Histology

the study of tissues

avascular

abscence of blood vessels

Exocrine

secretions are discharged onto the surface of the epithelium

Endocrine

hormones are realeased into the surrounding tissue and blood

Functions of Epithelia

- Provide physical protection

- Control permeability

- Provide sensation

- Produce specialized secretions

{CAMs} Cell adhesion molecules

transmembrane proteins

tight juncton

the lipid layers of adjacent cell membranes are tightly bound together by interlocking membrane proteins

gap junction

two cells are held together by embedded membrane proteins

desmosome

cell membranes of two membrane protiens are locked together by intracellular cement and by membrane proteins connected to a network of intermediate filaments

basement membrane

lies between the epithelium and underlying connective tissue

Simple Squamous

Location: Epithelia linign ventral body cavities; lining of heart and bloof vesslels; portions of kidney tubules; inner lining of cornea; alveoli of lungs  

Function: reduces friction;controls vessel permeability; performs absorption and secretion

Simple Cuboidal

Location: Glands; ducts; portions of kidny tubules; thyroid gland

Function: limited protection, secretion, absorption

Simple Columnar

Locations: Lining of stomach, intestines, gallbladder, uterine tubes, and collection ducts of kidneys

Function: Protection, secretion, absorption

Pseudostratified Ciliated Columnar

Location: Lining of nasal cavity, trachea, and bronchi; portions of male reporductive tract

Function:Protection, secretion

Transitional

Location: urinary bladder; renal pelvis of kidneys; ureters

Function: permits expansion and recoli after stretching