Renal System and Diuretics

Question 1

What is the functional unit of the kidney?

Answer 1

Nephron

Question 2

What does the Glomerulus do?

Answer 2

Filters the blood that enters via the afferent arteriole

Question 3

What is the structure of the glomerulus?

Answer 3

1) Endothelia - Filters cells
2) Basement membrane - Has negative charge so repels proteins
3) Epithelial cells (podocytes) - Filters remaining proteins

Question 4

What drives filtration at the glomerulus?

Answer 4

Hydrostatic pressure

Question 5

What transporters are located in the proximal convoluted tubule?

Answer 5

Na+/H+ secondary transporter
Na+/K+ ATPase

Question 6

How does the Na+/H+ transporter gets its H+ ions?

Answer 6

Via the breakdown of carbonic acid by carbonic anhydrase

Question 7

What are the membranes that the transporters are located on?

Answer 7

Apical membrane - separates lumen and space
Basolateral membrane - separates space and peritubular capillaries

Question 8

What is the advantage of the Na+/K+ ATPase transporter?

Answer 8

Maintains concentration gradients

Question 9

What are the transporters present in the loop of henle?

Answer 9

Ascending loop of henle - NKCC2 transporter

Question 10

How does the NKCC2 transporter work?

Answer 10

1) Na+ down concentration gradient
2) Allows 2Cl- to go up its gradient - secondary couples transporter
3) K+ flows in and out to maintain membrane potential

Question 11

What transporters are located in the distal convoluted tubule?

Answer 11

NCC couples transporter on apical membrane - Na+/2Cl-

Question 12

Where does aldosterone and ADH act on?

Answer 12

Collecting duct

Question 13

What does aldosterone do?

Answer 13

Increases opening of Na+ channels
Increased Na+ being reabsorbed

Question 14

what does ADH do?

Answer 14

Increase permeability of distal tubule and collecting ducts to increase reabsorption,
Increases aquaporins

Question 15

What diuretics target the Proximal convoluted tubule?

Answer 15

Carbonic anhydrase inhibitors - Aromatic Sulphonamides

Question 16

What type of enzyme is carbonic anhydrase?

Answer 16

Metalloprotease - Zn2+

Question 17

What type of inhibitor is a sulphonamide?

Answer 17

COMPETITIVE - Competes with water against nitrogen on sulphonamide functional group.

Question 18

What part do thiazide diuretics target?

Answer 18

NCC transporters in distal convoluted tubule

Question 19

Summarise the key groups that a thiazide needs to be active

Answer 19

1) 2 sulphanilamide’s

Question 20

What factors enhance the activity of a thiazide med chem?

Answer 20

1) Electron withdrawing group next to sulphonamide group
2) Lipophilic group next to dihydropyridine group
3) Alkylation substitution of amine
4) Double bond saturation

Question 21

What amino acids bind with Zn2+ in carbonic anhydrase enzyme

Answer 21

3 Histidine

Question 22

Summarise the effect of diuretics and the role in hypertension

Answer 22

Decrease Na+ reabsorption by targeting transporters
Decreased water reabsorption
Decreased blood volume
Decreased peripheral resistance
Decreased blood pressure

Question 23

What stage of the NICE guidelines are thiazides introduced?

Answer 23

Stage 3

Question 24

Who should not be given thiazides and why?

Answer 24

People with Gout - blocks secretion of uric acid
Pregnant women
Renal and liver impairment

Question 25

Summarise the development of carbonic anhydrase inhibitors to thiazides

Answer 25

Sulphonamide derivative
Acylation = closed product ring = increased activity