T3 L10: Fluid balance

Question 1

What type of vasopressin receptor causes contraction of blood vessels?

Answer 1

V1

Question 2

Where are V2 receptors found?

Answer 2

In the basal membrane of principle cells in the collecting duct

Question 3

What type of Aquaporin is inserted into the collecting duct as a result of ADH activity?

Answer 3

AQP2

Question 4

What do maximal ADH levels do to urine output?

Answer 4

Minimise urine output

Question 5

What 2 factors cause ADH release?

Answer 5

Plasma osmolality and effective circulating volume (ECV)

Question 6

Which receptors detect changes in [Na+]?

Answer 6

Osmoreceptors in the hypothalamus

Question 7

Which receptors detect changes in pressure?

Answer 7

Baroreceptors

Question 8

Where is ADH released from?

Answer 8

The posterior lobe of the pituitary gland

Question 9

How does urea help to increase ECV?

Answer 9

It helps to reabsorb more water in the loop of Henle

Question 10

What is ECV?

Answer 10

Effective circulating volume. The volume of water in the body

Question 11

How do osmoreceptors help to decrease plasma osmolality?

Answer 11

They stimulate thirst and release of ADH so more water is reabsorbed in the kidneys and we increase the water intake

Question 12

How do baroreceptors help to increase ECV?

Answer 12

They stimulate the release of ADH, RAAS, ANP, and sympathetic NS

Question 13

Where are the 3 low pressure volume receptors in the body?

Answer 13

Large systemic veins, cardiac atria, and pulmonary vasculature

Question 14

Where are the 3 high pressure volume receptors in the body?

Answer 14

Carotid sinus, aortic arch, and the renal afferent arteriole

Question 15

What ion regulates ECV regulation?

Answer 15

[Na+]

Question 16

Where is decreased renal perfusion detected in the kideny?

Answer 16

In the afferent arteriole (the renal baroreceptor)

Question 17

Which cells in the kidney detect [Na+]?

Answer 17

Macula densa cells (renal Na+ sensor)

Question 18

What are the 5 effects of Angiotensin II?

Answer 18

1. Increases sympathetic activity
2. Increases tubular Na+, Cl-, and H2O reabsorption and K+ excretion
3. Stimulates aldosterone secretion
4. triggers arteriolar vascular contraction
5. Stimulates ADH secretion

Question 19

What are all the actions of Angiotensin II and aldosterone designed to increase?

Answer 19

ECV

Question 20

What does Aldosterone stimulate?

Answer 20

Na+ reabsorption in the distal tubule and collecting duct

Question 21

How does the RAAS react to a low ECV?

Answer 21

Low ECV is detected by renal baroreceptors and renal Na_ sensors. The RAAS is activated so Angiotensin II and Aldosterone work to reduce Na+ excretion and increase Na+ reabsorption in the kidneys

Question 22

How does the ANS react to low ECV?

Answer 22

Low ECV is detected by peripheral baroreceptors which signal to the hypothalamus. The ANS is activated causing direct effects on renal haemodynamic and the RAAS is activated. This causes reduced Na+ excretion and increased Na+ reabsorption

Question 23

How does ADH react to low EVC?

Answer 23

Low ECV is detected by peripheral baroreceptors which signal to the hypothalamus. ADH is released into circulation which causes increased reabsorption of water

Question 24

True or false, low ECV is the same as high plasma osmolality?

Answer 24

True

Question 25

What is ANP and what is its function?

Answer 25

Atrial natriuretic peptide and its designed to lower ECV by promoting natriuresis (Na+ excretion)

Question 26

Which molecule inhibits actions of renin and opposes effects fo Angiotensin II?

Answer 26

ANP

Question 27

Where is ANP produced and stored?

Answer 27

In atrial monocytes

Question 28

Which stimulates ANP release?

Answer 28

An increase in ECV causes atrial stretch which triggers release