Long Term Blood Pressure control

Question 1

How does the RAAS system work to increase BP?

Answer 1

1. Low BP means there is less water to be filtered through the kidney
2. Low glomerular hydrostatic pressure
3. Slower flow in the loop of henle
4. Increased time for NaCl reabsorption
5. Less NaCl makes it to the DCL
6. The macula densa senses low NaCl concentration/flow in the DCL
7. Juxtaglomerular cells increase their renin secretion
8. Angiotensin 2 increases efferent arteriole resistance, increasing the glomerular filtration pressure

Angiotensin 2 does many other things of course!

Question 2

Why is aldosterone a Hypokalemia risk?

Answer 2

Aldosterone increases sodium reabsorption and increases secretion of potassium and acid.

Effect:
Increase sodium
Decrease potassium
Decrease acidity

Question 3

What are the effects of angiotensin 2?

Answer 3

1. Increase sympathetic activity (more vasoconstriction)
2. Kidney:
   Increase sodium and chloride reabsorption
   Increase water reabsorption
   Increase potassium depletion
3. Adrenal gland:
   Increase aldosterone production
4. Posterior pituitary gland:
   Increase ADH release
5. Vasoconstriction of arterioles
6. Hypothalamus:
   Triggers thirst reflex

Question 4

Under which two disease circumstances does small artery remodelling occur?

Answer 4

Diabetes mellitus type 2 - impairs endothelium function but doesn’t change lumen size

Essential hypertension - retains endothelium function but decreases lumen size

Remodelling: increased wall thickness