Question

The muscles of domesticated chickens represent the differences between fast-twitch and slow-twitch muscle fiber well. Chickens do not fly long distances but rather have bursts of flight so they can quickly move away from danger. The muscles for flight (breast muscles) are lighter in color than the muscles for walking and running (leg muscles). Which types of muscle fibers are found in each area?

A) Fast-twitch in breast muscles, slow-twitch in leg muscles
B) Slow-twitch in breast muscles, fast-twitch in leg muscles
C) Fast-twitch in both breast and leg muscles
D) Slow-twitch in both breast and leg muscles

Answer 1

Domesticated chickens have breast muscles composed of fast-twitch muscle fibers for short bursts of flight and leg muscles composed of slow-twitch muscle fibers for endurance activities like walking and running, making the correct answer A) Fast-twitch in breast muscles, slow-twitch in leg muscles.

Step-by-step explanation:

The question pertains to the different types of muscle fibers found in domesticated chickens' breast and leg muscles. Domesticated chickens tend to have short bursts of flight, indicating that their breast muscles, which are responsible for flight, would be composed primarily of fast-twitch muscle fibers. These fibers can contract rapidly and powerfully, but they fatigue quickly, making them suitable for the short bursts of energy needed in flight. On the other hand, their leg muscles are darker and are used for activities like walking and running, which require endurance. This suggests that their leg muscles would have a higher proportion of slow-twitch muscle fibers, which are designed for long-term contraction and activities requiring stamina rather than short, explosive movements. Therefore, the answer to the question is A) Fast-twitch in breast muscles, slow-twitch in leg muscles.