Regulation of Sodium and Water Balance - McCormick

Question 1

How is plasma sodium regulated?

Answer 1

Primarily in changes in water balance

-same as osmolarity

Question 2

3 Factors that promote sodium reabsorption?

Answer 2

Renal sympathetic n
RAAS
Aldosterone

Question 3

3 Factors that promote Na excretion

Answer 3

ANP/BNP
Urodilatin
Prostaglandins

Question 4

What happens with increased renal sympathetic nerves?

Answer 4

Could be caused by fall in perfusion

1. Decreased GFR
2. Increased proximal Na and H2O
   - –these 2 lead to decreased fluid to MD
3. Direct stimulation of granular cells
   - -these 3 lead to increased renin secretion

Question 5

What are the effects of Ang II?

Answer 5

Systemic vasoconstriction
Efferent > afferent (decreased RBF) constriction
Na+ reabsorption
Thirst
ADH (post pit)
Aldosterone (adrenal cortex)

Question 6

What are aldosterones actions in late DCT/CD?

Answer 6

Stimulates Na reabsorption

Potassium and H secretion

Question 7

Factors controlling aldosterone secretion

Answer 7

Increased plasma K conc

Volume depletion

Question 8

ANP effects

Answer 8

Increased GFR - aA dilation and eA constriction
Suppresses renin, aldosterone, AVP
Systemic vasodilator

Question 9

There is an increased ECF volume, ANP response?

Answer 9

Increased ANP - this leads to increased medullary blood flow and GFR
Decreased Renin, Ang II, Na reabsorption

Question 10

Characteristics of urodilatin

Answer 10

Secreted by DCT/CD in response to increased arterial pressure and ECF volume
Suppresses Na and water reabsorption
NO systemic affect

Question 11

What do intrarenal prostaglandins do?

Answer 11

Increase Na excretion
Increase GFR (dilate arterioles)
Suppress Na reabsorption in TAL/CD

Question 12

What are the two major stimuli for ADH release?

Answer 12

Hyperosmolality
Volume depletion
-hypothalamic osmoreceptors > hepatic

Question 13

You are tired, you’ve been studying all day. You head home, turn on Netflix and open a bag of Ruffles. One season of the Girls Next Door and you are on your third bag of chips. What happens in the body?

Answer 13

Increased ECF
Increased ANP secretion
Decreased RAAS
Decreased NaCl reabsorption
Increased NaCl excretion in urine

Question 14

Hyponatremia

Answer 14

Too much water

Low plasma Na

Question 15

Hypernatremia

Answer 15

Too little water

High plasma Na

Question 16

Edema

Answer 16

Too much Na

Question 17

Volume depletion and Na content

Answer 17

Too little Na

Question 18

Student Doctor, Stew Bro, has decided to reenact the scene in Vampire Diaries where all of the people die. Josh, his fellow vampire aficionado, slips on a dirty sock and accidentally stabs Stu in the throat. As blood spurts everywhere, what happens to the activation of Ang II in Stew’s nearly lifeless ethnically ambiguous body?

Answer 18

Decreased arterial pressure
This leads to increased activity of renal symp nerves and RAAS
Ultimately leads to decreased excretion of sodium and water