Question 1

Which of the following best describes the main function of osteoclasts in bone tissue?

Accepted Answer

They break down bone tissue by releasing acids and enzymes.

Question 2

A patient presents with bones that are soft and prone to bending. Laboratory tests reveal a deficiency in vitamin D. Which disease is most likely present, and how does it differ from osteoporosis?

Accepted Answer

Osteomalacia; it involves defective mineralization of bone matrix, while osteoporosis involves loss of bone mass.

Question 3

Which hormone increases blood calcium levels by stimulating osteoclast activity, and what is the negative feedback loop that regulates it?

Accepted Answer

Parathyroid hormone (PTH); it is released when blood calcium is low and stimulates osteoclasts until calcium returns to normal.

Question 4

A long bone is fractured. Which process is responsible for the initial formation of new bone tissue at the fracture site, and what type of cells are primarily involved?

Accepted Answer

Intramembranous ossification; osteoblasts

Question 5

Which of the following best explains why cartilage must be replaced with bone during growth plate closure?

Accepted Answer

Cartilage is too flexible to support the mechanical demands of the adult skeleton.

Question 6

A 12-year-old child is experiencing rapid growth. Which hormone is primarily responsible for stimulating this bone growth, and what is its effect on the growth plate?

Accepted Answer

Growth hormone; it stimulates chondrocyte proliferation at the growth plate.

Question 7

Which of the following best describes the difference between compact bone and spongy bone?

Accepted Answer

Compact bone is dense and forms the outer layer of bones, while spongy bone contains trabeculae and is found inside bones.

Question 8

A patient has a fracture that is not healing properly. Which of the following is the most likely reason for delayed bone healing?

Accepted Answer

Insufficient blood supply to the fracture site

Question 9

Which of the following best describes the role of calcium ions ($$Ca^{2+}) in $$muscle contraction?

Accepted Answer

They bind to troponin, exposing binding sites on actin for myosin.

Question 10

During aerobic respiration in muscle cells, which of the following is the correct equation for the breakdown of glucose?

Accepted Answer

$$C_6H_{12}O_6$ + 6O_2 \rightarrow 6CO_2 + 6H_2O + ATP$$

Question 11

Which of the following best describes a motor unit in the muscular system?

Accepted Answer

A motor neuron and all the muscle fibers it innervates

Question 12

A patient is unable to move their arm after a nerve injury. Which part of the neuromuscular junction is most likely affected?

Accepted Answer

The release of acetylcholine from the motor neuron

Question 13

Which of the following is a by-product of anaerobic respiration in muscle cells?

Accepted Answer

Lactic acid

Question 14

Which of the following best explains why muscle tone is important for posture?

Accepted Answer

Muscle tone keeps muscles partially contracted, stabilizing joints and maintaining posture.

Question 15

A patient develops rigor mortis after death. What is the primary cause of this phenomenon?

Accepted Answer

Lack of ATP prevents detachment of myosin heads from actin

Question 16

Which of the following best describes the difference between axial and appendicular bones?

Accepted Answer

Axial bones include the skull, vertebral column, and rib cage; appendicular bones include the limbs and girdles.

Question 17

Which of the following is the correct order of events in muscle contraction?

Accepted Answer

Calcium binds to troponin → Myosin binds to actin → ATP is hydrolyzed → Sarcomere shortens

Question 18

Which of the following best describes the structural classification of a synovial joint?

Accepted Answer

A joint where bones are separated by a fluid-filled cavity and enclosed by a joint capsule

Question 19

A patient is diagnosed with osteoarthritis. Which of the following best explains the underlying pathology?

Accepted Answer

Degeneration of articular cartilage in synovial joints

Question 20

Which of the following best explains why interstitial growth is important in bone development?

Accepted Answer

It allows bones to increase in length by expanding cartilage within the growth plate.

Skeletal and Muscular System: Study Guide

Study Guide - Practice Questions

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