Mangiarua - Hormonal Regulation

Question 1

What causes the release of renin from the granular cells in the juxtaglomerular apparatus ?

Answer 1

Decreased blood pressure,

Decreased extracellular volume

Decreased Na and Cl

Decreased Tubular fluid volume

Increased sympathetic stimulation

Question 2

What is the end effect of renin ?

Answer 2

Increase blood pressure

Thru angiotensin -> aldosterone

Question 3

Where is angiotensin converting enzyme located ?

Answer 3

In the lung

Question 4

Half life of angiotensin II

Answer 4

1-3 minutes

Question 5

How does sympathetic stimulation affect renin secretion?

Answer 5

Stimulates renin secretion by

Direct effect to beta-1 adrenergic receptors

Also decreased flow in macula densa

Question 6

The major renal prostaglandin ?

Answer 6

PGE2

Question 7

Where are kidney prostaglandins synthesized ?

Answer 7

Medullary and cortical collecting tubules (main location)

Glomerular and vascular endothelium

Renomedullary cells

Question 8

What increases the synthesis of renal prostaglandins ?

Answer 8

Vasoconstrictors (angiotensin II, ADH, norepinephrine)

Prostaglandins are local vasodilators, so. They work to counter these

Question 9

What does the infusion of PGE2 or I2 result in ?

Answer 9

Natriuresis and diuresis

Question 10

Where is ADH formed ?

Answer 10

Supraoptic and paraventricular nuclei of the hypothalamus

Question 11

ADH is rapidly metabolized by the liver and kidneys . What is its half life ?

Answer 11

15-20 minutes

Question 12

What happens when ADH stimulates V2 receptors ?

Answer 12

V2 receptors *in principal cells). Cause an increase in water reabsorption

Question 13

What happens when ADH stimulates V1 receptors.

Answer 13

There is a renal and systemic vasoconstriction

Question 14

Disorder characterized by insatiable thirst and by excretion of large amounts of diluted urine as much as 25 L/day

Answer 14

Diabetes insipidus

Question 15

Type of diabetes insipidus characterized by a decrease in the ability to concentrate urine due to a resistance to ADH action in kidney

Answer 15

Nephrogenic diabetes insipidus

Question 16

Diabetes insipidus caused by decreased secretion of ADH

Answer 16

Central diabetes insipidusq

Question 17

What can cause the release of aldosterone ?

Answer 17

Primary regulation; increased angiotensin II

Increased plasma potassium (this is very sensitive)

Increased level of ACTH

Question 18

Aldosterone will be released in response to a(n) _________ in plasma potassium

Answer 18

Increase

Question 19

Aldosterone increases Na and Cl reabsorption and increases K+ and H+ secretion by promoting protein synthesis for what transporters where?

Answer 19

Na aand K channels in the luminal side

Na-K-ATPase enzymes in the basolateral border

Question 20

Explain aldosterone escape

Answer 20

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

Question 21

Half life of atrial natriuretic peptide?

Answer 21

2-4minutes

Question 22

What causes the release of atrial natriuretic peptide ?

Answer 22

Hypervolemic states causing atrial stretch

Question 23

What are the renal effects of atrial natriuretic peptide?

Answer 23

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

Question 24

What are the extrarenal effects of atrial natriuretic peptide ?

Answer 24

1. Vasorelaxation
2. Centrally stop the release of ADH (vasopressin)
3. Inhibit aldosterone biosynthesis in the adrenal gland

Question 25

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/

Answer 25

Increase intestinal absorption of Calcium and phosphate

Decrease release of PTH

Increase bone resorption

Increase calcium reabsorption in the kidney