A&P Chapter 4 Histology

tissues

groups of cells similar in structure and function

four types of tissues

epithelial, connective, muscle, nerve

epithelial tissue

lines things and produce glands

cellularity

composed almost entirely of cells

polarity

apical and basal surfaces

special contacts

form continuous sheets held together by tight junction and desmosomes

basal layer

bottom layer ; connective tissue

apical layer

top layer which will probably be touching nothing

supported by connective tissue

reticular and basal laminae

avascular but innervated

contains no blood vessels but supplied by nerve fibers

regenerative

rapidly replaces lost cells by division

simple epithelial tissue

stratified epithelial tissue

squamous epithelial

cuboidal epithelia

columnar epithelial

simple squamous

single layer of flattened cells with disc-shaped nuclei and sparse cytoplasm

function of simple squamous epithelia

allows passage of materials by diffusion and filtration in sites where protection is not important ; lubricating substances in serosae

location of simple squamous epithelial

kidney glomeruli, lining of heart, blood vessels, lymphatic vessels, and serosae

simple cuboidal epithelial

single layer of cubelike cells with large, spherical central nuclei

simple cuboidal function

secretion and absorption

simple cuboidal location

kidney tubules ; ducts and secretory portion of small glands ; ovary surface

simple columnar epithelial

single layer of tall cells with round to oval nuclei; some cells bear cilia; layer may contain mucus-secreting unicellular glands (goblet cells)

simple columnar epithelial function

absorption; secretion of mucus, enzymes, and other substances; ciliated type propels mucus by ciliary action

simple columnar epithelium location

nonciliated type lines most of the digestive tract, gallbladder, and excretory ducts of some glands, ciliated variety lines small bronchi, uterine tubes, and some regions of the uterus

cilia

help move substance through internal passageways