Epithelial Transport

Question 1

Podocytes

Answer 1

cover the glomerular endothelium
slit membrane
minimal active transport
paracellular flux
permit free passage to water, salts, and small solutes but impede the passage of most the serum proteins

Question 2

Proximal tubule cells

Answer 2

leaky tight junctions
robust active transport
high water permeability
para and trans water flux

Question 3

Medullary Thick Ascending limb cells

Answer 3

very tight tight junctions
robust active transport
very low water permeability
no water flux

Question 4

Medullary collecting duct cells

Answer 4

very tight tight junctions
minimal active transport
variable water permeability
trans water flux

Question 5

ADH and AQ2 relationship

Answer 5

absence of (-)ADH signals renal collecting ducts: RETRIEVE AQP2
Lose water volume in urine (very diluted urine)

presence of (+)ADH signals renal collecting ducts: INSERT AQP2
Minimize water loss in urine (very conc. urine)