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difference between afferent and efferent?
afferent- going toward CNS
efferent- going away from CNS
anatomy of a neuron?
dendrite- some- trigger zone- axon- synaptic knob
three fundamental properties of nerve cells?
excitability, conductivity, secretion
function of a neuron's trigger zone?
to sum up local graded potentials
function of ependymal?
CSF production and circulation
function of microglia?
function of oligeodendrocytes?
myelin sheathes for CNS
function of astrocytes?
- form scaffolding of CNS
- provide nutrients and growth factors to neurons
- take up wastes and neurotransmitters
- provide frame to direct nerve growth during development and new synapse formation after birth
- attach to capillaries to tighter them into a blood- brain barrier
a wrap of cell membrane around an axon that speeds transmission of an action potential and allows axons to regenerate
the action potentials have a skipping
describe nerve regeneration?
- old schwann cells produce growth factors that cause the axon to elongate
- new schwann cells wrap the axon as it grows
- can only occur in peripheral axons
steps leading to an action potential in a neuron?
- neurotransmitters bind to ligand-gated channels
- open channels allow ions to enter cell causing a change in resting membrane potential locally
- local changes are summed up at the trigger zone
- if the sum reaches threshold, voltage gated sodium channels open sequentially down the axon
types of neurotransmitters?
- amino acids
where are neurotransmitters made?
made in the soma of each neuron
how are they (neurotransmitters) released?
they are discharged from their transport vesicles at the synaptic knob by the interaction with calcium.
how are they (neurotransmitters) they degraded?
diffusion, re-uptake by presyanptic cell, uptake by astrocyte, enzyme degradation
what do they (neurotransmitters) do?
bind to receptors on the membrane of the post synaptic cell
three types of membrane channels involved in routine action potential?
- ligand- gated sodium channel
- voltage- gated sodium channel
- voltage- gated calcium channel
type of membrane protein involved in an adrenergic synapse?
a second messenger membrane protein
one post neuron receives input from three pre-synaptic neurons
three post, synaptic neurons receive input from pone pre-synaptic neuron