Question 1

Which of the following best describes the function of oligodendrocytes in the central nervous system?

Accepted Answer

They produce myelin sheaths around axons, increasing the speed of action potential conduction.

Question 2

A neuron has the following ion concentrations: $$[K^+]_{in} = 140\,mM$$, $$[K^+]_{out} = 5\,mM$$, $$[Na^+]_{in} = 15\,mM$$, $$[Na^+]_{out} = 145\,mM. $$Using the Nernst equation, which ion has a greater influence on the resting membrane potential and why?

Accepted Answer

Potassium, because the membrane is more permeable to $$K^+ at $$rest.

Question 3

Which of the following events occurs first during the generation of an action potential?

Accepted Answer

The membrane potential reaches threshold, causing voltage-gated sodium channels to open.

Question 4

A patient is given a drug that blocks acetylcholinesterase at the neuromuscular junction. What is the most likely physiological effect?

Accepted Answer

Prolonged muscle contraction due to increased acetylcholine in the synaptic cleft.

Question 5

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

Accepted Answer

Myelin allows saltatory conduction, where action potentials jump between nodes of Ranvier.

Question 6

Which neurotransmitter is primarily inhibitory in the central nervous system and acts through chloride ion channels?

Accepted Answer

GABA

Question 7

A patient suffers a stroke affecting the left precentral gyrus. Which function is most likely to be impaired?

Accepted Answer

Voluntary movement of the right side of the body

Question 8

Which of the following best describes the function of the limbic system?

Accepted Answer

Integration of emotional responses, memory, and motivation

Question 9

Which of the following statements about the blood-brain barrier is correct?

Accepted Answer

It is formed by astrocytes and tight junctions between endothelial cells.

Question 10

A person is unable to feel pain in their left hand after a spinal cord injury. Which pathway is most likely damaged?

Accepted Answer

Spinothalamic (anterolateral) pathway

Question 11

Which of the following best describes the difference between tonic and phasic sensory receptors?

Accepted Answer

Tonic receptors maintain a sustained response to a constant stimulus, while phasic receptors respond only to changes in stimulus.

Question 12

Which of the following is a property of A-delta fibers in somatosensory pathways?

Accepted Answer

They are myelinated and transmit fast, sharp pain.

Question 13

A patient with damage to the vestibular apparatus would most likely experience which of the following symptoms?

Accepted Answer

Difficulty maintaining balance and spatial orientation

Question 14

Which of the following best explains the gate control theory of pain modulation?

Accepted Answer

Non-painful input closes the 'gates' to painful input at the spinal cord, reducing pain perception.

Question 15

Which of the following is true regarding the sympathetic division of the autonomic nervous system?

Accepted Answer

It has short preganglionic and long postganglionic fibers.

Question 16

Which of the following best describes the role of the neuromuscular junction?

Accepted Answer

It is the site where a motor neuron communicates with a skeletal muscle fiber to initiate contraction.

Question 17

During a muscle twitch, which event occurs immediately after the release of calcium ions from the sarcoplasmic reticulum?

Accepted Answer

Calcium binds to troponin, causing a conformational change that moves tropomyosin.

Question 18

Which of the following best explains why cardiac muscle cells can contract in a coordinated fashion without direct neural input?

Accepted Answer

They are connected by gap junctions, allowing action potentials to spread rapidly between cells.

Question 19

A patient presents with muscle weakness and rapid fatigue during exercise, but recovers after rest. Which type of muscle fatigue is most likely involved?

Accepted Answer

Peripheral fatigue due to depletion of ATP and accumulation of metabolic byproducts in the muscle.

Question 20

Which of the following is an example of a monosynaptic reflex?

Accepted Answer

Patellar (knee-jerk) reflex

Comprehensive Study Notes: Nervous, Sensory, Motor, and Muscular Physiology

Guida di studio - Domande di pratica

Study guide - Flashcard