NMJ Transmission

Terms in this set (9)

Neuromuscular junction
An electrical-chemical-electrical link between motor nerves and muscles.
Neurotransmitter of the NMJ
Acetylcholine (ACh)
Quanta
Discrete units of acetylcholine packing into vesicles found in the presynaptic membrance. Each contain up to 10,000 molecules.
3 types of quanta stores
Primary/Immediately available store
Secondary/Mobilization store
Tertiary/Reserve store
Primary store
Quanta storage immediately available for release. Consists of approximately 1000 quanta located just beneath the presynaptic nerve terminal membrane.
Secondary store
Quanta storage that consists of approximately 10,000 quanta that can resupply the primary store after a few seconds.
Tertiary store
Quanta storage where >100,000 quanta exists far from the NMJ in the axon and cell body.
Voltage-gated Calcium channels (VGCCs)
Channels found within the presynaptic membrane that are activated by a nerve action potential, allowing an influx of calcium ions into the membrane. This process then releases acetylcholine quanta into the synapse.
Chemical-gated Sodium channels
Channels found within the postsynaptic membrane that are activated when acetylcholine bind to them. This allows sodium into the postsynaptic membrane, resulting in a local depolarization known as the end plate potential.
YOU MIGHT ALSO LIKE...
;