Which structure is the contractile subunit of the myofibril?
A) Sarcoplasmic reticulum
B) Actin
C) Motor endplate
D) Sarcomere

Question

Quizplus · Accepted Answer

The sarcomere is the contractile subunit of the myofibril, consisting of overlapping thick and thin filaments made up of myosin and actin, respectively. The sarcoplasmic reticulum is the organelle responsible for storing and releasing calcium ions during muscle contraction, while the motor endplate is the specialized region of the neuromuscular junction where the nerve fiber and muscle fiber meet.

Which Structure Is the Contractile Subunit of the Myofibril