Which statement describes white muscle?

Which statement describes white muscle?

• A. White muscle is mostly fast fibers, pale, limited blood supply, fast contractions, fatigues rapidly.
• B. Red muscle is mostly fast fibers, pale.
• C. White muscle is found only in heart.
• D. White muscle has a rich blood supply.

Answer: (A)

White muscle is made up mostly of fast-twitch glycolytic fibers. These fibers contract quickly and forcefully but fatigue rapidly because they rely on anaerobic metabolism and have fewer mitochondria and less myoglobin. The pale appearance reflects the low myoglobin content and sparser blood supply compared with red, slow-twitch fibers. This combination—primarily fast fibers, pale color, and limited blood supply—produces rapid, powerful contractions that tire quickly.

White muscle is made up mostly of fast-twitch glycolytic fibers. These fibers contract quickly and forcefully but fatigue rapidly because they rely on anaerobic metabolism and have fewer mitochondria and less myoglobin. The pale appearance reflects the low myoglobin content and sparser blood supply compared with red, slow-twitch fibers. This combination—primarily fast fibers, pale color, and limited blood supply—produces rapid, powerful contractions that tire quickly.