Synaptic Transmission Flashcards
What is the neuromuscular junction generally referring to?
Somatic motor pathway.
Nicotinic AChRs mediate _____ Synaptic transmission.
Fast.
Autonomic output Innervates targets via a chain of 2 neurons.
In the example synapses of autonomic ganglia what are those two neurons and what do they do?
- Preganglionic neurons release ACh
- Postganglionic neurons which have the Nicotinic receptors that the ACh bind to.
Define neuromuscular junction.
The large synapse between a somatic motor neuron and a skeletal muscle fiber.
Test:
Test:
Define what an end plate is.
The region of the synapse in the muscle fiber that’s shaped like a saucer. (Post synaptic part of the neuromuscular junction)
What does this action potential look different compared to regular action potentials?
Because these action potentials are happening right by the somatic motor neuron. The stimulation of this neuron causes a depolarizing end plate potential.(graded potential)
That end plate potential is caused by the ACh that is realized by the neuron into the skeletal muscle. As ACh opens a ligand-gated ion channel that is a non-selective monocolvalent cation channel. (Meaning it allows both Na+ and K+ through it)
But the driving force of Na+ is stronger then K+ so the result is a depolarization as seen in the picture.)
YOU ONLY SEE THIS BY THE END LATE, at 2 mm away you get a regular action potential.
Explain the green arrows.
These happen spontaneously from release of ACh from one or two synaptic vesicles.
What type of potential is end plate potential? Graded of Action?
Graded potential.
Skeletal muscles are _______ cells.
Excitable.
Define what the safety factor is.
Refers to the amount that the end plate potential exceeds the threshold for action potential initiation.
The neuromuscular junction has a high safety factor. What does this mean?
This means that each action potential in a somatic motor neuron will result in an action potential in the skeletal muscle fiber.
What does the localization of voltage gated Na+ channels contribute to end plate potential?
Contributes to the reliability of action potential initiation by an end plate potential.
When is the magic motor on fires and action potential what happens? (Specifically about muscle fibers)
What is Myasthenia gravis?
Explain what’s going on in myasthenia gravis.(science)
What is the treatment for myasthenia gravis?
CNS synaptic transmission is quite different from synaptic transmission at the neuromuscular junction. Explain the difference. (3)
Somatic motor neuron rules for each bullet point:
1. Only 1 input.
2. Only excitatory
3. The postsynaptic potential of a motor neuron is always strong enough to elicit an action potential. This is not true at all for the central nervous system.
Post synaptic potentials can act together, what is this called?
Define spatial summation and what makes it different from temporal summation.
What defines the different aspects of neurotransmission?
1. For if it’s fast or slow.
2. For if it’s excitatory or inhibitory.
Pin active potentials can be either excitatory or inhibitory, depending on the type of receptor. For the 4 ions we need to know, what does each ion channel opening due to the neuron? Excitatory or inhibitory affect?
What is the main excitatory neurotransmitter in the central nervous system? What are the two receptors for it?
Glutamate.
What is the main inhibitory neurotransmitter in the central nervous system?
Fast neurotransmission.
How do we often refer to neurotransmitters that involve slow neurotransmission?
Neuromodulators.
Notice how there isn’t a direct target it’s more like a diffuse thing .
What do drugs that target serotonin and epinephrine reuptake to treat depression do?
Categorize these into fast and slow:
Glutamate, norepinephrine, serotonin, GABA Histamine, ACh working through nicotinicAChRs, ACh working through muscarinic AChRs, dopamine
