What transport process is utilized when ACh is released into the synaptic cleft?
How is the neurotransmitter acetylcholine removed from the synaptic cleft?
ACh diffuses across the synaptic cleft and binds to special receptors on the postsynaptic or the postjunctional membrane. First, ACh is removed by diffusion. Second, a substance in the synaptic cleft, called acetylcholinesterase (AChE), hydrolyzes or breaks down ACh.
What stimulates ACh release into the synaptic cleft of a neuromuscular junction quizlet?
What stimulates ACh release into the synaptic cleft of a neuromuscular junction? An action potential opens voltage-gated Ca2+ channels in the axon terminal.
What most directly causes synaptic vesicles to release acetylcholine into the synaptic cleft?
What happens if there is too much acetylcholine?
Excessive accumulation of acetylcholine (ACh) at the neuromuscular junctions and synapses causes symptoms of both muscarinic and nicotinic toxicity. These include cramps, increased salivation, lacrimation, muscular weakness, paralysis, muscular fasciculation, diarrhea, and blurry vision.
What triggers the release of acetylcholine from synaptic terminal?
Acetylcholine is stored in the terminal in small sacs, or vesicles. When an electrical impulse originating in the cell body travels down the axon to the terminal, it triggers the release of acetylcholine from the vesicles into the space between neurons (the synapse2) (Figure 5).
Is acetylcholine good or bad?
The bottom line. Acetylcholine is a neurotransmitter (chemical messenger) that plays a role in many key aspects of health, such as muscle movement, thinking, and many other brain functions.
What happens to the neuron when threshold stimulus is applied?
The threshold stimulus causes the membrane potential to become less negative (because a stimulus, no matter how small, causes a few sodium channels to open and allows some positively-charged sodium ions to diffuse in). Sodium ions rapidly diffuse inward, & depolarization occurs.
What opens first in response to a threshold stimulus?
What opens first in response to a threshold stimulus? Voltage-gated Na+ channels. The activation gates of voltage-gated Na+ channels open, and Na+ diffuses into the cytoplasm. Voltage-gated Na+ channels change shape, and their activation gates open.
Which part of motor neuron has lowest threshold?