ECM

Question 1

Define Epithelium

Answer 1

Sheets of cells covering the surface or lining a cavity
Responsible for the major function of most organs
Continuous sheets with junctions between cells
Rests on basement membrane
Avascular
Polarized

Question 2

What are the functions of the epithelial?

Answer 2

Depends on tissue function:
Barrier
Absorption and Secretion
Removal of substances
Gas exchange
Filtration

Question 3

What is the structure and function of Collagen I?

Answer 3

Fibril forming, multiple perpendicular layers

Provides structure and support

Question 4

What is the structure and function of Collagen IV?

Answer 4

Forms networks in the basal lamina
Breaks in the GlyXY chains allow flexibility, capped at the ends in order to form networks
Important in molecular filtration (e.g. glomerulus in kidney)

Question 5

What is the structure and function of Collagen VII?

Answer 5

Fibril like, remains capped at ends

Attaches the basal lamina to underlying connective tissue

Question 6

What is the mutation and presentation of Osteogenesis Imperfecta?

Answer 6

Mutation in Collagen I, Glycine is replaced with Serine, resulting in improper folding.
Manifests early on with fragile bones

Question 7

What is the mutation and presentation of Alport Syndrome?

Answer 7

Mutation in Collagen IV, Poor kidney function and also affects hearing and vision

Question 8

What is the mutation and presentation of Dystrophic Epidermolysis Bullosa?

Answer 8

Defect in Collagen VII, defect in anchoring fibrils to dermis

Question 9

What is Fibrillin?

Answer 9

Gives elasticity to tissues.

E.g. skin, lens of eyes, surface of bones

Question 10

What is Marfan Syndrome and what is its cause?

Answer 10

Symptoms include near-sightedness, myopia, elongation of limbs and fingers. Major complication is a defective aorta, aneurysms form and burst causing death.
Caused by a defect in Fibrillin 1