RENAL 08: HORMONAL REGULATION OF BODY SALTS

Question 1

diuretics that block thick ascending limb of loop of henle lead to what effect on water?

Answer 1

Water wasting

Question 2

What are the conditions for Na balance?

Answer 2

Na intake must exactly equal Na excretion

Question 3

What is a positive sodium balance indicating

Answer 3

you have etra sodium retained in volume, so you epand ECF because body holds onto water (hyperosmotic), this expands the blood volume and increases arterial pressure as well as leads to an increase in body weight due to edema

Question 4

What is a negative sodium balance indicating

Answer 4

You have a decrease of sodium intake, and therefore a reduction in ECF (hyposmotic), so you have a volume contraction. Because blood volume is decreasing, this decreases arterial pressure and body weight

Question 5

What is ECV

Answer 5

Effective circulating volume; potion of ECF that is in the vascular system and effectively perfusing tisues

Question 6

Volume receptors on afferent side of circulation

Answer 6

Cardiac atria (will release ANP); intrathoracic veins

This is because of the relationship of salt and volume

Question 7

Afferent pressure sensors

Answer 7

Aortic and carotid baroreceptors (will communicate to brain if shit is going down); afferent arteriole also has an internal baroreceptor

Question 8

Afferent receptors in kidney specifically

Answer 8

Pressure sensors in macula densa will determine if you’ve got too much tubular fluid

Question 9

Efferent sensors - neurohumoral

Answer 9

RAAS
SNS/Catecholamines
ANP/BNP
Prostaglandins

Question 10

Efferent hemodynamic forces effect on kidney salt excretion

Answer 10

GFR effects, peritubular forces will either increase or decrease based on what is required

Question 11

Renal SnS activity leads to what?

Answer 11

Vasoconstrition of afferent arterioles - increased proximal tubule Na reabsorption.
Therefore-decrease GFR but what does go through you absorb more Na from.

Question 12

Tubuloglomerular feedback

Answer 12

Macula densa senses flow and salt content in lumen - this is going to feed back to glomerulus to tell it what to do. if flow and Na are high, this causes contraction of afferent arteriole to decrease GFR. If there is low flow and low salt, prostaglandins and NO will be released to increase filration in the glomerulus.

Question 13

Reinin is produced by what

Answer 13

Cells in the juxtaglomerular apparatus

Question 14

When is renin secreted?

Answer 14

In situations of low sodium

Question 15

If you have a high salt diet what does your renin secretion look like?

Answer 15

It’s low

Question 16

How do we control renin production (3)

Answer 16

1. SNS nerve activation (NE) - innervate afferent arterioles - activates b1 receptors and produce renin in juxtaglomerular cells
2. Low pressure on afferent arteriole - intrarenal baroreeptors within juxtaglomerular cells will sense this and produce renin so we hold onto more water
3. Macula densa - release of ATP causes reduced renin secretionof JG cells - prostaglaindins cause increased renin release from JG cells

Question 17

RAAS system

Answer 17

Renin –> Ang I –> ACE makes Ang II-

ANG II and ang III will stimulate aldosterone release from adrenal cortex (under ACTH presence), leaing to a dcrease of Na and H20 secretion. Ang II will also cause for ADH to be released from posterior pituitary

Question 18

ADH affects (salt/water)
Aldosterone affects (salt/water)

Answer 18

Water

salt

Question 19

What does aldosterone do

Answer 19

Affects late distalt ubule and collecting duct, inserts more NKA and also increases activity

Question 20

Is aldosterone potassium saving or wasting

Answer 20

wasting

Question 21

Is aldosterone sodium wasting or saving

Answer 21

Saving

Question 22

ANP is released from where

Answer 22

Atria (as well as ventricles but mostly atria)

Question 23

ANP is released when

Answer 23

when you have a volume overload and stretch is sensed

Question 24

What is the job of ANP

Answer 24

Salt wasting

Question 25

How does ANP affect the kidney

Answer 25

Affects vasculature similar to ang II , but also affects tubules. Unlike ang II however it has a dual effect:

1. DILATION of afferent arteriole (causes a net increase in GFR
2. Suppress renin, aldosterone, and decrese sodium reabsorption

Question 26

Other natriuretic proteins

Answer 26

BNP

Urodilatin

Question 27

What is a major cause of edema

Answer 27

increase in capillary hydrostatic pressure and decrease in oncotic pressure

Question 28

how do we treat edema

Answer 28

diuretics