L1: Intro to Renal Function

Question 1

How do you calculate balance?

Answer 1

Total input - total output

Input: food/beverage, oxidative water
Output: fecal, sweat, insensible

Question 2

If urine flow is = 110 ml/day, then the subject is in

Answer 2

steady state

Question 3

If urine flow is > 110 ml/day, then the subject is in

Answer 3

negative water balance (losing more than 1100 ml/day)

Question 4

If urine flow is < 110 ml/day, then the subject is in

Answer 4

positive water balance (losing less than 1100 ml/day)

Question 5

List 3 conditions that cause negative water balance

Answer 5

Diarrhea
Diuretic medications
Insufficient aldosterone (regulates Na to maintain BV)

Question 6

List 3 conditions that cause positive water balance

Answer 6

Excess steroids
CHF
Salt-retaining disease

Question 7

What is the osmolarity of the proximal tubule

Answer 7

Isosmotic

Question 8

Where are osmotic gradients generated in the nephron

Answer 8

Loop of henle (urine becomes concentrated)

Question 9

Where is the final concentration of urine adjusted in the nephron? How is water permeability controlled here?

Answer 9

Collecting duct

H20 perm. controlled by vasopressin (ADH)

Question 10

The ability to produce concentrated urine is proportional to _____

Answer 10

the number of juxtamedullary nephrons (deep medulla)

Question 11

Are nephrons in series or parallel

Answer 11

Parallel (collecting ducts shared by many nephrons)

Question 12

What are granular cells?

Answer 12

Surround afferent and efferent arterioles

Question 13

What are the 2 functions of the JGA?

Answer 13

1. Helps control GFR

2. Controls renin secretion (BP and volume)

Question 14

What cells contract in response to AGII?

Answer 14

Mesangial cells (between capillary loops)
AGII helps increase blood pressure (vasoconstrict)

Question 15

Are the two arteries and two capillary beds (glomerular and peritubular) in parallel or series?

Answer 15

Series

Question 16

Which nephrons have a vasa recta?

Answer 16

Juxtamedullary (think medulla)

Question 17

Vasa recta is important for the:

Answer 17

recovery of water

Question 18

What type of stimulation do the renal nerves receive (PNS or SNS)? What neurotransmitters are released and to what receptors

Answer 18

Sympathetic (NO parasympathetic innervation!)
Norepi and dopamine
Alpha 1 receptors

Question 19

What is the SNS effect on renal nerves? How is this opposed?

Answer 19

SNS: reduces RBF and GFR

Opposed by: Prostaglandins, PGE2 and PGI2, so reductions are minimized

Question 20

Granular cells are innervated by the SNS. What do they release upon stimulation of what kind of receptors?

Answer 20

B1 receptors stimulated —> Renin released