(04) - Glomerular Filtration

Question 1

(Separating Salt and Water)

• when you go south of the arcuate vessels the concentration in the interstitium progressively increases until it maxes out at the renal papilla

water and salt are separated as a result of hypertonicity

Question 2

(Key Factors in Developing the concentration gradient)

1-4. what are they

Answer 2

Question 3

unusual to have a membrane that isn’t impermeable to water

entire ascending limb - loop of henle - distal and connecting tubules - all impermeable to the movement of water

permeability in collecting ducts decided by aquaporin insertion (influenced by ADH)

Answer 3

becomes progressively more concentrated (happens because of segment where water can’t move - taking Na out through that entire area) - this allows genesis of concentration -

Question 4

(REnal Endocrine Functions)

1. primarily formed where?

Answer 4

1. in renal tubules and renal interstitial cells

Question 5

(Erythropoeitin)

1. a circulating glycoprotein produced where?
2. What monitor tissue oxygenation?
3. Release EPO with what? leads to what?

Answer 5

1. renal peritubular fibroblast-like type-1 intersitial cells
2. kidneys
3. tissue hypoxia; increased RBC prodution in bone marrow

Question 6

(Calcitriol)

1. most active form of what?
2. Formed in the what by what?
3. a hormone or a vitamin?
4. regulates what two things?

Answer 6

1. vitamin-D: 1,25-dihydroxycholecalciferol
2. proximal tubules by 1-alpha hydorxylation of 25-hydroxycholecalciferol (produced in liver)
3. a hormone
4. calcium and phosphate handling; cell growth

Question 7

(renin)

1. an enzyme secreted by what?
2. leads to activation of renin-angiotensin-aldosterone axis (systemic (BP)/local)
3. what two things does it regulate?

Answer 7

1. the kidneys (secreted in afferent arteriole) - when Na Cl retention in needed
2. extracellular volume and arterial blood pressure
   (pictured: systemic angiotenisin-aldosterone system)

angiotensin likes to vasoconstrict and is very potent at it! which elevates blood pressure - also causes release of aldosterone - acts on kidneys to increase exchange of Na and K in distal tubule - influences sodium balance - determine the systemic BP

Question 8

(Renal Innervation)

1. predominantly what type of fiber?

2-4. What are the three innervation sites (and what does each do)?

Answer 8

1. alpha-adrenergic sympathetic fibers
2. rental arterioles (preglomerular vasoconstrction)
3. Renal tubular epithelium (increased Na pump activity)
4. juxtaglomerular apparatus (renin secretion juxtaglomerular cells)

(these are sympathetic responses)

Question 9