Question 1

Which of the following best explains why the resting membrane potential ($$V_m) of a $$typical neuron is closer to the equilibrium potential for potassium ($$E_K) $$than for sodium ($$E_{Na}$$)?

Accepted Answer

Because the membrane is much more permeable to K⁺ than to Na⁺ at rest due to K⁺ leak channels.

Question 2

A patient is diagnosed with myasthenia gravis, an autoimmune disease that targets acetylcholine (ACh) receptors at the neuromuscular junction. Which of the following best describes the physiological consequence at the synapse?

Accepted Answer

Reduced postsynaptic depolarization due to fewer functional ACh receptors, leading to muscle weakness.

Question 3

Which sequence correctly describes the events at a chemical synapse following the arrival of an action potential at the presynaptic terminal?

Accepted Answer

Voltage-gated Ca²⁺ channels open → Ca²⁺ influx → vesicle fusion → neurotransmitter release → postsynaptic receptor binding

Question 4

A neuron receives simultaneous excitatory postsynaptic potentials (EPSPs) from three different presynaptic neurons. This is an example of which process?

Accepted Answer

Spatial summation

Question 5

Which of the following best describes the role of the Na⁺/K⁺ pump in maintaining neuronal function?

Accepted Answer

It uses ATP to move 3 Na⁺ out of the cell and 2 K⁺ into the cell, maintaining ion gradients essential for action potentials.

Question 6

During the rising phase of an action potential, which ion movement is primarily responsible for the rapid depolarization of the membrane?

Accepted Answer

Na⁺ influx through voltage-gated Na⁺ channels

Question 7

Which of the following is a key function of astrocytes in the central nervous system?

Accepted Answer

Maintaining the blood–brain barrier and regulating extracellular ion balance

Question 8

A toxin blocks voltage-gated K⁺ channels in a neuron. What is the most likely effect on the action potential?

Accepted Answer

The falling phase (repolarization) will be delayed, prolonging the action potential.

Question 9

Which of the following best explains why myelinated axons conduct action potentials faster than unmyelinated axons?

Accepted Answer

Myelin insulates the axon, allowing action potentials to jump between nodes of Ranvier (saltatory conduction).

Question 10

A muscle cell is deprived of ATP. Which of the following best describes the immediate consequence for muscle contraction?

Accepted Answer

Myosin heads cannot detach from actin, resulting in rigor (persistent contraction).

Question 11

Which of the following is a distinguishing feature of cardiac muscle compared to skeletal and smooth muscle?

Accepted Answer

Presence of intercalated discs that allow electrical and mechanical coupling between cells

Question 12

Which brain region acts as the main relay station for sensory information on its way to the cerebral cortex?

Accepted Answer

Thalamus

Question 13

A patient has damage to the prefrontal cortex. Which of the following symptoms is most likely?

Accepted Answer

Impaired decision making and emotional regulation

Question 14

Which of the following best describes the role of the suprachiasmatic nucleus (SCN) in the hypothalamus?

Accepted Answer

It synchronizes circadian rhythms using light input from the eyes.

Question 15

Which of the following is true regarding long-term potentiation (LTP) in the nervous system?

Accepted Answer

It is a lasting increase in synaptic strength, often involving NMDA and AMPA glutamate receptors.

Question 16

Which of the following best describes the function of the enteric nervous system (ENS)?

Accepted Answer

It coordinates digestive tract activity locally, often independently of the CNS.

Question 17

A researcher records the membrane voltage $$V(t) of a $$neuron during an action potential. According to calculus, at the peak of the action potential, which of the following is true?

Accepted Answer

$$V'(t^*) = 0$$ and $$V''(t^*) \u003c 0$$, where $$t^* is $$the time of the peak.

Question 18

Which of the following is a correct pairing of glial cell type and its primary function?

Accepted Answer

Microglia — immune defense and phagocytosis in the CNS

Question 19

Which of the following best explains why the refractory period ensures unidirectional propagation of action potentials along an axon?

Accepted Answer

Na⁺ channels are inactivated immediately after an action potential, preventing immediate re-firing in the same region.

Neurons, Synapses, Muscle, and Nervous System Organization: Study Notes

Study Guide - Practice Questions

Study Guide - Flashcards