_______ are the Basic Units of Muscle Contraction

Question

_______ are the basic units of muscle contraction.
A) Myofibrils
B) Sarcomeres
C) Z lines
D) Muscle fibers

Accepted Answer

Sarcomeres are the basic units of muscle contraction. They are tiny contractile units within a muscle fiber made up of overlapping actin (thin) and myosin (thick) filaments. When muscle fibers receive a signal to contract, the sarcomeres shorten, causing the entire muscle to contract. Myofibrils are chains of sarcomeres linked end to end and muscle fibers are composed of many myofibrils. Z lines are the boundaries of sarcomeres.