14 Questions
What is the name of the small gap that separates the motor neuron's axon terminal from the muscle fiber?
Synaptic cleft
What promotes the fusion of synaptic vesicles containing acetylcholine with the motor neuron's cell membrane?
Influx of calcium
What does acetylcholine bind to on the muscle fiber's membrane at the synaptic cleft?
Receptors on the motor end plate
What is generated in the muscle fiber due to the binding of acetylcholine?
End plate potential (EPP)
What triggers an action potential that spreads across the muscle fiber's membrane and into its interior?
Sufficient magnitude of EPP
What initiates a series of events that expose binding sites on actin filaments during muscle contraction?
Calcium ions binding to troponin
What leads to the relaxation of the muscle fiber?
Active pumping of calcium back into SR
What is the temporary change in the permeability of the muscle cell membrane to sodium ions caused by?
Acetylcholine binding to receptors on the motor end plate
What is the local depolarization of the motor end plate known as?
End Plate Potential (EPP)
What triggers the release of acetylcholine into the synaptic cleft from the synaptic vesicles?
Influx of calcium into the motor neuron's axon terminal
What is responsible for triggering the opening of voltage-gated calcium channels at the axon terminal of the motor neuron?
Action potential reaching the axon terminal
What triggers the release of calcium ions from the sarcoplasmic reticulum (SR) in a muscle cell?
Action potential in the T-tubules
What leads to the termination of the signal for muscle contraction?
Acetylcholine breakdown by acetylcholinesterase
What directly initiates a series of events that expose binding sites on actin filaments during muscle contraction?
Calcium ions binding to troponin
Study Notes
Muscle Contraction and Neurotransmission
- The small gap that separates the motor neuron's axon terminal from the muscle fiber is called the synaptic cleft.
- The fusion of synaptic vesicles containing acetylcholine with the motor neuron's cell membrane is promoted by voltage-gated calcium channels.
- Acetylcholine binds to nicotinic receptors on the muscle fiber's membrane at the synaptic cleft.
- The binding of acetylcholine generates an end-plate potential in the muscle fiber.
- The end-plate potential triggers an action potential that spreads across the muscle fiber's membrane and into its interior.
- The action potential initiates a series of events that expose binding sites on actin filaments during muscle contraction.
- The binding of calcium ions to troponin and tropomyosin leads to the exposure of binding sites on actin filaments.
- The relaxation of the muscle fiber is led by the removal of calcium ions from the sarcoplasmic reticulum (SR) and the muscle cell membrane.
- The temporary change in the permeability of the muscle cell membrane to sodium ions is caused by the action potential.
- The local depolarization of the motor end plate is known as an end-plate potential.
- The release of acetylcholine into the synaptic cleft from the synaptic vesicles is triggered by the opening of voltage-gated calcium channels.
- The opening of voltage-gated calcium channels at the axon terminal of the motor neuron is responsible for triggering the release of calcium ions.
- The release of calcium ions from the sarcoplasmic reticulum (SR) in a muscle cell is triggered by the action potential.
- The termination of the signal for muscle contraction is led by the breakdown of acetylcholine by acetylcholinesterase.
- The binding of calcium ions to troponin and tropomyosin directly initiates a series of events that expose binding sites on actin filaments during muscle contraction.
Learn about the neuromuscular junction and how action potentials in the motor neuron lead to muscle contraction. Understand the role of the motor neuron's axon terminal, the synaptic cleft, and the motor end plate in this process.
Make Your Own Quizzes and Flashcards
Convert your notes into interactive study material.
Get started for free
