Human Anatomy and Physiology 4.1 & 4.2, Types of Tissues and Epithelial Tissue

Epithelial tissue

Covers body surfaces; lines body cavities, hollow organs and ducts, forms glands

Connective tissue

supports the body’s organs and binds them together, stores energy as fat, and provides immunity

Muscular tissue

Generates the physical force needed to make body structures move

Nervous tissue

Detects changes inside and outside the body and sends nerve impulses to help maintain homeostasis

Cell junctions

Specialized structures that connect cells to each other and the extracellular matrix

Covering and lining epithelium

Tissue forms the outer covering of the skin and some organs

Glandular epithelium

Makes up the secretion portion of the cells, like sweat glands

Apical surface

Top surface of the epithelial cells that face the lumen of an organ or external enviornment

Lateral surfaces

face adjacent cells of either side

Basal surface

Attached to a basement membrane

Basement membrane

A thin extracellular structure composed mostly of protein fibers

Are epithelial tissues avascular?

Yes

Avascular

Lack of blood vessels

Simple epitheliam

A single layer of cells that function in diffusion, osmosis, filtration, secretion, and absorption

Secretion

The production and release of substances

Absorption

The intake of fluids or other substances

Pseudostratified epithelium

Appears to have multiple layers of cells but doesn’t

Stratified epithelium

Consists of two or more layers of cells, protects places prone to wear and tear

Squamous cells

Thin and fit together like puzzle pieces

Cuboidal cells

Tall and wide, shaped like cubes or hexagons

Columnar cells

Much taller than they are wide, shaped like a column

Transitional cells

Cells that can change shape, mainly to stretch and shrink

Ciliated

Meaning that the cells have cilia, tiny hair-like proteins on the outside of some cells

Types of Epithelia

Simple epithelium and stratified epithelium

Simple epithelium includes

Simple squamous epithelium, simple cuboidal epithelium, simple columnar epithelium, and pseudostratified columnar epithelium

Stratified epithelium includes

Stratified squamous epithelium, stratified cuboidal epithelium, stratified columnar epithelium, and transitional epithelium

Endocrine glands

Secretion enters the interstitial fluid, then diffuses into the bloodstream without flowing through a duct

Exocrine glands

Secretes their products into ducts that empty at the surface of the covering and lining epithelium