Q: Which of the following equations correctly represents the relationship between plasma osmolality and sodium concentration?

$$Plasma\ osmolality = 2 \times [Na^+] + \frac{[Glucose]}{18} + \frac{[BUN]}{2.8}$$

Question 1

Which of the following best explains why athletes, such as tennis players, must continuously replace water and electrolytes lost during intense exercise?

Accepted Answer

To maintain circulatory homeostasis and proper muscle function

Question 2

Which body compartment contains the largest proportion of total body water?

Accepted Answer

Intracellular fluid

Question 3

A patient is experiencing cerebral swelling due to hypo-osmolarity. Which of the following best describes the movement of water in this scenario?

Accepted Answer

Water moves into the cells, causing them to swell

Question 4

Which hormone increases water reabsorption in the kidneys by inserting aquaporins into the collecting duct cell membrane?

Accepted Answer

Antidiuretic hormone (ADH)

Question 5

Which of the following equations correctly represents the relationship between plasma osmolality and sodium concentration?

Accepted Answer

$$Plasma\ osmolality = 2 	imes [Na^+] + \frac{[Glucose]}{18} + \frac{[BUN]}{2.8}$$

Question 6

Which of the following best describes the function of the sodium-potassium pump in maintaining fluid and electrolyte balance?

Accepted Answer

It uses ATP to actively transport $$Na^+$$ out of the cell and $$K^+$$ into the cell

Question 7

A person with excessive aldosterone secretion would most likely exhibit which of the following changes in electrolyte balance?

Accepted Answer

Increased $$Na^+$$ reabsorption and decreased $$K^+$$ reabsorption

Question 8

Which of the following is a major cation in the intracellular fluid (ICF)?

Accepted Answer

$$K^+$$

Question 9

During capillary exchange, what causes net filtration at the arterial end of a capillary?

Accepted Answer

Capillary hydrostatic pressure is greater than blood colloid osmotic pressure

Question 10

Which of the following best describes the effect of parathyroid hormone (PTH) on blood calcium and phosphate levels?

Accepted Answer

PTH increases blood calcium and decreases blood phosphate

Question 11

A patient is given a medication that blocks the action of antidiuretic hormone (ADH). What is the most likely effect on urine output and plasma osmolality?

Accepted Answer

Urine output increases, plasma osmolality increases

Question 12

Which of the following is a non-electrolyte found in body fluids?

Accepted Answer

Glucose

Question 13

Which hormone is released in response to increased blood volume and acts to decrease sodium reabsorption in the kidneys?

Accepted Answer

Atrial natriuretic peptide (ANP)

Question 14

Which of the following best describes the movement of potassium ($$K^+) in $$relation to sodium ($$Na^+) $$during electrolyte regulation?

Accepted Answer

$$K^+$$ moves in the opposite direction of $$Na^+$$

Question 15

Which of the following mechanisms is responsible for the majority of water reabsorption in the kidneys?

Accepted Answer

Osmosis through aquaporins

Question 16

A patient with chronic kidney disease is unable to excrete phosphate efficiently. What is the expected effect on blood calcium levels, assuming parathyroid hormone (PTH) is functioning normally?

Accepted Answer

Blood calcium levels will decrease due to increased phosphate binding

Question 17

Which of the following best describes the effect of ANP (atrial natriuretic peptide) on blood pressure?

Accepted Answer

ANP decreases blood pressure by increasing sodium excretion

Question 18

Which of the following is the primary mechanism for glucose transport across the cell membrane?

Accepted Answer

Facilitated diffusion via carrier proteins

Question 19

Which of the following best explains why the brain is particularly sensitive to changes in plasma osmolality?

Accepted Answer

Rapid shifts in water can cause cerebral swelling or shrinkage

Question 20

Which of the following best describes the effect of calcitonin on blood calcium and phosphate levels?

Accepted Answer

Calcitonin decreases blood calcium and increases blood phosphate

Fluid and Electrolyte Balance: Structure, Function, and Regulation

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