IAG_38.docx!!!!!!!!!!!!!!!! IAG_38.docx IAG_38.docx
OpenStax Biology 2e Instructor Answer Guide
Biology 2e
Unit 7: Animal Structure and Function
Chapter 38: The Musculoskeletal System
Visual Connection Questions
1. Which of the following statements about bone tissue is false?
b. Haversian canals contain blood vessels only.
2. Which of the following statements about muscle contraction is true?
b. The power stroke occurs when ADP and phosphate dissociate from the myosin head.
IAG_38.docx 4/20/2026, 2:15:29 PM IAG_38.docx
, IAG_38.docx!!!!!!!!!!!!!!!! IAG_38.docx IAG_38.docx
OpenStax Biology 2e Instructor Answer Guide
3. The deadly nerve gas Sarin irreversibly inhibits acetylcholinesterase. What effect would Sarin
have on muscle contraction?
In the presence of Sarin, acetycholine is not removed from the synapse, resulting in continuous
stimulation of the muscle plasma membrane. At first, muscle activity is intense and
uncontrolled, but the ion gradients dissipate, so electrical signals in the T-tubules are no longer
possible. The result is paralysis, leading to death by asphyxiation.
Review Questions
4. The forearm consists of the:
a. radius and ulna
5. The pectoral girdle consists of the:
c. clavicle and scapula
6. All of the following are groups of vertebrae except ________, which is a curvature.
d. pelvic
7. Which of these is a facial bone?
c. lacrimal
8. Which of the following is not true statement comparing exoskeletons and endoskeletons?
d. Exoskeletons provide less mechanical leverage.
IAG_38.docx 4/20/2026, 2:15:29 PM IAG_38.docx
OpenStax Biology 2e Instructor Answer Guide
Biology 2e
Unit 7: Animal Structure and Function
Chapter 38: The Musculoskeletal System
Visual Connection Questions
1. Which of the following statements about bone tissue is false?
b. Haversian canals contain blood vessels only.
2. Which of the following statements about muscle contraction is true?
b. The power stroke occurs when ADP and phosphate dissociate from the myosin head.
IAG_38.docx 4/20/2026, 2:15:29 PM IAG_38.docx
, IAG_38.docx!!!!!!!!!!!!!!!! IAG_38.docx IAG_38.docx
OpenStax Biology 2e Instructor Answer Guide
3. The deadly nerve gas Sarin irreversibly inhibits acetylcholinesterase. What effect would Sarin
have on muscle contraction?
In the presence of Sarin, acetycholine is not removed from the synapse, resulting in continuous
stimulation of the muscle plasma membrane. At first, muscle activity is intense and
uncontrolled, but the ion gradients dissipate, so electrical signals in the T-tubules are no longer
possible. The result is paralysis, leading to death by asphyxiation.
Review Questions
4. The forearm consists of the:
a. radius and ulna
5. The pectoral girdle consists of the:
c. clavicle and scapula
6. All of the following are groups of vertebrae except ________, which is a curvature.
d. pelvic
7. Which of these is a facial bone?
c. lacrimal
8. Which of the following is not true statement comparing exoskeletons and endoskeletons?
d. Exoskeletons provide less mechanical leverage.
IAG_38.docx 4/20/2026, 2:15:29 PM IAG_38.docx
