Which molecule prevents a muscle contraction from occurring when ...

[nelaaney]

Which molecule prevents a muscle contraction from occurring when the muscle is at rest?
 
  a. Calcium
  b. Troponin-tropomyosin
  c. Actin
  d. Myosin

Question 2

Which characteristic of a postural muscle is a result of having substantial amounts of type I mus-cle fibers?
 
  a. Resists fatigue
  b. Rapid response time
  c. Little contractibility
  d. Lacks a fascia lining

[wilsonbho]

Answer to Question 1

ANS: B
Contraction begins as the calcium ions combine with troponin, a reaction that overcomes the in-hibitory function of the troponin-tropomyosin system. Calcium, actin, and myosin all facilitate muscle contraction.

Answer to Question 2

ANS: A
Postural muscles have more type I fibers, allowing them the high resistance to fatigue that is nec-essary to maintain the same position for extended periods. The ocular muscles have more type II muscle fibers, allowing them to respond rapidly to visual changes.
Little contractibility or lacking a fascia lining is associated with type I muscle fibers.

[nelaaney]

Excellent

[Liddy]

Thanks for the timely response, appreciate it