Anatomy Ch 4

• Epithelial
• Connective
• Muscular
• Nervous

• avascular - lacks own blood supply - nutrients and waste move via adjacent connective tissue
• epithelium - consists of cells arranged in continuous sheets (in single or multiple layers) - closely packed - little intercellular space
• covers body surfaces and lines hollow organs, body cavities, and ducts
• also forms glands

• bones and blood
• protects and supports body and organs
• binds organs together, stores energy reserves as fat, help provide immunity to disease-causing organisms

detects changes in a variety of conditions (inside and outside the body) - responds by generating action potential (nerve impulses) the help homeostasis

• first tissues formed in human embryo
• ectoderm - form epithelial and nervous tissue
• endoderm - form epithelial tissue
• mesoderm - form epithelial and connective tissue

move freely through body looking for invaders to destroy

group of similar cells that have a common embryonic origin and function together for a specific function

science that studies tissue

physician who specializes in lab studies of cells and tissue to help other physicians make accurate diagnoses

hollow area that is filled with something

generates the physical force needed to make body structures move

contact points between the plasma membranes of tissue cells

• 1. Tight Junction
• 2. adherens junction
• 3. desmosomes
• 4. hemidesmosomes
• 5. gap junctions

• weblike strands of transmembrane proteins - linkers
• fuse the outer surfaces of adjacent plasma membranes together
• close together - stuff not able to pass between cells
• 

• contains plaque - intracellular (space between cells) space exists - stuff can move between cells
• plaque - inside plasma membrane that attaches to membrane proteins & microfilaments
• cadherins - transmembrane glycoproteins that attach to plaque in adjacent cells and binds them
• adhesion belts - epithelial cells - extensive zones of adherens junctions
• 

• similar to adherens - involves plaque and cadherens - but does not attached to microfilaments
• Connects to intermediate filaments
• filaments extend across cell from desmosome to desmosome (spot-weld jucntions)
• very strong - give strength to cell and junctions - prevent cardiac muscle cells from pulling apart diring contraction
• 

• hemi = half
• resemble half a desmosome
• integrins - transmembrane glycoprotein used (not catherins as in desmosomes)
• attaches the cell to the basement membrane with laminin
• laminin - protein in the basement membrane that hemidesmosome is attached to
• 

• connexins - membrane protein that form tiny fluid-filled tunnels (connexons) that connect neighboring cells
• cells not fused - separated by intracellular space
• connects cytosol of neighboring cells - allow communication & transfer of nutrients and waste

• 1. apical surface - free surface - faces the body surface, a body cavity, the lumen of an internal organ, or tubular duct (may contain cilia or microvilli)
• 2. lateral surfaces - face adjacent cells on either side
• 3. basil surface - opposite surface of deepest layer adhere to basement membrane
• 4. basement membrane - supports epithelial and attaches to connective tissue
• a. basal lamina - closer to epithelial cells
• b. reticular lamina - closer to connective tissue - attached to connective tissue with fibroblasts
• 

• protection
• absorption
• secretion
• excretion

• 1. covering and lining epithelium
• 2. glandular epithelium

• classified by arrangement of cells into layers and shape of cells
• Cell Layers-
• 1. simple epithelium - singe layer of cells
• 2. pseudostratified epithelium - (false) appear to have multiple layers because nuclei lie at different levels
• 3. Stratified epithelium - two or more layers
• Cell Shapes
• 1. squamous cells - flat - allow for rapid passage of substances
• 2. cuboidal cells - relatively cube shape - function for secretion or absorption
• 3. columnar cells - taller than wide
• 4. transitional cells - change shape - bladder - expand to larger size and collapse to smaller size

• single layer of flat cells - nucleus is a flattened oval or sphere and it centrally located
• allows passage - sites where filtration (blood through kidneys) or diffusion (blood into oxygen)
• endothelium - simple squamous epithelial cells that line the heart, blood vessels, lymphatic vessels
• mesothelium - the epithelial layer or serous membranes (peritoneum)
• 

• secretions & absorption, ducts (tubules) lumen in the middle (unfilled area)
• relatively cube shape with round nucleus in the middle
• 

• secretion & absorption, ducts (tubules) - lumen in the middle (unfilled area)
• shaped like a column with a oval nucleus near the base
• nonciliated simple columnar - contains two type of cells - columnar epithelial cells with microvilli at their apical surface & goblet cells
• microvilli - fingerlike cytoplasmic projections - increase surface area
• goblet cells - modified columnar epithelial cells that secrete mucus
• ciliated simple columnar epithelial - contains columnar epithelial cells with cilia at the apical surface
• 

• pseudo = false...looks like more than one layer but all cells are attached to basement membrane
• 

• two or more layers of cells - more durable, can protect underlying tissue - some produce secreations
• cells in apical layer are flat - basal cells continually undergo cell division - as new cells grow the basal layer is pushed upward toward the apical layer. Cells at apical layer farther from blood supply - die and loose cell junctions - slought off
• 

• tough, fibrous protein - protects skin and underlying tissue
• keratinized stratified squamous epithelium - apical layer and several layers deep are paritally dehydrated and contain a layer of keratin - form superficial layer of skin
• nonkeratinized stratified squamous epithelium - lines mouth & espphagus - does not contain keratin and is moist

only present in urinary syste m - cells in apical layer look "puffy" (large and rounded) - able to stretched and return to original shape