nervous tissue Flashcards
resting potential
neurone that isnt transmitting an action potential and is at rest
when neurone at rest it is negativelly chargd inside
speed of action potential
faster when axon diameter is bigger
nerve impulse travelles quicker if neurone is myelinated
fewer synapses to cross = quicker
what are neurones
cells that recieve and facilitate nerve impulses across their membrane and onto the next neurone
what consists in a neurone
dendrites, cell body (soma), nucleus, axon terminals, node of ranvier, myelin sheath, shwan cells, axon
nerve impulse
ionic imbalances that travel from one neurone to another
what deos resting potential of -70mV mean
the sodium-potassium channels are pumping sodium to the outside of the cell and potassium to the inside of cell
what is depolarization
when the positive sodium atoms flood into the call causing the restng potential to decrease
what is repolarization
at +40mV, the na channels close and the k channels open causing the charge of the cell to go back down
how does a signal get from one neurone to the other
action potential cannot just cross the synapse, so as it reaches the end of neurone na channels get opened, this makes vesicles containing neurotransmitters to fuse with the presynaptic membrane and crosss the synapse where they bind to receptors in the postsynaptic membrane.
how do we stop the signal
either they get reabsorbed into the neurone or an enzyme breaks them down
what do neurotransmitters cause after crossing the synapse
initiate action potential in the other neurone, as presynaptic neurone ends in a swelling called ‘synaptic bulb’ and contains many mitochondria as atp is needed
where are the neurotransmitters stored before releases across the synapse
in teporary vesicles in the synaptic bulb
