Four Major Types of Tissue?

epithelial, connective, muscle & nerve

Epithelium Cellularity

~usually packed together forming continuous sheets of cells with little extracellular fluid

~bound together at many points by cell junctions such as desmosomes or tight juctions

Epithelium Polarity

Epithelium has two surfaces..

1) apical surface - exposed to either the exterior of the body or a cavity

2) basal surface - the deepest surface which rest on a basement membrane

Epithelium has

conncective tissue support..

~all epithelium rest on a membrane called basement membrane - 2 layers

1) basal lamina - primarily protein made by the cells.

2)  reticular lamina of connective tissue

Characteristics of the epithelium

~Avascular - it has no blood supply on its own, recieves nourishment from underlying tissue.

~has nerve supply

~regenerative

Locations of the Epithelium

~Body Coverings (surface of body)

~lines internal cavities

~Glandular epithelium - lines the secretion portion of glands

Functions of the Epithelium

~Protects the body (skin)

~Absorption (intestinal cells)

~Filtration (kindeys)

~Secretion (glands)