Water balance part 2

Question 1

True/False: Hormones can regulate water balance

Answer 1

True

Question 2

What is antidiuretic hormone (ADH)?

Answer 2

It is a small peptide molecule that is made in the hypothalamus and released by pituitary gland in the brain. ADH binds to receptor cells in the collecting ducts of the kidneys which promote the reabsorption of water into circulation instead of leaving in the urine. the urine osmolarity increases and the plasma osmolarity decreases. ADH promotes water reabsorption by stimulating the synthesis of Aquaporins. Reabsorption dilutes bodily fluids decreasing sodium concentration

Question 3

ADH stimulates the synthesis of what?

Answer 3

Aquaporins.
It also sorts aquaporins to the apical membrane of collecting ducts so water can pass through and get reabsorbed. Otherwise collecting ducts in kidneys are impermeable to water.

Question 4

ADH lowers osmolarity, what other mechanism does the kidney have to keep osmolarity from going too low?

Answer 4

Aldosterone

Question 5

What does Aldosterone do?

Answer 5

Aldosterone reabsorbs sodium (and water) in the kidney

Question 6

Where is the thirst center located?

Answer 6

the CNS

Question 7

Where is aldosterone released from?

Answer 7

adrenal cortex

Question 8

What happens if there is a decrease in arterial blood pressure? (hint angiotensin)

Answer 8

kidney receptors tell renin to increase. which tells angiotensinogen to increase in liver. which tells angiotensin I and II to increase. which increases Aldosterone, ADH, thirst. which intern increases Na+ reabsorption, water reabsorption, and fluid intake. arterial pressure returns to normal.

Question 9

how to regulate body fluid gain (when in dehyrdation)?

Answer 9

by adjusting preformed water intake (DRINK MORE WATER)

Question 10

What controls electrolyte balance?

Answer 10

HORMONES

Question 11

What three hormones regulate fluid loss?

Answer 11

1) Antidiuretic hormone (ADH)
2) Aldosterone
3) Atrial natriuretic peptide (ANP)

Question 12

What two factors stimulate the release of ADH?

Answer 12

1) Increased blood osmolarity

2) decrease in blood volume (same thing)

Question 13

What stimulates the release of Aldosterone

Answer 13

An increase in angiotensin II

Question 14

What is the opposite of ADH?

Answer 14

ANP

Question 15

When is ANP (atrial natriuretic peptide) released? In response to what?

Answer 15

When blood volume or blood pressure is increased, by the stretching of the walls of the atrium (heart), ANP is released to decrease it.

Question 16

What releases ANP (atrial natriuretic peptide)?

Answer 16

the cardiac muscle cells

Question 17

Does ANP increase or decrease urine flow?

Answer 17

ANP increases urine flow rate, which increases the excretion of water, which decreases the volume of water in the blood

Question 18

ADH and Aldosterone do what to urine flow rate?

Answer 18

ADH and Aldosterone decrease urine flow rate, which increases fluid absorption, and blood volume

Question 19

What cells monitor osmotic concentrations of the ECF?

Answer 19

osmoreceptors

Question 20

What cells are sensitive to subtle changes in osmolarity?

Answer 20

osmoreceptors

Question 21

Where are osmoreceptors located?

Answer 21

in the hypothalamus

Question 22

What are osmoreceptors?

Answer 22

are neurons in the anterior hypothalamus and their axons release ADH into the posterior pituitary gland

Question 23

What two effects does releasing ADH have?

Answer 23

1) it stimulates water conservation in the kidneys which reduces water loss, and concentrates the urine
2) it stimulates thirst to promote drinking of fluid

Question 24

what happens when there is a water deficit?

Answer 24

1) Plasma Osmolarity increases
2) activated Osmoreceptors release ADH from anterior hypothalamus into posterior pituitary gland
3) Thirst is stimulated
4) water permeability is increased in Collecting Ducts
5) Water is reabsorbed
6) plasma osmolality decreases to normal

Question 25

What determines the osmolality of the excreted urine?

Answer 25

The collecting ducts (because of its permeability of water)

Question 26

When is diluted urine produced?

Answer 26

when ADH is absent, the collecting ducts become impermeable to water (increasing urination and diluting the urine)

Question 27

When osmotic pressure of interstiital fluid goes down, ADH secretion stops. True or false

Answer 27

True

Question 28

During over-hydration what happens to interstitial osmotic pressure? ADH?

Answer 28

it decreases, it stops

Question 29

In normally functioning kidneys, what happens to the urine, and tonicity if ADH secretion STOPS.

Answer 29

If ADH secretion stops, excess water will be excreted into the urine, and hypotonicity will not occur

Question 30

If kidney function is poor (renal failure), what happens if ADH secretion STOPS

Answer 30

Excess urine will not be excreted:

1) water intoxication
2) Circulatory shock

Question 31

aldosterone release occurs in response to what?

Answer 31

the activation of the renin-angiotensin system not directly by sodium ion concentration

Question 32

what does the renin-angiotensin system do to blood volume and pressure

Answer 32

it increases blood volume and pressure

Question 33

what is erythropoietin?

Answer 33

it enhances red blood cell production

Question 34

What is the most abundant cation in the ICF

Answer 34

Potassium (K+)

Question 35

What does potassium play a key role in?

Answer 35

1) establishes resting membrane potential

2) establishes repolarization phase of action in nervous and muscle cells

Question 36

What hormone controls the plasma level of Potassium?

Answer 36

Aldosterone

Question 37

Which organ regulates K+?

Answer 37

kidneys

Question 38

How does ANP reduce blood pressure and volume? (4 things)

Answer 38

1) Increases water lose in the kidneys
2) Reducing thirst
3) Blocks the release of ADH
4) Stimulates vasodilation

Question 39

What opposes the actions of angiotensin II?

Answer 39

Atrial Natriuretic Peptide (ANP)