Epithelial History Flashcards
What are the two membranes of the Epithelia?
The apical surface: facing the lumen.
The basolateral (basal) surface: Adjacent to underlying tissue (Next to the basement membrane)
Define microvilli.
Folds of the apical plasma membrane that increase membrane surface area.
Or
Acertain shape of the apical plasma membrane to increase the surface area for absorption of nutrients.
Define basement membrane.
Membrane that binds the epithelium to the underlying connective tissue. It consists of a thin layer of extra cellular proteins that is located next to the basolateral surface.
Define what a tight junction is and what it does.
Define epidermis.
The outer region of the skin. (1 of its 3 layers) (everything at yellow box and above yellow box is epidermis)
The epidermis is classified as what type of epithelium?
It is classified as a stratified squamous keratinized epithelium.
Stratified = the epithelium is many cells thick.
Squamous = cell flattened out at the apical surface.
Keratinized = Keratin (cellular protein) fills up cells and then cells die and keratin remains as a shield of sorts.
What are epithelia?
Where are they located?
Epithelia line hollow tubes and organs.
Epithelia are located at the boundary between the external environment and the internal environment
What are cells in the epidermis called?
Keratinocytes
Define the keratin layer.
As cells move apically, they become very flattened, and they fill up with an cellular protein, called keratin and die. For this reason, cells in epidermis are referred to as keratinocytes. This type of epithelium is protective, with the keratin layer acting to protect the underlying tissue from an abrasion and dehydration.
What type of epithelium line blood vessels?
Endothelium: Simple squamous epithelium.
Note: capillaries consist of just endothelium.
How do endothelial cells differ in the Central Nervous System?
Endothelial cells in the central nervous system are linked by tight junctions which help form the blood-brain barrier. Which is very tight compared to other epithelium, to restrict entry of substances.
(Between endothelial cells in brain capillaries)
What is the type of epithelium that you find in the small intestine?
Simple columnar epithelium.
Simple = single layer of cells.
Columnar = cells are tall and thin.
Define Enterocytes.
Columnar epithelial cells.
Define Enterocytes.
Columnar epithelial cells.
Define goblet cells.
Mucus-secreting cells in epithelium.
Define goblet cells.
Mucus-secreting cells in epithelium.
What type of epithelium is airway epithelium?
Pseudostratified ciliated epithelium.
Pseudo stratified = falsely stratified = is simple epithelium but looks like it’s stratified.
Ciliated = Cilia on surface of apical side.
Cilia vs Microvilli
Cilia contain motor proteins and actively beat.
Microvilli are folds of membrane that increase surface area.
