Q: Which equation correctly represents the daily water balance in the human body, given the following values: water input from ingestion $$2.2\ \text{L/day}$$, water input from cellular metabolism $$0.3\ \text{L/day}$$, water output from feces $$0.1\ \text{L/day}$$, insensible loss and sweating $$0.9\ \text{L/day}$$, and urine $$1.5\ \text{L/day}$$?

$$2.2\ \text{L/day} + 0.3\ \text{L/day} = 2.5\ \text{L/day}$$; $$0.1\ \text{L/day} + 0.9\ \text{L/day} + 1.5\ \text{L/day} = 2.5\ \text{L/day}$$

Question 1

During intense exercise, sweating leads to a loss of water and electrolytes. Which of the following best describes the kidney's response to increased plasma osmolarity caused by sweating?

Accepted Answer

The kidneys increase water reabsorption, resulting in decreased urine output.

Question 2

Which equation correctly represents the daily water balance in the human body, given the following values: water input from ingestion $$2.2\ 	ext{L/day}$$, water input from cellular metabolism $$0.3\ 	ext{L/day}$$, water output from feces $$0.1\ 	ext{L/day}$$, insensible loss and sweating $$0.9\ 	ext{L/day}$$, and urine $$1.5\ 	ext{L/day}$$?

Accepted Answer

$$2.2\ 	ext{L/day} + 0.3\ 	ext{L/day} = 2.5\ 	ext{L/day}$$; $$0.1\ 	ext{L/day} + 0.9\ 	ext{L/day} + 1.5\ 	ext{L/day} = 2.5\ 	ext{L/day}$$

Question 3

Which of the following statements about sodium ($$	ext{Na}^+) $$reabsorption in the nephron is correct?

Accepted Answer

Sodium is actively transported out of the renal filtrate by Na+/K+ pumps at the basolateral membrane.

Question 4

A patient with hypernatremia (high plasma $$	ext{Na}^+) is $$likely to experience which of the following physiological changes?

Accepted Answer

Hypervolemia and increased plasma volume

Question 5

Which process is responsible for establishing the medullary osmotic gradient in the kidney, and what is its primary function?

Accepted Answer

Countercurrent multiplier; concentrates urine by increasing osmolarity in the medulla

Question 6

Which hormone increases water permeability in the late distal tubule and collecting duct by stimulating the insertion of aquaporin-2 channels?

Accepted Answer

Antidiuretic hormone (ADH)

Question 7

If the collecting duct is impermeable to water, what will be the characteristics of the urine produced?

Accepted Answer

High volume, low osmolarity

Question 8

Which of the following best describes the effect of aldosterone on sodium reabsorption in the nephron?

Accepted Answer

Aldosterone increases sodium reabsorption in the late distal tubule and collecting duct.

Question 9

Which of the following equations correctly represents the relationship between plasma osmolarity ($$O$$), total solute ($$S$$), and plasma volume ($$V$$)?

Accepted Answer

$$O = \frac{S}{V}$$

Question 10

Atrial natriuretic peptide (ANP) is released in response to increased plasma volume. What is the primary effect of ANP on the kidneys?

Accepted Answer

Decreased sodium reabsorption and increased sodium excretion

Question 11

Which of the following is NOT a direct effect of angiotensin II in the renin-angiotensin-aldosterone system (RAAS)?

Accepted Answer

Inhibition of sodium reabsorption in the nephron

Question 12

Which of the following scenarios would most likely trigger renin release from the juxtaglomerular cells of the kidney?

Accepted Answer

Decreased mean arterial pressure (MAP) and decreased blood volume

Question 13

Which of the following best explains why water is never secreted in the nephron?

Accepted Answer

Water is only filtered and reabsorbed because the nephron lacks mechanisms for water secretion.

Question 14

Which of the following is a consequence of decreased plasma osmolarity due to hyperhydration?

Accepted Answer

Neuron swelling and headaches

Question 15

Which of the following steps occurs first in the negative feedback regulation of ADH secretion in response to increased extracellular fluid osmolarity?

Accepted Answer

Osmoreceptors in the hypothalamus detect increased osmolarity

Question 16

Which of the following is the primary solute responsible for water reabsorption in the extracellular fluid (ECF)?

Accepted Answer

Sodium ($$	ext{Na}^+)$$

Question 17

Which of the following best describes the effect of ADH on aquaporin channels in the collecting duct?

Accepted Answer

ADH increases the insertion of aquaporin-2 channels in the apical membrane.

Question 18

Which of the following is a direct effect of increased plasma volume on the heart and kidneys?

Accepted Answer

Increased atrial wall stretch and increased ANP secretion

Question 19

Which of the following is a consequence of increased ADH secretion in response to decreased blood volume?

Accepted Answer

Increased water reabsorption in the kidneys and conservation of blood volume

Fluid and Electrolyte Balance: Water and Sodium Regulation

Study Guide - Practice Questions

Study Guide - Flashcards