Chapter 5Section 2 (part 2)

By: Hiba

WaleedAliRima

2nd hour

Epithelial Tissues Review● Function: to protect, secrete, absorb, and excrete.

● Differ in shape, size, and number cell layers.

● Lack blood vessels, divide readily, and are tightly

packed.

● They cover body surfaces, line the internal organ, and

compose glands.

Stratified Cuboidal Epithelium● 2 or 3 layers of cuboidal cells.

● Provide protection.

● Line the ducts of the mammary, sweat, and salivary

glands, and pancreas.

● Line some internal organs of reproductive system.

Stratified Columnar Epithelium● Several layers of cells.

● Usually top layer is columnar cells, and the layer closer

to the basement membrane are cuboidal.

● Found in male internal reproductive system, and part of

the pharynx.

Stratified Columnar Epithelium

Transitional Epithelium● Specialized to change in response to increased tension● Provides distensibility and protection● Forms the inner lining of urinary bladder, linings of

ureters, and part of the urethra● When walls contract, tissue is composed of many layers of

cuboidal cells but when they are distended (bloated), tissues stretch

● Acts as a barrier that prevents the contents of the urinary bladder to spread out into the internal environment

Glandular Epithelium● Function: secretion ● Found within columnar or cuboidal epithelium (one or

more compose a gland)● 2 Types of Glands:1. Exocrine Glands: secrete products that open onto

surfaces (on the skin)2. Endocrine Glands: secrete their products into tissue

fluid or blood

Glandular Epithelium cont.● Exocrine glands are classified according to the way they

secrete their products:1. Merocrine Glands: release fluid by exocytosis2. Apocrine Glands: lose small portions of their cell bodies

during secretion3. Holocrine Glands: release entire cells filled with secretory

products ● Either secrete mucus or serous fluid:

-Serous Fluid: watery and has a high concentration of enzymes

-Mucus: thick and rich in mucin (abundantly secreted by cells for protection)