CSCS CSCS: Structure & Function of Body System 4 — Questions and Answers
Question 1: During the Valsalva maneuver, intra-abdominal pressure increases primarily to:
- Increase heart rate for greater cardiac output
- Reduce oxygen demand during heavy lifting
- Stabilize the spine and trunk during maximal lifts (Correct answer)
- Decrease venous return to the heart
Correct answer: Stabilize the spine and trunk during maximal lifts
The Valsalva maneuver increases intra-abdominal and intrathoracic pressure, creating a rigid core that supports the spine against compressive forces during heavy lifts.
Question 2: Which proprioceptor is located within the muscle belly and detects changes in muscle length?
- Golgi tendon organ
- Pacinian corpuscle
- Ruffini ending
- Muscle spindle (Correct answer)
Correct answer: Muscle spindle
Muscle spindles (intrafusal fibers) are length-sensitive mechanoreceptors embedded in the muscle belly that detect stretch and mediate the myotatic (stretch) reflex.
Question 3: What percentage of cardiac output does the heart receive at rest?
- 1–2%
- 4–5% (Correct answer)
- 10–12%
- 20–25%
Correct answer: 4–5%
The coronary circulation receives approximately 4–5% of total cardiac output at rest to supply the myocardium with oxygen and nutrients.
Question 4: Which of the following bones is classified as a sesamoid bone?
- Calcaneus
- Scaphoid
- Patella (Correct answer)
- Hamate
Correct answer: Patella
The patella is the largest sesamoid bone in the body, embedded within the quadriceps tendon to improve mechanical advantage of the extensor mechanism.
Question 5: The stretch-shortening cycle (SSC) is most closely associated with which type of muscle action sequence?
- Concentric followed by isometric
- Eccentric followed by concentric (Correct answer)
- Isometric followed by concentric
- Concentric followed by eccentric
Correct answer: Eccentric followed by concentric
The SSC involves a rapid eccentric (lengthening) phase immediately followed by a concentric (shortening) phase, enhancing force production through elastic energy storage and neural potentiation.
Question 6: Which blood vessel carries deoxygenated blood from the right ventricle to the lungs?
- Pulmonary vein
- Pulmonary artery (Correct answer)
- Aorta
- Superior vena cava
Correct answer: Pulmonary artery
The pulmonary artery (and its branches) carries deoxygenated blood from the right ventricle to the lungs for gas exchange — the only artery in the body that carries deoxygenated blood.
Question 7: The quadriceps femoris group performs which primary joint action at the knee?
- Knee flexion
- Hip abduction
- Knee extension (Correct answer)
- Hip external rotation
Correct answer: Knee extension
The four muscles of the quadriceps femoris (rectus femoris, vastus lateralis, vastus medialis, vastus intermedius) converge at the patellar tendon and extend the knee.
CSCS CSCS: Structure & Function of Body System 4
During the Valsalva maneuver, intra-abdominal pressure increases primarily to: