Q: Which equation correctly represents the phosphorylation reaction that provides energy for smooth muscle contraction?

$\mathrm{ATP} + \mathrm{H}_2\mathrm{O} \rightarrow \mathrm{ADP} + \mathrm{P}_i + \text{energy}$

Question 1

Which of the following best explains why osteoarthritis is more common in older adults?

Accepted Answer

Aging leads to decreased water content and elasticity in intervertebral discs, increasing susceptibility to joint degeneration.

Question 2

A patient presents with sudden lower back pain radiating down the leg after lifting a heavy object. Which anatomical structure is most likely involved?

Accepted Answer

Rupture of the annulus fibrosus in an intervertebral disc.

Question 3

Which of the following is a distinguishing feature of rheumatoid arthritis compared to osteoarthritis?

Accepted Answer

It is an autoimmune disease that commonly affects smaller joints like fingers and wrists.

Question 4

Which of the following best describes the role of the sarcoplasmic reticulum (SR) in smooth muscle contraction?

Accepted Answer

The SR stores calcium and releases it to trigger contraction, but is less prominent than in skeletal muscle.

Question 5

Which equation correctly represents the phosphorylation reaction that provides energy for smooth muscle contraction?

Accepted Answer

$\mathrm{ATP} + \mathrm{H}_2\mathrm{O} ightarrow \mathrm{ADP} + \mathrm{P}_i + 	ext{energy}$

Question 6

A patient with rheumatoid arthritis is likely to experience which of the following symptoms in the morning?

Accepted Answer

Joint swelling and morning stiffness.

Question 7

Which of the following is a function of the endomysium in skeletal muscle?

Accepted Answer

It surrounds individual muscle fibers, providing structural support and containing blood vessels.

Question 8

Which process is responsible for the removal of cytosolic calcium during smooth muscle relaxation?

Accepted Answer

Ca-ATPase pumps in the SR and cell membrane actively transport calcium out of the cytosol.

Question 9

Which of the following best describes the difference between single-unit and multi-unit smooth muscle?

Accepted Answer

Single-unit smooth muscle cells are connected by gap junctions, allowing coordinated contraction; multi-unit cells contract independently with little to no gap junctions.

Question 10

Which of the following is NOT a general characteristic of muscle tissue?

Accepted Answer

Calcification: Ability to deposit calcium in the extracellular matrix.

Question 11

A patient with osteoarthritis is most likely to have which of the following pathological changes in their joints?

Accepted Answer

Cartilage erosion and formation of bone spurs (osteophytes).

Question 12

Which of the following best explains the decreased flexibility in aging joints?

Accepted Answer

Ligaments and tendons shorten and weaken, reducing joint range of motion.

Question 13

Which of the following is a correct sequence of events in smooth muscle contraction?

Accepted Answer

Calcium entry, calmodulin activation, MLCK activation, phosphorylation of myosin heads, cross bridge formation, activation of myosin ATPase.

Question 14

Which of the following is a source of calcium for smooth muscle contraction?

Accepted Answer

Extracellular space via channels in the plasma membrane.

Question 15

Which connective tissue layer surrounds the entire skeletal muscle?

Accepted Answer

Epimysium

Question 16

Which of the following is a function of skeletal muscle in the human body?

Accepted Answer

Generating heat through contraction, contributing to body temperature regulation.

Question 17

Which of the following is a common effect of aging on joints?

Accepted Answer

Thinner articular cartilage and decreased joint lubrication.

Question 18

Which of the following best describes the arrangement of smooth muscle in hollow organs?

Accepted Answer

Longitudinal layer runs parallel to the organ's axis, circular layer runs perpendicular.

Question 19

Which of the following is a correct function of the perimysium in skeletal muscle?

Accepted Answer

It surrounds bundles of muscle fibers (fascicles) and contains blood vessels.

Anatomy & Physiology Study Notes: Joints, Muscle Tissue, and Contraction

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