Dr. Chirwa Flashcards
Presynaptic Mechanisms
Two types of presynaptic Mechanisms?
electrical and chemical
Electrical synapse
the movement of electrical current jumping from gap junction to gap junction.
Chemical synapse
The movement of neurotransmitters from one neuron to another
Post synaptic neurons
Have a slight delay
contains electrical vesicles in the presynaptic neuron
chemical synapse
Why does chemical synapse take much longer than electrical synapse?
because NT on chemical synapse to to line up with receptors of the post synaptic neuron, then release the presynaptic NT from the synaptic vesicle.
Synaptic vesicle
stores NT in vesicles in the presynaptic neuron in chemical synapse.
2 millisecond delay
is seen with chemical delay occurs slowly due to neurons aligning releasing and binding of NT
1 millisecond delay
seen with electrical delay which occurs quickly through gap junctions
Synapsin
anchors group of NT vesicles together
Docking
NT being free and going close to the plasmalemma
What must occur before NT vesicles release NTs docked on the plasmalemma?
Calcium must enter the neuron through calcium channels.
Clathrin
A protein that reclaims back old NT cleaving inward.
Dyanamine protein
takes the neck of the Clathrin vesicle so it can be released
At rest the presynaptic terminal is negative or positive.
it is negative until an AP occurs the presynaptic terminal becomes more positive (depolarize)
When does depolarization occur?
When calcium enter the neuron through calcium channels
What type of cells pick up calcium ions in the synaptic cleft?
glial cells