Regulation of Extracellular Sodium and Water

Question 1

The extracellular fluid is broken into two compartments: ____________.

Answer 1

the intravascular fluid and the interstitial fluid

Question 2

ECF volume is determined more by ___________. Why?

Answer 2

sodium content; because water moves to areas of higher sodium concentration–ingesting sodium pulls fluid from the intracellular compartment

Question 3

The content of sodium in the extracellular compartment is regulated by modulation of ________________.

Answer 3

renal reabsorption of sodium

Question 4

Methods of sodium and water regulation are _______ of one another.

Answer 4

indenpendent

Question 5

____________ receptors in the hypothalamus sense sodium.

Answer 5

Osmoreceptors

Question 6

Vasopressin is also called ____________.

Answer 6

anti-diuretic hormone

Question 7

ADH is synthesized in the ____________ and stored in the _________.

Answer 7

hypothalamus; pituitary

Question 8

Vasopressin levels increase in parallel with __________ levels; that is ___________.

Answer 8

urine osmolality; increased ADH increases resorption of water and hence increased concentration of urine

Question 9

ECF osmolarity is determined more by _________ than sodium balance.

Answer 9

water balance

Question 10

What is the primary effector protein for osmolarity?

Answer 10

ADH

Question 11

Ingestion of NaCl causes more of a change in ECF _______ than _________.

Answer 11

volume; osmolarity

Question 12

Sodium regulators determine regulatory activity by __________.

Answer 12

sensing changes in ECF volume

Question 13

When effective arterial blood volume (EABV) increases, sodium excretion __________.

Answer 13

increases

Question 14

What effector proteins are released in response to increased EABV?

Answer 14

Natriuretic peptides
Bradykinin
Dopamine
Prostaglandins

Question 15

Sympathetic nervous system activity promotes ____________.

Answer 15

sodium retention

Question 16

SNS input promotes ____________.

Answer 16

renin release, vasoconstriction, decreased RBF and GFR, and increased renal reabsorption of NaCl

Question 17

ANP causes dilation of the _________ arteriole and constricts the _________.

Answer 17

afferent ; efferent (and so increases GFR and increased sodium excretion)

Question 18

ECF water regulation is primarily an osmoregulatory system with an ________ override.

Answer 18

emergency low-volume

Question 19

List two things that induce vasopressin release.

Answer 19

Increased osmolarity (as detected on the hypothalamus) and decreased EABV (when EABV decreases by greater than 10%)

Question 20

What drug can stimulate release of ADH?

Answer 20

MDMA

Question 21

In terms of sodium and water balance, how will syndrome of inappropriate ADH (SIADH) present?

Answer 21

Hyponatremia with euvolemia

Question 22

IV saline stays in the _____________.

Answer 22

intravascular/ECF space

Question 23

The highest osmolarity of the inner medulla is ________.

Answer 23

1200 mOsm/L