The so-called "pseudo-H zone" in a sarcomere is:: (A) M line plus lighter areas on its either side, (B) Not seen normally in a sarcomere, (C) Seen only in an extremely contracted state of a muscle, (D) Disappearance of H band during contraction
Answer is A. At the very center of the sarcomere, there is H-zone (the gap between the ends of the thin filaments). The dark line at the center of the H-zone is called M-line. This dark M-line plus the light areas on either side constitutes the pseudo-H zone.