Question 1

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

Accepted Answer

Troponin binds calcium ions, causing a conformational change that moves tropomyosin away from actin's binding sites.

Question 2

A muscle fiber is stimulated repeatedly at a frequency that does not allow complete relaxation between stimuli. Which phenomenon is most likely to occur?

Accepted Answer

Wave summation

Question 3

During excitation-contraction coupling, which sequence correctly describes the events leading to muscle contraction?

Accepted Answer

Acetylcholine release → depolarization of sarcolemma → calcium release from sarcoplasmic reticulum → cross-bridge formation

Question 4

Which connective tissue sheath surrounds individual muscle fibers?

Accepted Answer

Endomysium

Question 5

A patient presents with muscle weakness. Upon investigation, it is found that acetylcholine is not being released at the neuromuscular junction. Which structure is most likely malfunctioning?

Accepted Answer

Axon terminal

Question 6

Which of the following best describes the length-tension relationship in skeletal muscle?

Accepted Answer

Muscle tension is highest when the muscle is at its resting length, allowing optimal overlap of actin and myosin.

Question 7

Which of the following is a function of the myelin sheath in the nervous system?

Accepted Answer

It increases the speed of action potential propagation by insulating axons.

Question 8

Which neuroglia cell type is responsible for myelinating axons in the peripheral nervous system (PNS)?

Accepted Answer

Schwann cells

Question 9

A neuron receives a stimulus that causes its membrane potential to change from $$-70\ 	ext{mV} to$$ $$-55\ 	ext{mV}. $$What is this process called?

Accepted Answer

Depolarization

Question 10

Which of the following best describes the absolute refractory period of an action potential?

Accepted Answer

A period when voltage-gated sodium channels are inactivated and no new action potential can be generated.

Question 11

Which of the following is NOT a structural component of the neuromuscular junction?

Accepted Answer

Terminal cisternae

Question 12

Which equation best represents the calculation of the resting membrane potential ($$V_m) $$based on ion concentrations and permeability?

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 13

Which term describes a bundle of axons in the central nervous system (CNS)?

Accepted Answer

Tract

Question 14

A muscle responsible for stabilizing a joint during movement, but not directly causing the movement, is called a:

Accepted Answer

Fixator

Question 15

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

Accepted Answer

Myelinated axons allow action potentials to jump between nodes of Ranvier via saltatory conduction.

Question 16

Which of the following is TRUE regarding the function of acetylcholine at the neuromuscular junction?

Accepted Answer

Acetylcholine binds to receptors on the sarcolemma, causing sodium ions to enter the muscle fiber and initiate depolarization.

Question 17

Which of the following best describes the difference between fused and unfused tetanus in muscle contraction?

Accepted Answer

Fused tetanus is a sustained contraction with no relaxation between stimuli, while unfused tetanus shows partial relaxation.

Question 18

Which of the following is a correct pairing of neuroglia type and its location?

Accepted Answer

Microglia – CNS

Question 19

A nerve impulse travels from one neuron to another. Which event occurs at the synaptic cleft to facilitate this transmission?

Accepted Answer

Neurotransmitters are released from the presynaptic neuron and bind to receptors on the postsynaptic membrane.

Anatomy & Physiology I Lab: Muscular and Nervous Systems Study Guide

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