Muscle Contraction Flashcards
What are the steps of the muscle contraction process?
1) Depolarisation and calcium ion release
2) Actin and myosin cross-bridge formation
3) Sliding mechanism of actin and myosin filaments
4) Sarcomere shortening (muscle contraction)
Where is the action potential initiated in Depolarization?
The motor neuron
Where is acetylcholine released?
Synaptic cleft
Where does depolarization occur?
Along the sarcolemma and through the muscle fibers via T tubules
What releases the stores of calcium ions?
Sarcoplasmic reticulum
What are the binding sites for the myosin heads covered by?
Troponin and tropomyosin
What causes the exposing of the binding sites for the myosin heads?
Calcium ions binding to troponin
What forms a cross-bridge?
Myosin heads with actin filaments
What process breaks the cross-bridge between actin and myosin?
ATP binding to the myosin head
What causes myosin head to move towards next actin binding site?
ATP hydrolysis
What causes the sliding mechanism?
The reorientation of the myosin head into their original conformation
Where are actin filaments anchored?
Z lines
