4 Tissue Types
Epithelial- inner and outer surfaces Connective- connects parts of body together, encloses and protects organs Nervous- nerve cells and supporting (glial) Muscle- skeletal, cardiac, and smooth
Epithelial cells
line inner and outer surfacesex: skin, inner lining of blood vessels, lining of digestive tract"gate keeper" controls what goes in and out of layerTight junctions bind them together to keep things outPolarity: exposed to exterior (apical) and interior (basal) 4 Layers: (1 = simple, multiple = stratified) 3 shapes, pseudostratified= looks stratified but not, and transitional- simple as tissue stretches
Squamous Simple Epithelial Cell
found where materials cross a membraneflat with disk shaped nucleusallows passage of materials by diffusion where protection isn't importantex: kidney, air sacs of lungs, lining of heart, blood vessels and capillaries
Squamous Stratified Epithelial Cells
found where mechanical abrasion occurs protects underlying tissues in areas subject to abrasionkeratinized thick layers with an cuboidal or columnar baseex: lining of esophagus, mouth, epidermis of skin
Cuboidal Simple Epithelial Cells
single layer of cubelike cells with large nucleussecretion and absorptionex: kidney tubules, ovary, ducts
Columnar Simple
single layer of tall cells with round nuclei absorption, secretion of mucous, enzymessome contain cilia or mucous secreting (goblet cells)ex: non ciliated: gallbladder, excretory duct, ciliated: uterus, small bronchi
Pseudostratified Ephithelial Cells
single layer of cells with differing heights at different levelsfor secretion of mucous and ciliaex: male sperm ducts, trachea, respiratory tract
Transitional Ephithelial Cells
looks like stratified squamous and cuboidal, surface cellsdome shapedstretchy to permit distension of urinary organ by urinelines ureter, bladder, and urethra