Neurones; Communication between them (NB 020) Flashcards
Definition of Synapses ?
The site of contact between 2 neurons or 2 cells without protoplasmic continuity
Compare Spatial and Temporal summation in terms of :
-which is most common
- how they occur
-can both accure at same time ?
Compare Action potential and Postsynaptic potentials in terms of :
-effect on membrane negativity
- all or none law ?
- grading
-refractory periods ?
-summation
-propagation
-duration
How is the Postsynaptic response graded ?
What determines the resistance of the membrane Rm ?
Define Synaptic delay
time passed between arrival of the impulse at presynaptic terminal till excitation of postsynaptic neuron).
Why does Synaptic fatigue happen ?
due to depletion of the neurotransmitter vesicles.
Define Synaptic plasticity
change in synaptic transmission which may be increase (potentiation) or decrease (inhibition) for short or long term.
Define Convergence and mention it’s function
Define Divergence and mention it’s function
What happens at the Excitation field ?
all the neurons in the pool are excited by a single input.
What happens at the Discharge zone ?
the central neurons in the excitation field.
They receive large number of presynaptic terminals»_space; summation of many EPSP»_space; they can reach to firing level and discharge impulses.
What happens at the Facilitated zone (subliminal fringe) ?
the peripheral neurons in the excitation field, receive small number of presynaptic terminals»_space; summation of less EPSP»_space; they can not reach to firing level and discharge impulses but they are only facilitated.
Definition and mechanism of Fatigue in the neuironal pool ?
