Fluid balance

Question 1

What is diabetes insipidus

Answer 1

A condition whereby ADH is not working. Can be central- whereby its is not released by posterior pituitary or nephrogenic whereby the ADH receptors are not working properly

Question 2

What causes the release of ADH

Answer 2

Low volume detected by cardiopulmonary volume receptors

High osmolality detected by osmoreceptors in the supraoptic and paraventricular nuclei

Question 3

Describe SIADH

Answer 3

Whereby plasma levels of ADH are higher that normal for the persons plasma volume and osmolality. Patient retains water inappropriately.

Question 4

Factors that promote renin secretion

Answer 4

Decreased afferent arteriolar pressure
Increased sympathetic activity
Decreased macula dense NaCl delivery

Question 5

Where is renin released from

Answer 5

Juxtaglomerular cells

Question 6

What does angiotensin II do?

Answer 6

Increases thirst
Stimulates the adrenal gland to release renin
Increases constriction of the efferent arteriole
Promotes Na+ reabsorption through Na+ H+ exchangers

Question 7

What is the most powerful mediator of the release of aldosterone

Answer 7

High K+

Also angiotensin II

Question 8

What receptor does aldosterone bind to

Answer 8

Specific mineralcortocoid receptor

Question 9

What does binding of aldosterone to the mineralcotocoid receptor do?

Answer 9

Increases expression of Enac channels that cause Na+ reabsorption and thus water reabsorption. The Na+ that enters tubule cell leaves via Na+ K+ ATPase meaning you lose K+ from the blood.

Question 10

Hyperaldosteronism represents what percent of patients with essential hypertension

Answer 10

10%