NM - Excitation-Contraction Coupling (ECC)

Basic contractile unit of muscle present in the myofibril

Myofibril

Muscle Fascicle

Muscle Fiber

Actin and Myosin

Troponin and Tropomyosin

Acetyl Choline and Titin

Calcium and Sodium

Troponin and tropomyosin both block calcium from entering the muscle cell.

Troponin helps move tropomyosin to uncover binding sites on actin when calcium is present.

Tropomyosin directly causes muscle contraction by binding to myosin.

Troponin and tropomyosin make muscles contract without needing calcium.

The breakdown of ATP molecules.

The arrival of an electrical signal (action potential) at the muscle fiber.

The binding of myosin to actin.

The movement of tropomyosin away from actin.

Binding of neurotransmitters opens sodium channels, leading to depolarization of the postsynaptic membrane.

Neurotransmitters directly bind to voltage-gated calcium channels, causing an action potential.

The reuptake of neurotransmitters into the presynaptic neuron triggers action potential generation.

Neurotransmitters close potassium channels, causing hyperpolarization and action potential generation.

Neuromuscular junction

Dendrite

Synapse

Axon terminal

Excitation-contraction coupling

Muscle relaxation

Neurotransmitter release

Action potential generation