Author Question: Muscle contractions occur when there is a decreased: a. distance between Z lines. b. A band ... (Read 105 times)

sheilaspns · **on:** Jun 25, 2018

Muscle contractions occur when there is a decreased:

a. distance between Z lines.
b. A band length.
c. Z line length.
d. H zone distance.

Question 2

The molecule that aids in bonding of the troponin complex to actin and tropomyosin is troponin:

a. C.
b. I.
c. T.
d. M.

kingdude89 · **Reply #1 on:** Jun 25, 2018

Answer to Question 1

ANS: A
Anatomically, contraction occurs when the sarcomere shortens, so adjacent Z lines move closer together. Such a contraction does not occur in relationship to a decrease in A band or Z line length or a decrease in H zone distance.

Answer to Question 2

ANS: C
Troponin T aids in the binding of the troponin complex to actin and tropomyosin. Troponin C contains binding sites for the calcium ions involved in contraction. Troponin I inhibits the ATPase of actomyosin. Troponin M is not a substance.