Anatomy Unit 2.3

Epithelial tissue (epithelium)

covers and protects surfaces, both inside and outside the body

Avascular

nutrients diffuse into the tissue (no vessels or direct blood supply)

Membranous epithelium

covers the body and some of its parts, lines serous cavities

Glandular epithelium

grouped in cords and forms glands (composed of epithelium and some connective tissue)

Basement membrane

connects epithelial tissues to its underlying connective tissues (made of glycoprotein)

Apical surface

free surface toward opening or lumen (faces the inside)

Lumen

opening of cavity, duct, or vessel

Lateral surface

where epithelial cells are attached to other epithelial cells

Basal surface

where the tissue is attached to the basement membrane

Simple epithelium

single layer of cells (allows movement of materials)

Stratified epithelium

more than one layer of cells (protection)

Pseudostratified epithelium

looks layered but is not

Squamous

flat or scale-like (allow for easy diffusion)

Cuboidal

cube-shaped or circular (contain more cytoplasm)

Columnar

taller than they are wide (secretion)

Smooth surfaces

reduce friction

Microvilli and cilia

increase surface area for absorption or secretion

Folded (transitional)

when it stretches, the folded regions can unfold to expand

Exocrine glands

glands with ducts (sweat, oil, milk, pancreatic juice)

Merocrine gland

fluid released through the cell membrane - does not damage the cell (salivary and sweat glands)

Apocrine gland

release portions of cells to release products (mammary and ceruminous glands)

Holocrine gland

release entire cells which rupture to release products, damages the entire cells (sebaceous glands)

Endocrine glands

No ducts - secrete directly into bloodstream

Hormones

products of the endocrine glands that are secreted into the bloodstream and carried throughout the body