues within gland secrete substances  Two Types of Glands A. Exocrine Glands: have ducts  secrete products into ducts that empty to body surface/lumen/organ/tract (salivary gland)  Ex: products: mucus, sweat, digestive juices, enzymes  Three Modes of Secretion 1. merocrine: most EG are this, secrete products via secretory vesicles & exocytosis 2. apocrine: secrete products by pinching off apical cell surface, EX: mammary glands 3. holocrine: secrete products by rupturing cell, EX: sebaceous coil 1. Types of Secretion 1. Serous Glands  Secrete a watery solution that contains enzymes 2. Mucous Glands  Secrete mucin that hydrate to form mucous 3. Mixed Exocrine Glands  Contains more than one type of gland cell B. Endocrine Glands: ductless, secrete products into interstitial fluid of surrounding tissues  Gland Structure 1. Unicellular Glands- individual secretory cells 2. Multicellular Glands – glandular epithelia and aggregations of gland cells that produce exocrine and endocrine secretions Muscle Tissue: specialized for construction and producing movement A. Skeletal Muscle a. Long, cylindrical, striated and multimucleate b. Incapable of dividing c. Contains all four types of tissue B. Cardiac Muscle a. Found in the heart b. A typical cardiac cell, also known as a cardiocyte, is smaller than skeletal muscle c. Connected at specialized regions called intercalated discs C. Smooth Muscle a. Found in blood cells, and around hollow organs Neural Tissue: specialized for movement of electrical impulses from one region of the body to another 

Two basic types of cell 1. Neurons 2. Neuroglia

Inflammatory- inflammation isolates the injured area while damaged cells and area are cleared up Regeneration- repair process that restores normal function after inflammation has subsided

Connective Tissue: fills internal spaces; provides structural support for other tissues, transports material within the body, and stores energy  Basic Components: o Specialized Cells o Extracellular Protein Fibers o Fluid known as ground substances Classification of Connective Tissue: A. Connective Tissue Proper (Connective Tissue Fibers secreted by fibroblasts) 1. Collagen Fibers  Work in one direction  thick, straight, unbranched, strong & flexible, most abundant  fibers wound together like rope 2. Reticular Fibers  Force in many directions  Form a branching interwoven framework that is tough, yet flexible 3. Elastic Fibers  Can stretch by 150%  Branched and wavy  Returns to its original length o Lose Connective: loosely intertwined, fewer fibers, more cells a. Areolar Tissue  Least specialized  Forms a layer that separates the skin from deeper structure  Can distort without damage b. Adipose Tissue  Provides padding, absorbs shocks, & acts as an insulator  Known as “white fat” c. Reticular Tissue  Form a complex 3D stroma o Dense Connective: thicker, more protein fibers, fewer cells a. Regular  Collagen fibers are parallel to each other  Aligned with forces applied to the tissue b. Irregular  Fibers in an interwoven meshwork in no consistent pattern  Supports stresses from many directions B. Fluid Connective: blood and lymph cells C. Supporting Connective: cartilage and bone 1. Cartilage: dense network of collagen & elastic fibers in ground substance  Types a. Hyaline  Stiff but somewhat flexible support; reduces friction b. Elastic  Extremely resilient and flexible; structural support c. Fibrocartilage  Resists compression and prevents bone to bone contact  Growth a. Interstitial Growth: enlarges the cartilage from within b. Appositional Growth: adds new layers of cartilage to the surface

Connective Tissue Proper Cell Population:  Fibroblasts: only ells always present in connective tissue proper  Fibrocytes: spindle-shaped cells that maintain the connective tissue fibers  Adipocytes: fat cells Connective Tissue Ground Substance: polysaccharides & proteins  secreted by fibroblasts, fill space b/t cells & protein fibers  liquid (blood), semisolid & gelatinous (fat/cartilage) or calcified (mineral salts of bone) Lacunae- open spaces within extracellular matrix Tissue Membrane: flat sheets of tissues that cover/line body parts  Four Types: o Mucous membrane- line internal body cavities to communicate with the outside  forms barrier against pathogens (tight junction b/t epithelial cells)  secretes mucus which prevents desiccation & traps pathogens; reduces friction o

Serous membrane- lines internal body cavities  no opening to outside, little fluid filled sacs in which organs are suspended made of 2 layers: parietal layers attach to cavity wall, viscera layer attaches to organs  serous fluid secreted by epithelial cells  EX: pericardium (heart), pleura (covers lungs), & peritoneum Cutaneous membrane- skin: epidermal (superficial), dermis (deep) Synovial membrane- lines cavities of movable joints  secrete synovial fluid which lubricates joints, only has connective tissue 

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Peritoneum- covers various outside surfaces of organs in digestive system Tendons: Connect skeletal muscles to bones Ligaments: Connect one bone to another...