Q: A patient receives an intravenous solution of 0.9% NaCl. Why is this solution considered isotonic to blood?

Because its osmolarity is approximately $300\ \text{mOsm/L}$, matching that of blood plasma.

Q: Which equation best represents the calculation of osmolarity for a solution containing $150\ \text{mM}$ NaCl?

$\text{Osmolarity} = 150\ \text{mM} \times 2 = 300\ \text{mOsm/L}$

Question 1

Which of the following best describes the difference between diffusion and osmosis across a cell membrane?

Accepted Answer

Diffusion is the movement of solute and solvent down their concentration gradients, while osmosis is specifically the movement of water across a semi-permeable membrane.

Question 2

A patient receives an intravenous solution of 0.9% NaCl. Why is this solution considered isotonic to blood?

Accepted Answer

Because its osmolarity is approximately $300\ 	ext{mOsm/L}$, matching that of blood plasma.

Question 3

Which of the following is the primary extracellular cation in human physiology?

Accepted Answer

Sodium ($Na^+$)

Question 4

If a cell is placed in a solution with $150\ 	ext{mM}$ NaCl, what will happen to the cell?

Accepted Answer

The cell will remain the same size because the solution is isotonic.

Question 5

Which membrane transport mechanism requires energy in the form of ATP?

Accepted Answer

Active transport

Question 6

A patient with renal failure is unable to regulate electrolyte balance. Which concept best explains why hemodialysis can help restore homeostasis?

Accepted Answer

Hemodialysis relies on osmosis and diffusion across a semi-permeable membrane to remove excess electrolytes and waste.

Question 7

Which of the following best describes the role of membrane transport proteins?

Accepted Answer

They facilitate the selective movement of specific ions and molecules across the membrane.

Question 8

Given the following concentrations: Intracellular $[K^+] \approx 125\ 	ext{mM}$, Extracellular $[K^+] \approx 5\ 	ext{mM}$, what is the direction of potassium movement if a potassium channel opens?

Accepted Answer

Potassium will move out of the cell.

Question 9

Which property of the cell membrane is most responsible for maintaining the difference in sodium and potassium concentrations between the intracellular and extracellular fluids?

Accepted Answer

Presence of membrane transport proteins such as the Na+/K+ ATPase pump

Question 10

A cell is placed in a hypotonic solution. What is the expected outcome?

Accepted Answer

Water will move into the cell, causing it to swell.

Question 11

Which of the following is NOT a function of the cell membrane?

Accepted Answer

Synthesizing proteins for cellular metabolism

Question 12

Which equation best represents the calculation of osmolarity for a solution containing $150\ 	ext{mM}$ NaCl?

Accepted Answer

$	ext{Osmolarity} = 150\ 	ext{mM} 	imes 2 = 300\ 	ext{mOsm/L}$

Question 13

Which of the following scenarios would most likely result in cell lysis?

Accepted Answer

Placing a cell in a hypotonic solution

Question 14

Which of the following statements about facilitated diffusion is correct?

Accepted Answer

It uses membrane proteins to move molecules down their concentration gradient.

Question 15

Which of the following best explains why proteins are more concentrated inside cells than in the extracellular fluid?

Accepted Answer

Cell membranes are impermeable to most proteins, preventing their exit.

Question 16

A patient is given a solution with an osmolarity of $400\ 	ext{mOsm/L}$. What is the likely effect on their red blood cells?

Accepted Answer

Cells will shrink due to water leaving the cell.

Question 17

Which of the following is a consequence of dysregulation of electrolyte movement in neurons?

Accepted Answer

Impaired action potential generation and transmission

Question 18

Which of the following is true regarding the movement of chloride ions ($Cl^-$) in the body?

Accepted Answer

Chloride moves passively down its concentration gradient through specific channels.

Question 19

Which of the following best describes the effect of a semi-permeable membrane on osmosis?

Accepted Answer

It allows water to move across the membrane while restricting solute movement.

Electrolyte Movement and Dysregulation: Physiology and Pathophysiology Study Notes

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