Renal System, Renal Circulation

Question 1

Proximal tubular cellular structure.

Answer 1

Amplified apical membrane
– Invaginated baso-lateral membrane with numerous mitochondria

Question 2

Describe the cellular structure of the thin descending and thin ascending lips of the loop of Henle.

Answer 2

Poorly developed apical and baso-lateral surfaces
– Few mitochondria

Question 3

Describe the thick ascending limb and distal tubule of the nephron in the kidney.

Answer 3

Extensive infolding of the baso-lateral membrane
– Abundant mitochondria

Question 4

T/F. tightness of tubular epithelium increases from collecting ducts to proximal tubule.

Answer 4

F. increases from proximal tubule to collecting duct

Question 5

Describe cellular structure of principal and intercalated cells of late distal table and collecting duct.

Answer 5

– Principal cells
moderately invaginated baso- lateral membrane; few mitochondria

– Intercalated cells– high density of mitochondria

Question 6

Describe the cellular structure of the inner medullary collecting duct.

Answer 6

– Poorly developed surfaces
– Few mitochondria

Question 7

What the sympathetic neurotransmitters that act in the kidney?

Answer 7

NE and dopamine

Question 8

What are the ways in which sympathetic activation of the kidneys affects different components?

Answer 8

Smooth muscles of the renal blood vessels (α1 adreno-receptors) – vasoconstriction

Granular cells of the afferent arteriole – renin secretion

Renal tubule – ↑ Na+ reabsorption (directly from PCT via stimulating Na-H exchanger activity and indirectly with RAS stimulation)

Question 9

Where are the Renin and ATII producing granular cells located in the nephron?

Answer 9

afferent arterioles in Juxtaglomerular cells

Question 10

What is the function of the macula densa?

Answer 10

sensor of tubular fluid flow rate/deliver of NaCl

Question 11

Describe the Glomerular capillary bed.

Answer 11

• Is a high pressure bed (mean P ~ 60 mmHg) – is located between 2 arterioles (afferent and efferent)
• ultra-filtration of (180L/ day and more)

Question 12

Describe Peritubular capillary system.

Answer 12

• Is low-pressure bed (mean P ~ 13 mmHg)
• Is extremely porous
• Provides absorption of the ISF (180 L/day filtration rate; 1.5 L/day – excretion rate)

Question 13

What spinal cord levels is there sympathetic innervation of the kidneys?

Answer 13

T12-L2

Question 14

What spinal cord Level is there para-sympathetic innervation of the kidneys?

Answer 14

S2-S4

Question 15

In a condition of increased GFR, how will basal renal O2 consumption be affected?

Answer 15

will remain unchanged