epithelial tissue

4 types of tissue & basic function

1) epithelial - covers body/lines organs & secretes

2) connective -structural frame work for body

3) nervous -conducts electrical impulses

4) muscle -contracts for movement

4 functions of epithelieum (p,f,a,d)

1) protection

2) filtration

3) absorption/secretion

4) diffusion

epithelium structure

1) Basal membrane-bottom

2) apical surface: exposed/open w/ cilia (move stuff) & microvilli (absorb via (+) surface area) on top

3) golgi apparatus- packaging & involved in secretion needed for skin purposes (ex: sweat or oil)

4) mitochondria- create energy for secretion of golgi

Apical is usually found in between where

lumen

Layers & shape of epithelium

• Layers

1) simple→ single layer

2) stratified→ multiple layers

3) pseudostratified→ often ciliated (hair like) and has an elongated shape/nucleus to make it seem more than one layer

• shape

1) squamous→ flat scale or 2d square

2) cuboidal→ cube-like

3) columnar→ cylinder like

Structure enables what…an example?

function

• ex: squamous in alveoli or vessel→ thinness of squamous used to allow diffusion

glandular epithelium (exocrine NOT endocrine) what does it secrete and have?

• mucin (makes mucus)

• have globulet cell

3 types of glands & their secretion

1. eccrine→secrete via endocytosis(secretory vesicles) (ex: sebum, enzymes)

2. apocrine→ shed aporical (top) cell to secrete

3. holocrine→cell WHOLE cell COMPLETELY destroys