Q: A neuron is at rest with a membrane potential of $-70\ \mathrm{mV}$. Which ions are primarily responsible for maintaining this resting membrane potential?

Potassium (K\textsuperscript{+}) and sodium (Na\textsuperscript{+})

Q: Which of the following best describes the role of the sodium-potassium pump ($\mathrm{Na^+/K^+}$ ATPase) in maintaining cell homeostasis?

It actively transports 3 Na\textsuperscript{+} ions out of the cell and 2 K\textsuperscript{+} ions into the cell, using ATP

Q: During an action potential, which event occurs immediately after the membrane potential reaches its peak?

Voltage-gated K\textsuperscript{+} channels open, allowing K\textsuperscript{+} to exit the cell

Question 1

Which of the following best describes the main function of homeostatic mechanisms in the human body?

Accepted Answer

To maintain stable internal conditions despite external changes

Question 2

A patient is given an intravenous solution that is hypertonic relative to their plasma. What is the most likely effect on their red blood cells?

Accepted Answer

Water will leave the cells, causing them to shrink (crenate)

Question 3

Which of the following best characterizes facilitated diffusion across a cell membrane?

Accepted Answer

Movement of molecules down their concentration gradient via a membrane protein, without energy input

Question 4

A neuron is at rest with a membrane potential of $-70\ \mathrm{mV}$. Which ions are primarily responsible for maintaining this resting membrane potential?

Accepted Answer

Potassium (K	extsuperscript{+}) and sodium (Na	extsuperscript{+})

Question 5

Which of the following best describes the role of the sodium-potassium pump ($\mathrm{Na^+/K^+}$ ATPase) in maintaining cell homeostasis?

Accepted Answer

It actively transports 3 Na	extsuperscript{+} ions out of the cell and 2 K	extsuperscript{+} ions into the cell, using ATP

Question 6

A patient is experiencing muscle weakness due to low extracellular potassium ($\mathrm{K^+}$) levels. Which of the following best explains this effect?

Accepted Answer

Low $\mathrm{K^+}$ hyperpolarizes the resting membrane potential, making it harder to generate action potentials

Question 7

Which of the following is an example of negative feedback in human physiology?

Accepted Answer

Increased blood glucose stimulates insulin release, which lowers blood glucose

Question 8

During an action potential, which event occurs immediately after the membrane potential reaches its peak?

Accepted Answer

Voltage-gated K	extsuperscript{+} channels open, allowing K	extsuperscript{+} to exit the cell

Question 9

Which of the following best describes the difference between simple diffusion and facilitated diffusion?

Accepted Answer

Facilitated diffusion requires a membrane protein, while simple diffusion does not

Question 10

A cell is placed in a solution and begins to swell. Which of the following best describes the tonicity of the solution relative to the cell?

Accepted Answer

The solution is hypotonic

Question 11

Which of the following best explains why glucose cannot cross the plasma membrane by simple diffusion?

Accepted Answer

Glucose is too large and polar to pass through the lipid bilayer without a transporter

Question 12

Which of the following is a correct statement about the movement of water across cell membranes?

Accepted Answer

Water moves by osmosis from areas of low solute concentration to areas of high solute concentration

Question 13

A patient is given a drug that blocks voltage-gated Na	extsuperscript{+} channels. What is the most likely effect on their neurons?

Accepted Answer

Action potentials will not be generated

Question 14

Which of the following best describes the relationship between extracellular and intracellular fluid compartments?

Accepted Answer

Extracellular fluid includes plasma and interstitial fluid, while intracellular fluid is inside cells

Question 15

Which of the following is an example of active transport?

Accepted Answer

Movement of Na	extsuperscript{+} out of the cell via the sodium-potassium pump

Question 16

A patient with severe dehydration is given an intravenous solution. Which type of solution would best restore their blood volume without causing red blood cells to shrink or swell?

Accepted Answer

An isotonic solution

Question 17

Which of the following best describes the effect of opening ligand-gated chloride (Cl	extsuperscript{--}) channels on a neuron's membrane potential?

Accepted Answer

The membrane potential becomes more negative (hyperpolarization)

Question 18

Which of the following best explains why the resting membrane potential is closer to the equilibrium potential of K	extsuperscript{+} than Na	extsuperscript{+}?

Accepted Answer

The membrane is more permeable to K	extsuperscript{+} than to Na	extsuperscript{+} at rest

Question 19

A cell is placed in a solution containing a high concentration of non-penetrating solute. Which equation would you use to calculate the osmotic pressure exerted by the solute?

Accepted Answer

$\Pi = iMRT$

Question 20

Which of the following best describes the sequence of events during an action potential?

Accepted Answer

Depolarization, repolarization, hyperpolarization

Anatomy & Physiology I: Syllabus and Core Study Notes

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