What causes the contraction of living muscle tissue?
The contraction of a striated muscle fiber occurs as the sarcomeres, linearly arranged within myofibrils, shorten as myosin heads pull on the actin filaments. A myofibril is composed of many sarcomeres running along its length; thus, myofibrils and muscle cells contract as the sarcomeres contract. The muscle contraction cycle is triggered by calcium ions binding … Read more