Q: Which equation best represents the Nernst equation used to calculate the equilibrium potential for an ion across a membrane?

$$E = \frac{RT}{zF} \ln \left( \frac{[\text{ion}]_{\text{out}}}{[\text{ion}]_{\text{in}}} \right)$$

Question 1

Which of the following best defines homeostasis in the context of human physiology?

Accepted Answer

The maintenance of a stable internal environment despite changes in the external environment.

Question 2

Which of the following is NOT a primary tissue type found in the human body?

Accepted Answer

Adipose tissue

Question 3

A patient is experiencing muscle weakness due to impaired active transport of sodium and potassium ions. Which equation best represents the energy-dependent process responsible for this transport?

Accepted Answer

$$3\mathrm{Na^+_{in}} + 2\mathrm{K^+_{out}} + \mathrm{ATP} \rightarrow 3\mathrm{Na^+_{out}} + 2\mathrm{K^+_{in}} + \mathrm{ADP} + \mathrm{P_i}$$

Question 4

Which of the following best describes the difference between passive and active transport across the cell membrane?

Accepted Answer

Passive transport moves molecules down their concentration gradient without energy input, while active transport moves molecules against their gradient using energy.

Question 5

Which of the following is a function of gap junctions in cardiac muscle cells?

Accepted Answer

They allow for the rapid transmission of electrical signals between cells.

Question 6

A researcher is studying the effect of a toxin that blocks ligand-gated ion channels. Which process would be most directly affected?

Accepted Answer

The generation of action potentials in neurons.

Question 7

Which of the following best describes the role of myelin in the nervous system?

Accepted Answer

Myelin increases the speed of action potential conduction along axons by insulating them.

Question 8

Which equation best represents the Nernst equation used to calculate the equilibrium potential for an ion across a membrane?

Accepted Answer

$$E = \frac{RT}{zF} \ln \left( \frac{[	ext{ion}]_{	ext{out}}}{[	ext{ion}]_{	ext{in}}} ight)$$

Question 9

Which of the following best describes the process of depolarization during an action potential?

Accepted Answer

Sodium ions rapidly enter the neuron, making the inside more positive.

Question 10

A patient is diagnosed with a disorder affecting neurotransmitter storage. Where are neurotransmitters typically stored before release?

Accepted Answer

In synaptic vesicles within the axon terminal

Question 11

Which of the following is a correct sequence of events in chemical synaptic transmission?

Accepted Answer

Action potential arrives at axon terminal → neurotransmitter released → neurotransmitter binds to postsynaptic receptor → postsynaptic potential generated

Question 12

Which of the following best describes the difference between afferent and efferent neurons?

Accepted Answer

Afferent neurons carry sensory information to the central nervous system, while efferent neurons carry motor commands away from it.

Question 13

Which of the following is a characteristic of graded potentials, but NOT action potentials?

Accepted Answer

They can summate and vary in amplitude.

Question 14

Which of the following mechanisms is involved in signal transduction for membrane enzymes such as tyrosine kinase?

Accepted Answer

Phosphorylation of intracellular proteins following ligand binding to the receptor.

Question 15

Which of the following best describes the function of the absolute refractory period of the axon membrane?

Accepted Answer

It prevents the neuron from firing another action potential until the membrane potential returns to resting.

Question 16

Which of the following is a correct description of the three phases of an action potential?

Accepted Answer

Depolarization, repolarization, hyperpolarization

Question 17

Which of the following is a function of G protein-coupled receptors (GPCRs) in cell signaling?

Accepted Answer

They activate intracellular second messengers upon ligand binding.

Question 18

Which of the following types of gated ion channels is primarily responsible for the rapid depolarization phase of the neuronal action potential?

Accepted Answer

Voltage-gated sodium channels

Question 19

Which of the following best describes the difference between autocrine, paracrine, and endocrine modes of cell signaling?

Accepted Answer

Autocrine signals act on the same cell that secreted them; paracrine signals act on nearby cells; endocrine signals act on distant cells via the bloodstream.

Question 20

A patient has a mutation that impairs the function of voltage-gated potassium channels in neurons. Which phase of the action potential would be most affected?

Accepted Answer

Repolarization

Fundamental Concepts in Anatomy & Physiology: Cells, Tissues, Membranes, and Neural Signaling

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