Muscle Contraction and Relaxation

Flashcards that cover key vocabulary and concepts related to muscle contraction and relaxation.

Cross Bridge

The temporary connection formed when myosin heads attach to actin during muscle contraction.

ATP

Adenosine triphosphate, the energy currency of the cell, required for cross bridge detachment.

Cocking of the Myosin Head

The process in which myosin hydrolyzes ATP to ADP and P, allowing the myosin head to return to a high-energy position.

Calcium Ions (Ca²⁺)

Ions that, when released from the sarcoplasmic reticulum, bind to troponin, allowing muscle contraction to occur.

Tropomyosin

A protein that blocks the myosin binding sites on actin when the muscle is relaxed.

E-C Coupling

Excitation-contraction coupling, the process by which action potentials lead to muscle contraction.

Sarcolemma

The plasma membrane of a muscle cell, involved in transmitting action potentials.

Terminal Cisternae

The enlarged ends of the sarcoplasmic reticulum where calcium ions are stored and released.

Active Transport

The process of moving calcium ions back into the sarcoplasmic reticulum, which is essential for muscle relaxation.

Power Stroke

The movement that occurs when the myosin head pivots and pulls the actin filament, shortening the muscle.