Wall: Overview of renal structure and function

Question 1

what are the major cations of the ECFV and ICFV?

Answer 1

ECFV: sodium
ICFV: potassium

Question 2

What determines the size of total body water (TBW)?

Answer 2

total body sodium (TBNa)

Question 3

What is the major ECFV buffer?

Answer 3

bicarbonate

Question 4

What is the major contributor to blood pressure?

Answer 4

Na+

total body sodium content determines ECFV which determines BP/blood volume

Question 5

What are the major waste products eliminated by the kidney?

Answer 5

urea (from protein metabolism)
creatinine (from muscle metabolism)
uric acid (from nucleic acid breakdown)

Question 6

What are the main endocrine functions of the kidney?

Answer 6

EPO production
1-alpha hydroxylase (produces calcitriol)
renin production

Question 7

T or F: Bc the kidney regulates total body Na+ and therefore blood pressure, hypertensions is a kidney disease largely

Answer 7

T

Question 8

Catabolism of what key peptide hormone occurs in the kidney?

Answer 8

insulin

Question 9

What can happen with decreased nephron mass in terms of insulin catabolism?

Answer 9

slower degradation of insulin (increased half life)

Question 10

How many liters/day are formed at the glomerulus?

Answer 10

180

Question 11

what is an ultrafiltrate?

Answer 11

cell free, protein free filtrate of plasma that is iso-osmolar to plasma

the ultrafiltrate contains water and small solutes but not proteins or RBCs

Question 12

each kidney gets what percentage of the cardiac output?

Answer 12

10%

Question 13

How much filtrate is reabsorbed daily?

Answer 13

178 L/day (98-99% of the daily glomerular filtrate)

Question 14

How much urine is made daily?

Answer 14

1-2 L (180 of daily filtrate- 178 of reabsorbed filtrate)

Question 15

What is the best index of overall kidney function?

Answer 15

GFR

Question 16

What drives the filtrate formation at the glomerular capillaries?

Answer 16

Starling forces

Question 17

What are the 4 major processes involved in renal function?

Answer 17

filtration
reabsorption
secretion
excretion

Question 18

Kidneys are situated in the retroperitoneum from spinal levels ___ to ____

Answer 18

T12 to L3

Question 19

Renal cortex receives about ___% of total blood flow to the kidney

Answer 19

90%

Question 20

Where do all glomeruli reside?

Answer 20

renal cortex

Question 21

What is the vasa recta?

Answer 21

vessels from the juxtamedullary nephrons that follow the course of the loop of henle

Question 22

What does the renal hilum consist of?

Answer 22

renal artery and vein
renal pelvis
ureter
renal nerves
lymphatics

Question 23

What are the 3 sites of potential obstruction (via kidney stone) within the ureter?

Answer 23

1. pelvic ureteral junction
2. crossover of pelvic brim
3. urinary trigone

Question 24

Compare and contrast male and female urethra.

Answer 24

Male: longer, less UTI, goes through median lobe of prostate

Female: shorter, increase in UTI

Question 25

Where is the most common spot for obstruction in male urethra?

Answer 25

prostatic urethra (obstructive uropathy)

Question 26

What are the two types of nephrons?

Answer 26

cortical nephrons | juxtamedullary nephrons

Question 27

compare and contrast cortical and juxtamedullary nephrons.

Answer 27

cortical: 85% of nephrons, smaller, further from aorta, lower pressure inside glomerular capillaries (decreased filtration rate), short loop of henle, never at 100% capacity (reserve capacity) Juxtamedullary: 15% of nephrons, larger, closer to corticomedullary junction, higher glomerular pressure (higher filtration rate), longer loops of henle, always operate at full capacity

Question 28

What provides the only arterial blood supply to the medulla?

Answer 28

the desceding vasa recta (coming from efferent arterioles) that surround the loops of henle in the juxtamedullary nephrons

Question 29

the medulla is hypotonic/isotonic/hypertonic

Answer 29

hypertonic

Question 30

90% of blood goes to the cortex and only 10% to the medulla. Why is this crucial?

Answer 30

Bc the medulla is hypertonic. If a large amount of blood were to flow through the medulla, it would wash out the medullary solute and we could not make concentrated urine.

Question 31

How does the kidney maintain the medulla in a hypertonic fashion?

Answer 31

the vasa recta has countercurrent arrangement. Solute can be transferred between ascending and descending vasa recta