Muscle Microanatomy

Question 1

Myofibril: Contractile Portion in Muscle Fiber

Answer 1

There are hundreds to thousands of myofibrils in each skeletal muscle fiber

Along the length of a myofibril, there are repeating segments called sarcomeres

Question 2

Sarcomere

Answer 2

Basic functional unit of skeletal muscle
–contraction of sarcomere is what contracts the muscle

A sarcomere extends from Z disk to Z disk

There can be as many as 10,000 sarcomeres per myofibril

The center of the sarcomere is the M line

Question 3

Muscle Contraction

Answer 3

Sliding Filament Mechanism: the think and thick filament slide past each other