A&P - Chapter 19 (Part 2) Flashcards
Presynaptic
Before the neuron
Postsynaptic
After the neuron
What is the journey of a neuron? (6)
- Presynaptic neuron
- Synapse
- Postsynaptic neuron
- Neuron
- Neuromuscular/glandular synapse
- Effector
What 3 structures do synapses consist of?
- Synaptic knob
- Synaptic cleft
- Plasma membrane of postsynaptic neuron
What does a synapse ensure?
That there is only one way transmission of a nerve impulse
Synaptic knob
Tiny bulge at the end of a terminal branch of a presynaptic neurons axons that contains vesicle full of neurotransmitters
Synaptic cleft
Microscopic space between a synaptic knob and the plasma membrane of postsynaptic neuron (at the dendrites)
What do plasma membranes of the postsynaptic neuron contain?
Receptors for neurotransmitters
What do action potential cause when they reach the synaptic knob?
Ca to quickly diffuse into the knob
What does increase of Ca trigger?
The release of neurotransmitters via exocytosis
Where do neurotransmitters diffuse?
Across the synaptic cleft and bind to the receptors in the membrane of the postsynaptic neuron
What do neurotransmitters cause?
Ion channels to open
What do the opening of ion channels cause?
A postsynaptic potential
How long is the neurotransmitter action in the synaptic cleft?
Short term
When is the neurotransmitter action ended by? (3)
- Reabsorption back into synaptic knob
- Inactivation by special enzymes
- Diffused and taken up by nearby glia
