Epithelium Flashcards
Where are mucous membrane found
W/ examples
Found in the lining of body cavities exposed to the EXTERNAL environment
(E.g. Gut, Respiratory tract)
Where are serous membranes found
W/ examples
They line internal cavities
E.g. Peritoneum, Pericardial Sac, Pluera
What are the layers of mucous membranes
- Epithelial lining
- Connective tissue
- Smooth muscle
What are the layers of serous membranes
- Epithelial lining
- Connective tissue
What do mucous membranes secrete
Music which interacts with extra cellular H2O to form mucous
What do serous membranes secrete
Describe properties and function
Serous fluid
- It’s thin and watery and provides lubrication
Where does epithelium embryonically originate from
From all 3 germ layers (of trilaminar disc)
Name the 4 sub classifications of ‘Simple Epithelium’
- Simple Squamous
- Simple Cuboidal
- Simple Columnar
- Pseudostratified
State an example of where ‘Simple Squamous’ epithelia can be found
And
Relate it to its function
Bowman’s Capsule
Allows fast exchange of materials
Acts as a barrier to fluids
State an example of where ‘Simple Cuboidal’ epithelial can be found
And
Relate it to its function
Pancreatic Glands
- Secretion of substances
- Absorption of substances
- Barrier
Give an example of where ‘Simple Columnar’ epithelia can be found
And
Relate it to its fuction
In the GI lining (Crypts of Liberkühn)
- Absorption of material
- Secretion
- Lubrication
Where can ‘Pesudostratified’ Epithelia be found
And relate it to its function
The upper respiratory tract
- Mucous Secretion
- Particle trapping and removal
What is the function of microvilli
Increase surface area
Where can ‘Cilia’ be found and its relation to the ‘mucocillary escalator’
Found on the apical surface of pesudostratified cells in the upper respiratory tract
Mucous traps pathogens and the cilia beat to to move the mucous to be removed
Name the 5 sub-classifications of the ‘Compound/Stratified Epithelia’
- Simple Keratinised
- Simple Non-Keratinised
- Cuboidal
- Columnar
- Transitional
Where can Stratified Keratinised epithelial be found
And how does it relate to its function
Epidermis of skin
- Protection against abrasions
- Protection against water loss
- Shields against UV damage
How do stratified squamous epithelium turn into keratinocytes
They loose their nucleus and become ‘cornified’
Where can Simple Non-Keratinised epithelia be found
And
How does it relate to its function
The vagina
- Protection against abrasion
- Reduces water loss
Although it is rare, where can Stratified Cuboidal Epithelium be found
Sweat glands
- Secretion of materials
Although it is rare, where can Stratified Columnar Epithelia be found
In the male urthera
Where is the only place Transitional Epithelium be found
And
How does it relate to its function
Urinary passages (I.e Ureter, bladder)
- Able to distend
- Protection of underlying tissues from toxic chemicals
Explain how Cystic Fibrosis can cause thick secretions
- Goblet Cells secrete mucin to the surface of the cell
- Water is released onto the surface of cells and increased by release of ions
- CF decreases CHLORIDE IONS
- ⬇️ Cl ions -> ⬇️ H2O -> Thick mucous secretions
What genetic mutation causes the cystic fibrosis and thus over secretion of mucous
The CFTR Gene
Cystic Fibrosis Transmembrane Conductance Receptor
Where are club cells found
At the terminal bronchioles of the airways
What are the 3 main functions of club cells
1 - Detoxification of harmful substances
2 - Protection of epithelium
3 - Acts as stem cells
How do Club Cells protect the bronchiolar epithelium
By secreting uteroglobin
How do Club Cells detoxify harmful substances
By having Cytochrome P450 in their endoplasmic reticulum
Where are Microfold Cells ONLY found
In the small intestine
What are the 3 functions of Microfold cells
- Trap pathogens
- Present the pathogens to underlying dendritic cells
- Trigger am immune response by presenting to underlying lymphocytes and macrophages
What is the link between Microfold cells and infection
Can be used as a point of weakness in the intestinal wall for pathogens to enter
