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33 Cards in this Set

  • Front
  • Back
Where is ADH secreted from?
Posterior Pituitary
What are the two functions of ADH?
Increase peripheral vascular resistance and control reabsorption of molecules in the tubules of the kidneys.
Where does ADH increase water absorption?
Distal tubule & Collecting Duct
How does ADH increase water absorption?
Insertion of Aquaporin-2 into the apical membrane of the distal tubule
On what receptors does ADH act?
V2 - G protein-coupled receptors
How does the insertion of Aquaporins by ADH occur?
V2 receptors couple to Gs activating adenylyl cyclase, rise in cAMP triggers insertion.
Other than insertion of aquaporins what other role does ADH play in the kidney?
Increases permeability of inner medullary portion of collecting duct to urea allowing increase reabsorption of urea into the medullary interstitium.
What effect does ADH have on the cardiovascular system?
Increases peripheral vascular resistance and thus increases arterial blood pressure.
When is ADH mediated increase in vascular resistance imporant?
As a compensatory mechanism in hypovolemic shock eg during hemorrhage
ADH is secreted from posterior pituitary in response to what three things?
Reduction in plasma volume
Response to increase in plasma osmilality
Response to cholecystokinin from small intestine
How is ADH secretion in response to reduced plasma volume mediated?
Activated by baroreceptors (Carotid Sinus, Aortic Arch and low pressure receptors in veins, pulmonary vessels
How is ADH secretion in response to increased plasma omsotic pressure mediated?
Osmoreceptors in the hypothalamus
What are the symptoms of decreased ADH release or decreased sensitivity to ADH?
Diabetes insipidus -> hypernatremia, polyurua, polydipsia
Where is angiotensinogen produced and released?
The liver
Where is renin produced?
Kidneys - Granular cells of juxtaglomerular apparatus
Name three stimuli increasing renin production in the kidney? Which cells detect these changes?
Decrease in arterial blood pressure detected by baroreceptors.
Decrease in sodium chloride levels in ultra-filtrate of nephron measured by macula densa of juxtaglomerular apparatus.
Sympathetic nervous system activity through beta1 adrenergic receptors
What exactly does renin do?
Cleaves the peptide bond between leucine and valine residues on angiotensinogen creating angiotensin I/
What biological activity does angiotensin I have?
None, solely exists as precursor to angiotensin II.
What enzyme converts angiotensin I to angiotensin II?
Angiotensin-converting enzyme
Where is angiotensin converting enzyme found?
Predominantly in capillaries of the lung
What does angiotensin II do overall?
Increase blood pressure and blood volume.
Name five specific effects of angiotensin II?
1. Increase sympathetic activity
2. Increase secretion of aldostrone
3. Increase tubular Na+, Cl- reabsorption and K+ excretion causing water retention
4. Arteriolar vasoconstriction
5. Increased ADH secretion from posterior pituirary
What does aldosterone do?
Increases reabsporption of sodium ions and water and release of potassium in the distal convoluted tubules.
Where is aldosterone produced?
Zona glomerulosa of adrenal cortex
Where does aldosterone act?
Distal tubules of nephron
In what condition is aldosterone activity reduced?
Addisons disease
In what condition is aldosterone activity increased?
Conn syndrome
Name three factors stimulating aldosterone release:
Plasma acidosis
Stretch receptors in atria of heart
Increase in plasma angiotensin II
Name a renin inhibitor?
What is its mode of action?
Aliskiren
It binds to the S3bp binding pocklet of renin which is essential to its activity
Name an ACE inhibitor?
Captopril, Benazepril, Ramipril
Name an Angiotensin receptor antagonist?
Valsartan, Losartan, Candesartan
Name an aldosterone antagonest?
Spiranolactone
What does spironolactone do?
Aldosterone Antagonist/Potassium sparing diuretic
Causes sodium and water loss