Question 1

Which of the following best describes a synovial joint compared to fibrous and cartilaginous joints?

Accepted Answer

Synovial joints have a joint cavity filled with synovial fluid, surrounded by an articular capsule, and allow free movement.

Question 2

A patient presents with difficulty performing dorsiflexion at the ankle. Which movement is most likely impaired?

Accepted Answer

Moving the foot upward, toward the shin

Question 3

Which synovial joint type allows movement in three planes and is classified as multiaxial?

Accepted Answer

Ball-and-socket joint

Question 4

In the human body, the elbow joint acts as a lever when lifting a weight. If the fulcrum is at the elbow, the load is in the hand, and the effort is applied by the biceps muscle, what class of lever is this?

Accepted Answer

Third class lever

Question 5

Which lever class provides the greatest mechanical advantage ($$MA$$), and why?

Accepted Answer

Second class lever, because the load is between the fulcrum and effort

Question 6

Which of the following best describes the process of depolarization during an action potential?

Accepted Answer

Sodium ions move into the cell, making the membrane potential less negative

Question 7

What is the primary function of the sodium/potassium pump ($$	ext{Na}^+/	ext{K}^+$$ ATPase$) in maintaining the resting membrane potential?

Accepted Answer

It actively transports sodium out of the cell and potassium into the cell, maintaining the electrochemical gradient

Question 8

A muscle fiber is unable to relax after contraction. Which malfunction is most likely responsible?

Accepted Answer

Acetylcholine esterase is not breaking down acetylcholine at the neuromuscular junction

Question 9

Which of the following best describes the sliding filament theory of muscle contraction?

Accepted Answer

Actin filaments slide past myosin filaments, shortening the sarcomere

Question 10

Which component of the sarcomere marks the boundary between adjacent sarcomeres?

Accepted Answer

Z disc

Question 11

During muscle contraction, which molecule binds to troponin to initiate the exposure of binding sites on actin?

Accepted Answer

Calcium

Question 12

Which of the following is a real-life anatomical example of a second class lever?

Accepted Answer

Standing on tiptoe (plantar flexion)

Question 13

Which muscle tissue type is involuntary and contains intercalated discs?

Accepted Answer

Cardiac muscle

Question 14

What is the significance of the length-tension relationship in muscle contractile proteins?

Accepted Answer

Muscle force is greatest when the muscle is at an optimal length, allowing maximal overlap of actin and myosin

Question 15

Which of the following best describes the role of mitochondria in muscle cells during contraction?

Accepted Answer

Mitochondria produce ATP required for crossbridge cycling and maintaining ion gradients

Question 16

Which of the following is TRUE regarding the calcium-calmodulin complex in smooth muscle contraction?

Accepted Answer

It activates myosin light chain kinase, leading to phosphorylation of myosin and contraction

Question 17

A patient has chronic hyperpolarization of their muscle cell membranes. Which of the following is a likely consequence?

Accepted Answer

Decreased excitability, making it harder to generate action potentials

Question 18

Which of the following best describes the function of voltage-gated channels in muscle contraction?

Accepted Answer

They open in response to changes in membrane potential, allowing ions to flow and propagate action potentials

Question 19

Which of the following is a benefit of having multiple motor unit innervation in a muscle?

Accepted Answer

It enables fine control of muscle force and gradation of contraction

Question 20

Which of the following is TRUE regarding the process of crossbridge formation during muscle contraction?

Accepted Answer

Myosin heads bind to actin after ATP is hydrolyzed, forming a crossbridge

Joints, Muscle Structure, and Action Potentials: Study Guide for Anatomy & Physiology

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