Question 1

Which of the following best describes the primary contributors to the resting membrane potential in neurons?

Accepted Answer

The sodium-potassium pump, ion channels, and selective permeability of the cell membrane

Question 2

A patient is experiencing muscle weakness due to prolonged opening of chloride channels in their muscle cell membranes. Which phenomenon is most likely responsible for this symptom?

Accepted Answer

Hyperpolarization and action potentials

Question 3

Which statement accurately reflects the 'all-or-none principle' in neuronal action potentials?

Accepted Answer

Action potentials only occur if the membrane potential reaches a specific threshold.

Question 4

During the absolute refractory period, which of the following is true regarding the generation of action potentials?

Accepted Answer

No stimulus, regardless of strength, can generate another action potential.

Question 5

Which equation best represents the Nernst equation for calculating the equilibrium potential of potassium ($$K^+) $$ions across a membrane?

Accepted Answer

$$E_K = \frac{RT}{zF} \ln \left( \frac{[K^+]_{out}}{[K^+]_{in}} \right)$$

Question 6

A patient presents with loss of pain sensation in their upper lip after dental surgery. Which type of receptor is most likely affected?

Accepted Answer

Free nerve ending

Question 7

Which of the following best explains why the brain allocates more space to the upper lip in the sensory cortex?

Accepted Answer

The upper lip has a higher density of sensory receptors, requiring more cortical representation.

Question 8

Which of the following is a characteristic of graded potentials?

Accepted Answer

They vary in magnitude depending on stimulus strength and can be depolarizing or hyperpolarizing.

Question 9

A patient enters a dark room and gradually becomes able to see after several minutes. Which type of receptor adaptation is responsible for this phenomenon?

Accepted Answer

Tonic receptor adaptation

Question 10

Which of the following best describes the role of pacemaker cells in cardiac muscle?

Accepted Answer

They spontaneously generate action potentials without external input.

Question 11

Which cranial nerve is classified as purely sensory and is responsible for vision?

Accepted Answer

Optic nerve (CN II)

Question 12

A patient is unable to track moving objects with their eyes, but can still see stationary objects clearly. Which brain region is most likely affected?

Accepted Answer

Superior colliculus

Question 13

Which of the following is true regarding the relative refractory period of an action potential?

Accepted Answer

A stronger-than-normal stimulus is required to generate an action potential.

Question 14

Which of the following best explains the concept of 'graded potentials' in neurons?

Accepted Answer

They are local changes in membrane potential that vary in amplitude and can summate.

Question 15

Which of the following is a correct statement about the role of the sodium-potassium pump in maintaining the resting membrane potential?

Accepted Answer

It moves three sodium ions out and two potassium ions into the cell, creating an electrochemical gradient.

Question 16

Which of the following equations represents the Goldman-Hodgkin-Katz equation for membrane potential?

Accepted Answer

$$V_m = \frac{RT}{F} \ln \left( \frac{P_{K^+}[K^+]_{out} + P_{Na^+}[Na^+]_{out} + P_{Cl^-}[Cl^-]_{in}}{P_{K^+}[K^+]_{in} + P_{Na^+}[Na^+]_{in} + P_{Cl^-}[Cl^-]_{out}} \right)$$

Question 17

A patient is unable to feel pain in their hand after a burn injury. Which type of receptor is most likely damaged?

Accepted Answer

Free nerve ending

Question 18

Which of the following best describes the function of tonic receptors?

Accepted Answer

They respond continuously to prolonged or constant stimuli.

Question 19

Which of the following is a real-life example of referred pain?

Accepted Answer

Pain felt in the left arm during a myocardial infarction (heart attack)

Resting Membrane Potential and Neural Physiology: Key Concepts

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