Muscles and Movement: Topic 11.2

Question 1

Outline the structure of skeletal muscle.

Answer 1

Muscle; muscle bundle/fascicle; muscle fiber; myofibril; sarcomere

Question 2

Explain the process of muscle contraction.

Answer 2

Muscle action potential is propagated through the t-tubules causing ca channels to open on the sarcoplasmic reticulum release calcium ions, ca ions bind to troponin on actin filaments causing it to change shape which moves the tropomyosin and exposes the myosin binding sites on the actin, enzymes hydrolyze ATP providing the energy to change the shape of the myosin heads so they swivel outwards and bind to actin filaments (cross bridge), myosin heads release adp and move again swiveling back towards the center and pulling the actin in wards (power stroke), the process continues as long as there is ample ATP and calcium in the body