Epithelium Flashcards
What are the four classic tissues?
Epithelium
Connective Tissue
Muscle
Nerve
Where do you find epithelium?
- All internal and external skin surfaces
- The gut canal from inner lip to anal skin
- All glands associated with internal and external surfaces
- line all blood vessels
Where did epithelium arise from?
From all three germ layers:
ecto, meso and endoderm
What is an enterocyte?
Epthelia that lines the small intestine and is a absorptive cell.
What is the purpose of microvilli?
To increase the absorptive surface area.
What kind of junctions hold together epithelial cells?
Gap junctions
Tight junctions
Adherens
Desmosomes
Hemidesmosomes
Does epithelia have blood vessels?
No epithelia is avascular.
Why are epithelial cells capable of self renewal?
Because they contain stem cells in the basal lamina (basement membrane)
What is the name of epithelium that lines blood vessels?
It is called endothelium
What kind of cells that are within epithelium that produces mucus?
Goblet Cells
What are the five layers of the epidermis?
Cher: Stratum Corneum
Likes: Stratum Lucidum
Hot: Stratum Granulosum
Sex: Stratum Spinosum
Bam: Stratum Basale
In what layer of the epidermis do cells undergo apoptosis?
In the stratum granulosum
In what layer of the epidermis do the stem cells live?
In the stratum basale
Through what kind of junctions in the epithelia does intercellular communications occur?
Gap junctions
What junction connects intermediate filaments from one cell to the intermediate filaments of another?
Desmosomes
What junction connects the actin filaments from one epithelial cell to the actin filaments in another cell?
Adherens
What kind of junctions anchor epithelial cells to the basal membrane?
Hemidesmosomes
What are the three kinds of cytoskeleton in epithelium?
Microtubules
Actin Filaments
Intermediate Filaments
What kind of epithelial cytoskeleton is not part of cell junctions?
Microtubules
A cell without good intermediate filaments will?
Be weak and rupture when stretched.
***Remember that desmosomes and hemidesmosomes attach intermediate filaments in adjacent epthelial cells.
What disease is the result of failed desmoglein or mutations in cytokeratins?
Pemphigus (blistering disease)
What is the secretory pathway?
rER >> Golgi >> Vesicles >> Plasma Membrane
This occurs from the basal to apical layer.
What is the difference between merocine, apocrine and holocrine secretion?
Merocine: secretory vesicle fusion with plasma membrane.
Apocrine: secretion of vesicle with lipid droplet
Holocrine: Secretion that involves plasma membrane rupture
What are the three places we find stem cells in the skin?
Epidermal SC in stratum basale
Sebocyte SC in the sebaceous gland
Bulge stem cells in the hair follicle
