Renal Physiology Pt 4/4 "Others"

Question 1

Which is the most important stimulus for thirst?

Answer 1

Osmoreceptor input
(aka. osmoreceptor sensing high osmolarity in blood in hypothalamus)

Question 2

Diuretics site of action?
(i) Thiazides
(ii) Loop
(iii) K+-sparing

Answer 2

note: imp specific diuretics to rmb:

Loop - Furosemide!
K+-sparing - SEa TAn (see HF drugs for MOA)

Question 3

Hemodialysis vs Peritoneal dialysis process in one line?

Question 4

Cortical vs Medullary nephron:
(i) where is glom?
(ii) where is PCT and DCT?
(iii) where is loop of Henle?
(iv) major fxn?

Answer 4

Cortical vs Medullary nephron:
(i) where is glom?
- both in cortex
- but medullary nephron’s glom is nearer medulla

(ii) where is PCT and DCT?
- both in cortex

(iii) where is loop of Henle?
- medullary nephron’s deeper into medulla

(iv) major fxn?
Cortical nephron: excretion of waste products in urine

Medullary nephron: concentration of urine by counter-current mech

Question 5

1. recap: What is the normal GFR?
2. What is the GFR corresponding to the stage of kidney disease?
   (note: in stage 1, GFR can be normal/ lowered but doesn’t mean person no CKD - conversely, GFR is not only determine by kidney diseased states)
3. recall: factors affecting GFR?

Answer 5

• 180L/day
• GFR and Kidney Disease
  Stage 1 with normal or high GFR (GFR > 90 mL/min)
  Stage 2 Mild CKD (GFR = 60-89 mL/min)
  Stage 3A Moderate CKD (GFR = 45-59 mL/min)
  Stage 3B Moderate CKD (GFR = 30-44 mL/min)
  Stage 4 Severe CKD (GFR = 15-29 mL/min)
  Stage 5 End Stage CKD (GFR <15 mL/min)

(to mem: 90 -> 60 -> 45 -> 30 -> 15 – see notes for stages corr.)

3. NAPS:
   - net filtration p.a.
   - arteriolar tone
   - permeability of glom cap
   - surface area of glom