Muscle Anatomy Review

Front

What is the neuromuscular junction?

Back

The region where a motor neuron comes in close contact with a muscle cell, allowing for communication between the nervous system and muscle fibers.

Front

What must happen first in muscle contraction?

Back

The action potential must reach the terminal branch of the axon.

Front

What is myosin?

Back

A myofibril that is a large bundle of proteins with contractile heads sticking out throughout the bundle, essential for muscle contraction.

Front

List the structures of a muscle from smallest to largest.

Back

myofibril, muscle fiber, fascicle, muscle.

Front

What is released from the sarcoplasmic reticulum during muscle contraction?

Back

Calcium.

Front

What role does acetylcholine play in muscle contraction?

Back

Acetylcholine is a neurotransmitter that transmits signals from the motor neuron to the muscle fiber, initiating contraction.

Front

Define muscle fiber.

Back

A muscle fiber is a single cylindrical cell that makes up a muscle, containing myofibrils and capable of contraction.

Front

What is the function of troponin in muscle contraction?

Back

Troponin is a protein that binds calcium ions and helps regulate muscle contraction by moving tropomyosin away from actin binding sites.

Front

What is the role of tropomyosin in muscle contraction?

Back

Tropomyosin is a protein that blocks the binding sites on actin filaments, preventing contraction until calcium binds to troponin.

Front

What is a sarcomere?

Back

The basic contractile unit of muscle tissue, defined as the segment between two Z lines.