Question 1

Which of the following best describes the role of the sarcoplasmic reticulum in skeletal muscle contraction?

Accepted Answer

It stores and releases calcium ions ($$\mathrm{Ca$$^{2+}$$}) $$necessary for muscle contraction.

Question 2

During the sliding filament mechanism of muscle contraction, which event occurs immediately after calcium binds to troponin?

Accepted Answer

Tropomyosin shifts to expose myosin-binding sites on actin.

Question 3

A patient is exposed to a toxin that blocks acetylcholinesterase at the neuromuscular junction. What is the most likely effect on muscle contraction?

Accepted Answer

Prolonged muscle contraction due to continuous stimulation by acetylcholine.

Question 4

Which of the following best explains why cardiac muscle cells are resistant to fatigue compared to skeletal muscle cells?

Accepted Answer

Cardiac muscle cells have more mitochondria and rely heavily on aerobic respiration.

Question 5

Which of the following is the correct sequence of events during an action potential in a neuron?

Accepted Answer

Depolarization $$\rightarrow$$ Repolarization $$\rightarrow$$ Hyperpolarization $$\rightarrow$$ Resting membrane potential

Question 6

Which of the following best describes the function of Schwann cells in the peripheral nervous system?

Accepted Answer

They form myelin sheaths around axons, increasing the speed of nerve impulse conduction.

Question 7

A muscle fiber is unable to relax after contraction. Which of the following is the most likely cause?

Accepted Answer

Failure of calcium ions ($$\mathrm{Ca$$^{2+}$$}) to be $$actively transported back into the sarcoplasmic reticulum.

Question 8

Which of the following statements about the refractory period of a neuron is correct?

Accepted Answer

It is the period during which a neuron cannot initiate another action potential.

Question 9

Which of the following best describes the difference between continuous and saltatory conduction in neurons?

Accepted Answer

Saltatory conduction occurs in myelinated axons and is faster because the action potential jumps from node to node.

Question 10

Which of the following is a function of the blood-brain barrier?

Accepted Answer

It restricts the passage of certain substances from the blood into the CNS.

Question 11

Which of the following best describes the role of ATP in muscle contraction?

Accepted Answer

ATP binds to myosin, causing it to detach from actin after the power stroke.

Question 12

A patient presents with muscle weakness and is diagnosed with myasthenia gravis, an autoimmune disorder affecting acetylcholine receptors. Which of the following best explains the physiological basis of their symptoms?

Accepted Answer

Reduced number of functional acetylcholine receptors impairs neuromuscular transmission.

Question 13

Which of the following is the correct formula for calculating the resting membrane potential ($$V_m) $$using the Nernst equation for potassium ions ($$K^+$$)?

Accepted Answer

$$V_m = \frac{RT}{zF} \ln \left( \frac{[K^+]_{	ext{outside}}}{[K^+]_{	ext{inside}}} ight)$$

Question 14

Which of the following best explains why summation of graded potentials is necessary for the generation of an action potential?

Accepted Answer

A single graded potential is usually insufficient to reach the threshold; multiple inputs are needed to depolarize the membrane to threshold.

Question 15

Which of the following is a characteristic unique to smooth muscle tissue?

Accepted Answer

It can contract without direct stimulation from the nervous system.

Question 16

Which of the following best describes the function of the T-tubules in skeletal muscle fibers?

Accepted Answer

They conduct action potentials deep into the muscle fiber, triggering calcium release.

Question 17

Which of the following is the correct order of events at the neuromuscular junction leading to muscle contraction?

Accepted Answer

Action potential arrives at axon terminal $$\rightarrow$$ Acetylcholine is released $$\rightarrow$$ Acetylcholine binds to receptors on sarcolemma $$\rightarrow$$ Muscle fiber depolarizes

Question 18

Which of the following best explains the physiological basis for the oxygen debt (excess post-exercise oxygen consumption, EPOC) observed after intense exercise?

Accepted Answer

Oxygen is required to restore ATP, creatine phosphate, and remove lactic acid accumulated during exercise.

Question 19

Which of the following best describes the function of the axon hillock in a neuron?

Accepted Answer

It is the site where action potentials are initiated.

Question 20

Which of the following is a correct statement about the difference between electrical and chemical synapses?

Accepted Answer

Electrical synapses transmit signals via gap junctions, while chemical synapses use neurotransmitters.

BIO 141 Unit 3 Study Guide: Muscle Tissue and Nervous System

Study Guide - Practice Questions

Study Guide - Flashcards