A&P Chapter 5

Simple epithelium

One layer thick; all cells contact the basement membrane; functions in filtration, absorption, and secretion.

Stratified epithelium

Two or more layers; only basal layer touches basement membrane; found in areas of high mechanical stress.

Squamous cell shape

Flat, wide, irregular cells with flat nucleus.

Cuboidal cell shape

As tall as they are wide; spherical nucleus in center.

Columnar cell shape

Taller than wide; slender cells with oval nucleus in basal region.

Five general functions of epithelial tissue

Protection, barrier, reduce water loss, selectively permeable, secretion, absorption.

Basement membrane

Selective molecular layer that attaches epithelial tissue to underlying connective tissue.

Key characteristics of epithelial tissue

Closely packed cells, no extracellular matrix, polarity, avascular, innervated, high regeneration, basal layer divides.

Connective tissue definition

Most abundant tissue; supports, protects, binds structures; made of cells, protein fibers, and ground substance.

Ground substance

Molecular substance where CT cells and fibers reside; fluid, semisolid, or solid; supports, binds, cushions.

Extracellular matrix

Ground substance + protein fibers.

GAGs (glycosaminoglycans)

Large molecules; attract cations; water follows.

Skeletal muscle

Voluntary, striated, long cylindrical fibers, many nuclei, moves skeleton, thermoregulation.

Cardiac muscle

Involuntary, striated, short bifurcating cells, 1–2 nuclei, intercalated discs, pumps blood.

Smooth muscle

Involuntary, non-striated, spindle shaped, one nucleus, moves substances through organs.

Pseudostratified epithelium

Appears layered but all cells touch basement membrane; often ciliated with goblet cells.

Merocrine glands

Secretions released by exocytosis; cell lives; salivary and lacrimal glands.

Apocrine glands

Apical portion pinches off; mammary and ceruminous glands.

Holocrine glands

Entire cell ruptures; cell dies; sebaceous glands.

Mucous membrane

Lines cavities opening to exterior; absorbs, protects, secretes; lamina propria.

Serous membrane

Lines closed cavities; mesothelium; serous fluid reduces friction.

Cutaneous membrane

Skin; keratinized stratified squamous epithelium; prevents water loss.

Synovial membrane

Lines joints; areolar connective tissue; secretes synovial fluid.