Anatomy 9b Muscle Contractions

Front

What is the role of myosin in muscle contraction?

Back

Myosin is a protein that forms thick filaments in muscle fibers and is responsible for pulling on actin filaments to cause muscle contraction.

Front

What is the synaptic cleft?

Back

The synaptic cleft is the gap between the motor neuron and the muscle fiber at the neuromuscular junction, where neurotransmitters are released to stimulate muscle contraction.

Front

Define a sarcomere.

Back

A sarcomere is the contractile unit of a muscle fiber, defined as the segment between two Z lines.

Front

What is attached to the Z line in muscle fibers?

Back

Actin filaments are attached to the Z line in muscle fibers.

Front

How does myosin contribute to muscle contraction?

Back

Myosin pulls on actin filaments, causing the muscle to contract.

Front

What are thick filaments primarily composed of?

Back

Thick filaments are primarily composed of myosin proteins.

Front

What is the function of the sarcoplasmic reticulum?

Back

The sarcoplasmic reticulum stores calcium ions and releases them during muscle contraction.

Front

What is the role of actin in muscle contraction?

Back

Actin is a protein that forms thin filaments and interacts with myosin to facilitate muscle contraction.

Front

What is the function of T Tubules in muscle fibers?

Back

T Tubules are extensions of the sarcolemma that help transmit the action potential into the muscle fiber, triggering calcium release.

Front

What is the significance of the Z line in a sarcomere?

Back

The Z line serves as the boundary of a sarcomere and anchors the actin filaments.