Tissues - Epithelial Cells

Tight Junctions

• located near the apical surface

• Form a seal between cells by forming their plasma membranes

• Prevent substances from passing between from passing between epithelial cells

• Makes them move through cells instead of between them

• Each rivet is a transmembrane protein

Adhering junctions

• located below tight junctions

• Prevent lateral surfaces from separating and allowing space for substances to enter

• Wrap around the cell

• Contain plaques and micro filaments line the plaques, together they make adhesion belts

Desmosomes

• consists of dislike proteins called plaques held together and spaced apart by linker proteins

• Function as structural reinforcements at specific stress points

• Contain intermediate filaments that connect desmosomes to other desmosomes

Gap Junctions

• allow small substances to be transported between adjacent cells

• Each gap contains a small group of tubular structures which are composed of a cluster of six proteins called connexins and has a fluid filled channel running down the center

Simple squamous epithelium endothelium

Lines blood vessels, lymph vessels, and chamber of the heart

Simple squamous epithelium mesothelium

Lines serous cavities

• pleural

• Pericardial

• Peritoneal

Keratinized stratified squamous epithelium

Contains keratin

Stronger

Made from intermediate filaments

All dead at the surface, no nuclei, no dna

Non keratinized stratified squamous epithelium

Mouth, vagina, anus

Some living cells at the surface