Q: A muscle fiber is stimulated and generates an action potential. Which equation best represents the Nernst equation for calculating the equilibrium potential of an ion?

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

Q: Which equation best represents the calculation of the resting membrane potential using the Goldman-Hodgkin-Katz equation?

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

Question 1

Which protein filament is primarily responsible for muscle contraction by sliding past another filament during the cross-bridge cycle?

Accepted Answer

Myosin

Question 2

A patient is experiencing muscle weakness due to insufficient calcium release from the sarcoplasmic reticulum. Which structure is most directly responsible for storing and releasing calcium in skeletal muscle fibers?

Accepted Answer

Sarcoplasmic reticulum

Question 3

During a marathon, a runner's muscles begin to fatigue. Which ATP-producing pathway is most likely to be active under anaerobic conditions?

Accepted Answer

Glycolysis

Question 4

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

Accepted Answer

It stimulates muscle contraction by binding to receptors on the muscle cell membrane.

Question 5

A muscle fiber is stimulated and generates an action potential. Which equation best represents the Nernst equation for calculating the equilibrium potential of an ion?

Accepted Answer

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

Question 6

Which of the following is the correct order of events in excitation-contraction coupling in skeletal muscle?

Accepted Answer

Action potential, acetylcholine release, acetylcholine binding, calcium release, cross-bridge formation

Question 7

A patient with myasthenia gravis has antibodies that block acetylcholine receptors. What is the most likely effect on muscle contraction?

Accepted Answer

Decreased ability to initiate muscle contractions

Question 8

Which structure in the sarcomere shortens during muscle contraction?

Accepted Answer

I band

Question 9

A muscle cell is unable to produce ATP due to mitochondrial dysfunction. Which process will be most directly affected?

Accepted Answer

Formation of cross-bridges between actin and myosin

Question 10

Which of the following best explains why the resting membrane potential of a neuron is negative?

Accepted Answer

Potassium ions leak out of the cell more easily than sodium ions enter.

Question 11

A patient is given a drug that blocks voltage-gated sodium channels. What effect will this have on the generation of action potentials in neurons?

Accepted Answer

Action potentials will be inhibited.

Question 12

Which neurotransmitter is most commonly associated with excitatory postsynaptic potentials (EPSPs) in the central nervous system?

Accepted Answer

Glutamate

Question 13

A patient presents with muscle cramps after intense exercise. Which ion is most likely depleted, leading to impaired muscle relaxation?

Accepted Answer

Magnesium

Question 14

Which of the following best describes the function of the blood-brain barrier?

Accepted Answer

It prevents the entry of most large and hydrophilic molecules into the brain.

Question 15

Which anatomical landmark of the cerebral cortex separates primary motor areas from somatosensory areas?

Accepted Answer

Central sulcus

Question 16

A patient has damage to the precentral gyrus. Which function is most likely to be impaired?

Accepted Answer

Voluntary motor control

Question 17

Which equation best represents the calculation of the resting membrane potential using the Goldman-Hodgkin-Katz equation?

Accepted Answer

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

Question 18

Which of the following best describes the difference between graded potentials and action potentials?

Accepted Answer

Graded potentials can summate, while action potentials cannot.

Question 19

A patient is unable to move their right arm after a stroke. Which region of the brain is most likely affected?

Accepted Answer

Left primary motor cortex

Comprehensive Study Guide: Muscle, Nervous Tissue, and Brain (Anatomy & Physiology)

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