PHYSIOLOGY
MUSCLE CONTRACTION
|
Question
[CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER]
|
|
|
True
|
|
|
False
|
|
|
Either A or B
|
|
|
None of the above
|
Detailed explanation-1: -For a muscle cell to contract, the sarcomere must shorten. However, thick and thin filaments-the components of sarcomeres-do not shorten. Instead, they slide by one another, causing the sarcomere to shorten while the filaments remain the same length.
Detailed explanation-2: -Answer and Explanation: The statement that is false is d. sarcomeres increase in length during contraction.
Detailed explanation-3: -The zone of overlap, in which thin filaments and thick filaments occupy the same area, increases as the thin filaments move inward. Remember that the actin and myosin filaments themselves do not change length, but instead slide past each other.
Detailed explanation-4: -During muscle contraction, the I band reduces in size as the overlap between the thick filaments and the thin filaments increases.