Control Systems and Drug Intervention Flashcards
When the macula densa detect more salt in the filtrate what is inhibited?
Renin
What does renin do?
Renin stimulates the conversion of angiotensinogen to angiotensin I which is then converted to angiotensin II by ACE (angiotensin coverting enzyme).
What does angiotensin II do?
- Increase sypathetic activity.
- Increase water and salt retention.
- Increase Aldosterone
- Increase vasoconstriction
- Increase vasopressin
All of which increase blood pressure.
What does aldosterone do to the kidney?
works on the distal convoluted tubule to make them permeable to sodium and water.
What is the function of Atrial Natruietic Peptide (ANP)?
It blocks angiotensin II at every level therefore causing sodium and water loss and lower blood pressure and vasodialation.
When is parathyroid hormone released?
When the parathyroid glands detect low Ca2+
What does PTH do to the kidney?
Increases the amount of Ca2+ channels that move calcium from the filtrate to the blood. Vitamin D is needed for this.
Also inhibits phosphate reuptake to prevent the formation of calcium phosphate
How do loop diuretics work?
They target the hypertonic zone of the renal medulla to make it less salty, this means that the loop of henle and distal tubule cannot resorb water as effectively.
How do thiazide diuretics work?
Target the salt resorbtion in the distal tubule and prevent it from working.
How do potassium sparing diuretics work?
stop sodium from being resorbed in the collecting duct so therefore stop the loss of potassium.
How does spironolactone work?
stops the effect of aldosterone on the kidney
How do carbonic anhydrase inhibitors work?
inhibit bicarb uptake in the PCT which makes the filtrate more osmotic which inhibits water uptake later on.
How do osmotic agents work?
stop the movement of water out of the filtrate, clinical use is contraversial. In diabetes mellitus the excess glucose in urine acts as an osmotic agent leading to excess water loss.
How do diuretics in general lower blood pressure?
Diuretics lower blood pressure not due to fluid loss but because the increase of salt in urine will decrease renin production which will lower blood pressure.
