Epithelial Tissue Flashcards
Describe this Junction
This is a Adherens Junction.
The protein Cadherin spans the gap between adjacent cells.
The protein Catenin binds the Cadherin to the Actin of the Microfilament.
A key function is to prevent seperation by tension forces.
Describe this Junction
This is a Tight Junction.
It consists of a series of interwoven strands which bind the membrane of adjacent cells. Key proteins that make up the strands are Claudins and Occludins.
A key function is to maintain cell polarity by preventing migration of proteins between apical and basal surfaces.
Lots of these found in Stomach, intestines and bladder.
Name the 8 types of Epithelia
- Simple Squamous*
- Simple Cuboidal*
- Simple Columnar*
- Stratified Squamous
- Stratified Cuboidal*
- Stratified Columnar*
- Transitional
- Pseudostratified Columnar
The different types of epithelia arrangement
i. Simple: Single (Secretion; absorption; filtration)
ii. Stratified: 2+ layers - outer layer determines subtype (Protective)
iii. Pseudostratified - varying shapes/heights
The different shapes of epithelia
i. Squamous (Flat)
ii. Cuboidal
iii. Columnar
iv. Transitional
Simple Squamous Epithelium
Thin/flat single layer
Most delicate epithelium
Features:
1. Filtration of blood in the kidneys
2. Diffusion of oxygen into blood vessels of lungs
3. Secretion in serous membrane
What are the 2 specialised subtypes of Simple Squamous epithelium?
- Mesothelium
- Endothelium
Simple Cuboidal Epithelium
Single layer
Cuboidal
Features:
- Secretion (secreting portion of thyroid gland & pancreas)
- Absorption
Simple Columnar Epithelium
Single layer
Rectangular
Oval nuclei near base of cells
Scattered goblet cells
Contains more cytoplasm (so more organelles)
2 Specialised Subtypes (cilia or microvili)
Name the specialised subtypes of Simple Columnar Epithelium
- Ciliated
- Non-cilliated
Simple Columnar Epithelia: Ciliated
Single layer
Contain goblet cells
Function: synchronous movement assists mobility of mucus and forreign objects
Location: brochioles, uterine fallopian tubes, sinuses, central canal of spinal cord & ventricles of brain
Simple Columnar Epithelium: Non-Ciliated
Single layer
Microvilli on apical surface
Goblet cells
Non-motile projections: Increase surface area for absorption
Secretion, Lubrication & Absorption
Locations: lines gut, ducts of glands, gall bladder
