fluid and electrolytes

Question 1

Which of the following directly caused Lauren’s weight gain?

increased sodium content of the blood plasma
increased absorption of water in the digestive system and an increased reabsorption of water by the collecting duct
increased secretion of Na+ at the collecting duct
decreased reabsorption of water by the collecting duct

Answer 1

increased absorption of water in the digestive system and an increased reabsorption of water by the collecting duct

Question 2

Which of the following statements best describes the condition (hyponatremia) that Lauren was diagnosed with?

There is a low sodium content in the urine.
There is a high sodium content in the extracellular fluid.
There is a high sodium content in the urine.
There is a low sodium content in the extracellular fluid.

Answer 2

There is a low sodium content in the extracellular fluid.

Question 3

What will happen to the osmotic pressure of the extracellular fluid in the body under a hyponatremia state and how could this affect the size and shape of your cells?

Osmotic pressure will decrease; cells will swell.
Osmotic pressure will decrease; cells will shrink.
Osmotic pressure will increase; cells will shrink.
Osmotic pressure will increase; cells will swell.

Answer 3

Osmotic pressure will decrease; cells will swell.

Question 4

Which of the following organ systems will be most negatively affected by the hyponatremic state?

brain
renal
heart
skeletal muscle

Answer 4

brain

Question 5

How would you expect aldosterone and vasopressin levels to change if a person had also run a race and had not taken in any water and produced a copious amount of sweat of 10 mEq/L

Vasopressin would increase while aldosterone would decrease.
Both vasopressin and aldosterone would decrease.
Both vasopressin and aldosterone would increase.
Vasopressin would decrease while aldosterone would increase.

Answer 5

Vasopressin would increase while aldosterone would decrease.

Question 6

Maintaining osmolarity is important to the body because the membranes of most cell types are freely permeable to ____.

cations
anions
proteins
water

Answer 6

water

Question 7

If a patient had damage to his posterior pituitary that resulted in decreased secretion of vasopressin, which of the following would you expect?

Increased urine output and increased blood volume
Decreased urine output and decreased blood volume
Decreased urine output and increased blood volume
Increased urine output and decreased blood volume

Answer 7

Increased urine output and decreased blood volume

Question 8

Most cell types are permeable to water. An exception is cells of the __________, which can be either impermeable or permeable, depending upon the location of __________.

loop of Henle; ion channels
distal nephron; aquaporins
distal nephron; ion channels
loop of Henle; aquaporins

Answer 8

distal nephron; aquaporins

Question 9

The __________ limb of the loop of Henle is permeable only to __________, which are reabsorbed all along the length because the fluid outside is __________ concentrated deeper in the medulla.

descending; water molecules; more
ascending; water molecules; less
descending; ions; less
ascending; water molecules; more

Answer 9

descending; water molecules; more

Question 10

Why is a high medullary interstitial osmolarity important to renal function?

It allows reabsorption of water.
It allows for fine-tuning of hormonal release from granular cells.
It allows solutes to leave the filtrate.
It allows retention of water in the urine.

Answer 10

It allows reabsorption of water.

Question 11

What is the mechanism of action of vasopressin?

Closure of V2 receptor channels, preventing sodium movement and osmosis of water from the tubule to the interstitial pace

Insertion of AQP2 into the apical membrane of collecting duct cells

Decreasing the resistance in the afferent arteriole

Opening of AQP2 channels in the basolateral surface of proximal tubule cells

Answer 11

Insertion of AQP2 into the apical membrane of collecting duct cells

Question 12

At a campus event, you ate a lot of salty treats. Why would osmoreceptors in the hypothalamus shrink, and what would you predict for vasopressin release?

Low plasma osmolarity, increased vasopressin release
High plasma osmolarity, decreased vasopressin release
Low plasma osmolarity, decreased vasopressin release
High plasma osmolarity, increased vasopressin release

Answer 12

High plasma osmolarity, increased vasopressin release

Question 13

What is the effect of countercurrent multiplier in the loop of Henle?

The filtrate becomes progressively more hyposmotic as it descends the loop.
Water is reabsorbed in the descending loop of Henle.
The filtrate is least concentrated at the deepest part of the loop of Henle.
Solutes (ions) are most concentrated as filtrate leaves the loop of Henle.

Answer 13

Water is reabsorbed in the descending loop of Henle.

Question 14

At a campus event, you ate a lot of salty treats. Which would you expect?

Aldosterone secretion and thirst
Vasopressin secretion and urination
Vasopressin secretion and thirst
Aldosterone secretion and vasopressin secretion

Answer 14

Vasopressin secretion and thirst

Question 15

What is the site and mechanism of the early response phase of aldosterone action?

Increased Na+/K+-ATPase activity in P cells of the distal nephron epithelium
Increased number of Na+ and K+ channels in on the basolateral membrane of collecting duct epithelium
Opening of aquaporins in the cortical collecting duct
Increased glucose secretion from the vasa recta

Answer 15

Increased Na+/K+-ATPase activity in P cells of the distal nephron epithelium

Question 16

Which of the following is the correct classification of vasopressin?

trophic hormone
neurohormone
classic hormone
neurotransmitter

Answer 16

neurohormone

Question 17

Which of the following structures is the site of release for vasopressin?

posterior pituitary
hypothalamus
anterior pituitary
adrenal gland
kidney

Answer 17

posterior pituitary

Question 18

Which of the following best describes the direct effect of vasopressin?

decreases blood plasma osmolarity
increases water reabsorption at the collecting duct of the kidney
increased blood plasma osmolarity
decreases water reabsorption at the collecting duct of the kidney

Answer 18

increases water reabsorption at the collecting duct of the kidney

Question 19

Sally goes to the emergency room (ER) seeking treatment for mild dehydration. The ER nurse mistakenly gives Sally an IV bag of solution that is very hypotonic to normal cells. Which of the following statements about the release of vasopressin reflects what would occur as a result of this mistake?

