Mangiarua - Hormonal Regulation Flashcards
What causes the release of renin from the granular cells in the juxtaglomerular apparatus ?
Decreased blood pressure,
Decreased extracellular volume
Decreased Na and Cl
Decreased Tubular fluid volume
Increased sympathetic stimulation
What is the end effect of renin ?
Increase blood pressure
Thru angiotensin -> aldosterone
Where is angiotensin converting enzyme located ?
In the lung
Half life of angiotensin II
1-3 minutes
How does sympathetic stimulation affect renin secretion?
Stimulates renin secretion by
Direct effect to beta-1 adrenergic receptors
Also decreased flow in macula densa
The major renal prostaglandin ?
PGE2
Where are kidney prostaglandins synthesized ?
Medullary and cortical collecting tubules (main location)
Glomerular and vascular endothelium
Renomedullary cells
What increases the synthesis of renal prostaglandins ?
Vasoconstrictors (angiotensin II, ADH, norepinephrine)
Prostaglandins are local vasodilators, so. They work to counter these
What does the infusion of PGE2 or I2 result in ?
Natriuresis and diuresis
Where is ADH formed ?
Supraoptic and paraventricular nuclei of the hypothalamus
ADH is rapidly metabolized by the liver and kidneys . What is its half life ?
15-20 minutes
What happens when ADH stimulates V2 receptors ?
V2 receptors *in principal cells). Cause an increase in water reabsorption
What happens when ADH stimulates V1 receptors.
There is a renal and systemic vasoconstriction
Disorder characterized by insatiable thirst and by excretion of large amounts of diluted urine as much as 25 L/day
Diabetes insipidus
Type of diabetes insipidus characterized by a decrease in the ability to concentrate urine due to a resistance to ADH action in kidney
Nephrogenic diabetes insipidus
Diabetes insipidus caused by decreased secretion of ADH
Central diabetes insipidusq
What can cause the release of aldosterone ?
Primary regulation; increased angiotensin II
Increased plasma potassium (this is very sensitive)
Increased level of ACTH
Aldosterone will be released in response to a(n) _________ in plasma potassium
Increase
Aldosterone increases Na and Cl reabsorption and increases K+ and H+ secretion by promoting protein synthesis for what transporters where?
Na aand K channels in the luminal side
Na-K-ATPase enzymes in the basolateral border
Explain aldosterone escape
Prolonged treatment w/ mineralcorticoids/aldosterone results in brief period of salt retention, that only lasts a few days
Effect on K excretion is sustained thru/o treatment period
Escape due to rise in ECF volume which effectively decreases Na reabsorption in proximal tubule
Half life of atrial natriuretic peptide?
2-4minutes
What causes the release of atrial natriuretic peptide ?
Hypervolemic states causing atrial stretch
What are the renal effects of atrial natriuretic peptide?
Inhibit Na reabsorption in the proximal tubule and cortical and medullary collecting ducts
Inhibit ADH dependent water reabsorption
Hyperfiltration - vasodilation of preglomerular arteries (increase GFR and FF)
Inhibit renin releases which decreases angiotensin II formation
What are the extrarenal effects of atrial natriuretic peptide ?
- Vasorelaxation
- Centrally stop the release of ADH (vasopressin)
- Inhibit aldosterone biosynthesis in the adrenal gland
Production of the active form of vitamin D is stimulated by release of parathyroid hormone due to a fall in calcium and by hypophosphatemia
What is the action of this mature vitamin D/
Increase intestinal absorption of Calcium and phosphate
Decrease release of PTH
Increase bone resorption
Increase calcium reabsorption in the kidney
