Neuromuscular Junction

Front

What is the synaptic cleft?

Back

The synaptic cleft is the small gap between the axon terminal of a motor neuron and the sarcolemma of a muscle fiber, where neurotransmitters are released.

Front

What are synaptic vesicles?

Back

Synaptic vesicles are small membrane-bound sacs in the axon terminal that contain neurotransmitters, such as acetylcholine, which are released into the synaptic cleft.

Front

What is the role of acetylcholine in the neuromuscular junction?

Back

Acetylcholine is a neurotransmitter that binds to receptors on the sarcolemma, triggering muscle contraction.

Front

Define the term 'sarcolemma'.

Back

The sarcolemma is the plasma membrane of a muscle fiber that surrounds the muscle cell.

Front

What is a motor unit?

Back

A motor unit consists of a motor neuron and all the muscle fibers it innervates, working together to produce muscle contractions.

Front

What is a sarcomere?

Back

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

Front

What happens during the process of muscle contraction?

Back

During muscle contraction, acetylcholine is released into the synaptic cleft, binds to receptors on the sarcolemma, and initiates a series of events that lead to the shortening of sarcomeres.

Front

What is the function of calcium ions in muscle contraction?

Back

Calcium ions are released from the sarcoplasmic reticulum and bind to troponin, causing a conformational change that allows myosin to bind to actin, leading to muscle contraction.

Front

What is the neuromuscular junction?

Back

The neuromuscular junction is the synapse or junction between a motor neuron and a muscle fiber, where nerve impulses are transmitted to initiate muscle contraction.

Front

What are acetylcholine receptors?

Back

Acetylcholine receptors are proteins located on the sarcolemma that bind acetylcholine, leading to depolarization of the muscle fiber.