There is increased release of vasopressin.
There is decreased release of vasopressin.
There is not enough information to tell.
There is no effect on vasopressin release.

Answer 19

There is decreased release of vasopressin.

Question 20

Which of the following statements about aldosterone is NOT correct?

Aldosterone is stimulated by decreased plasma sodium levels and increased plasma potassium levels.
Aldosterone increases sodium reabsorption by increasing the number of Na+-K+ ATPase pumps in the luminal membrane of the proximal tubule.
Aldosterone increases the number of passive sodium channels in the luminal membrane of the distal tubule and collecting duct, thus aiding sodium reabsorption.
Aldosterone is produced in the adrenal cortex.

Answer 20

Aldosterone increases sodium reabsorption by increasing the number of Na+-K+ ATPase pumps in the luminal membrane of the proximal tubule.

Question 21

Which of the following statements about ADH (antidiuretic hormone) is correct?

ADH inserts water channels into the luminal membrane of the proximal tubules.
ADH is released by the posterior pituitary gland.
ADH is synthesized by the adrenal gland and works in the kidney.
ADH would increase urine volume.

Answer 21

ADH is released by the posterior pituitary gland.

Question 22

What is the osmolarity of the filtrate at the end of the proximal tubule?

isotonic – 300 mOsm
hypertonic – 600 mOsm
hypotonic – 100 mOsm
hypertonic – 1200 mOsm

Answer 22

isotonic – 300 mOsm

Question 23

In overhydration, what would be the levels of ADH (high, normal, or low) and what would be the osmolarity of the urine?

ADH – high; 600 mOsm (urine)
ADH – low; 600 mOsm (urine)
ADH – high; 100 mOsm (urine)
ADH – low; 100 mOsm (urine)

Answer 23

ADH – low; 100 mOsm (urine)

Question 24

In severe dehydration or blood loss, what would be the levels of ADH and what would be the urine flow rate?

ADH – low; low urine flow rate (0.25 ml/min)
ADH – high; low urine flow rate (0.25 ml/min)
ADH – low; high urine flow rate (16 ml/min)
ADH – high; high urine flow rate (16 ml/min)

Answer 24

ADH – high; low urine flow rate (0.25 ml/min)

Question 25

Aldosterone secretion increases in response to __________ and causes __________.

increased angiotensin II; sodium secretion
increased angiotensin II; sodium reabsorption
decreased angiotensin II; sodium secretion
renin; sodium reabsorption

Answer 25

increased angiotensin II; sodium reabsorption

Question 26

At a holiday celebration, you ate foods high in salt. Which would you predict?

Increased urine volume and increased blood volume
Decreased urine volume and decreased blood volume
Increased urine volume and decreased blood volume
Decreased urine volume and increased blood volume

Answer 26

Decreased urine volume and increased blood volume

Question 27

When aldosterone stimulates sodium reabsorption, why doesn’t water automatically follow?

There is no need for water to follow because reabsorbed sodium does not change ECF osmolarity.
The distal nephron epithelium is impermeable to water without vasopressin.
Aldosterone causes sodium reabsorption and water secretion.
Aldosterone causes sodium to be reabsorbed in the distal tubule, but all water reabsorption occurs in the proximal tubule.

Answer 27

The distal nephron epithelium is impermeable to water without vasopressin.

Question 28

Which of the following has a direct effect to signal for renin secretion?

Low blood pressure
Hypertension
High extracellular fluid volume
High plasma osmolarity

Answer 28

Low blood pressure

Question 29

Which hormone increases sodium excretion?

Atrial natriuretic peptide
Angiotensin II
Aldosterone
Renin

Answer 29

Atrial natriuretic peptide

Question 30

During a workout, a student drinks too much water. Which would you expect to be stimulated?

Angiotensin II
Oropharynx receptors
Salt appetite
The renin-angiotensin-aldosterone system

Answer 30

Salt appetite

Question 31

A patient has a tumor that secretes high levels of aldosterone. Which would you expect?

Hypokalemia and decreased potassium in urine
Hypokalemia and increased potassium in urine
Hyperkalemia and increased potassium in urine
Hyperkalemia and decreased potassium in urine

Answer 31

Hypokalemia and increased potassium in urine

Question 32

The ion imbalance known as __________ initially leads to __________ in excitable cells.

hypokalemia; depolarization
hyperkalemia; hyperpolarization
hypokalemia; repolarization
hyperkalemia; depolarization

Answer 32

hyperkalemia; depolarization

Question 33

During severe dehydration, the adrenal cortex receives two competing stimuli: high plasma osmolarity and decreased volume. In response to this, aldosterone is not released. Why is this helpful?

Aldosterone inhibits aquaporins. No aldosterone means that less water is lost in this pathway.
Aldosterone would increase sodium retention, leading to shrinkage of cells throughout the body.
Aldosterone would cause sodium secretion, causing osmosis and more water loss.
Aldosterone causes water loss that would add to the dehydration.

Answer 33

Aldosterone would increase sodium retention, leading to shrinkage of cells throughout the body.

Question 34

Dehydration leads to __________ blood volume, __________ blood pressure, and __________ osmolarity.

decreased; increased; decreased
decreased; decreased; increased
increased; decreased; increased
decreased; increased; increased

Answer 34

decreased; decreased; increased