Anatomy I - Module 7 (Epithelial tissue)

Tissue

Group of specialized cells
Classified by structure, function, extracellular matrix

4 primary tissue

Epithelial
Connective
Muscle
Nervous

Epithelial tissue/Epithelium

Many cells packed together
Little to no extracellular matrix
Covers body surfaces and forms glands
Has basal, lateral, apical(free) sides
Capable of regeneration
Acts as barrier
Secretion of substances
Absorption of substances
Passing of substances
Avascular

Which sides do apical lateral and basal face

Apical - open space
Lateral - cells next to it
Basal - Bottom (Basement membrane)

Basement membrane

Extracellular structure (no cells)
Secreted by connective and epithelial tissue
Acts as glue to connect tissues
porous (Allows substances to move through)

Avascular

No direct blood supply

Microvilli

Increases surface area for absorption/secretion (Intestines)
Unable to move

Cilia

Moves material through (Trachea)
Able to move

Classification for number of layers of cells

Simple - One layer of cells, all in contact with basement membrane
Stratified - More than 1 layer, top layer determines classification
Pseudostratified - Appear stratified but simple, all cells contact basement membrane

Classification for shape of cell

Squamous - Flat
Cuboidal - Cube
Columnar - Taller than wide (Column)

Function of simple cells

Diffusion, Filtration, Secretion, Absorption

Stratified function

Protection

Pseudostratified function

Secretes and moves mucus

Squamous function

Allows diffusion and filter

Cuboidal/columnar function

Secretion and absorption
May include goblet cells

Goblet cells

Found in cuboidal/columnar/pseudo
Produces and secretes mucus

Keratinized/Nonkeratinized

K - Outer layer is dead cells
NK - Outer layer is alive cells

Transitional

Appears as columnar/cuboidal when unstretched, squamous when stretched

Simple squamous + examp

Diffusion/secretion/filtration
Blood vessels/Alveoli

Simple cuboidal

Secretion/absorption
Kidney tubules, glands + ducts

Simple columnar

Brush border, moves things
Uterine tube, intestine,

Pseudostratified columnar function + example

Synthesize and secrete music, absorption/protection
Upper respiratory tract

Stratified squamous

Cube at basement, flat as goes up
Nonkeratinized - Mouth, vagina, throat
Keratinized - Skin
Protects against abrasion

Transitional function

Protects against urine
Lining of urinary tract

Glands

Epithelial tissue adapted for secretion
2 types of glands: endocrine/exocrine

Endocrine

No ducts
No

Exocrine

Ducts
Secretes to exterior