A&P 1

collections of specialized cells and cell products that perform a limited number of functions

four types of basic tissues:

type of tissue that covers exposed surfaces, lines internal passageways and chambers

type of tissue that fills internal spaces, provides structural support for other tissues, and stores energy reserves.

type of tissue which is specialized for contraction, includes skeletal muscles of the body, muscle of the heart and muscular walls of the hollow organs

type of tissue that carries information from one part of the body to another in the form of electrical impluses

structures that produce fluid secretions

several important factors of the epithelia:

avascularity

the presence of structural and functional differences between the exposed and attached surfaces

apical cells

basal cells

a complex structure produced by the basal surface of the epithelium and the underlying connective tissues

epithelial  cells that are damaged or lost at the exposed surface are continuously replaced through stem cell divisions

four functions of epithelial tissue:

-two plasma membranes are tightly bound together by interlocking membrane proteins

-prevent the passage of water and solutes between the cells

forms a narrow passageway that lets small molecules and ions pass from cell to cell

-CAMs and proteoglycans link the opposing plasma membranes

-very strong and can resist stretching and twisting (hold cells tightly together)

the 8 classifications of epithelium:

-one layer of flat cells
-most delicate
- protection, secretion, absorption, diffusion
-located in alveoli (lungs), lining of the heart and blood vessels

- cells form a series of layers
- generally located where mechanical stresses are severe
- surface of skin, lining of mouth, esophagus, anus