neuronal communication SLOP Flashcards
What happens when CO2 levels in blood is too high?
pH lowers = chemoreceptors detect and increase frequency of impulse to mudulla oblongata which increases frequency of impulses to SAN via sympathetic nervous system = increase wave of excitations produced by SAN which increases blood flow= increase CO2 removal
what happens when blood pressure is too high?
pressure receptors detect this and increase frequency of impulses to the medulla oblongata. the parasympathetic NS sends impulse to SAN decreasing HR
what happens when blood pressure is too low?
pressure receptors detect this and increase frequency of impulses to the medulla oblongata. the parasympathetic NS sends impulse to SAN increasing HR
what is an ectotherm and give an example
take heat from surroundings to warm core body temp e.g. lizard
what are receptors
take in neurotransmitters to pass on message
how is resting potential maintained?
sodium and potassium pumps actively transport 3NA+ out and 2K+ IN the axon. Sodium gates are closed but K+ gates open allowing more K+ to move out axon = back to action potential
what is temporal summation
one presynaptic neurone releases neurotransmitters many times in short period
binding to what?
in cholinergic synapses what affect does acetylcholine molecules have
they bind to receptors on sodium ion channels, cause Na+ to diffuse rapidly down concentration gradient and generate Action P
function of acetylcholinesterase
break down acetylcholine into ethanoic acid and choline which stops it from continuously generating Action potentials
what ensures synapses are unidirectional?
vesicles only produced in pre-synaptic neurone, and receptors only found on post synaptic neurone
Cl-
how do inhibitory synapses work?
neurotransmitter from presynaptic neurone bind on Cl- channels on post -SN, opening them causing Cl- to move in (facilitated diffusion). This causes potassium channels to open and K+ diffuse out out post-SN making it more negative in the axon = more NA+ needed to generate Action P
in cholinergic synapses what does the arrival of action potential cause?
in the presynaptic neurone Ca2+ protein channels open and Ca2+ enter it by facilitated diffusion
*in cholinergic synapses what effect does influx of calcium ions have?
they bind to receptors on sodium ion channels, causing Na+ to diffuse rapidly down conc. gradient and generate Action P
MLP: the power of friendship
what is spatial summation?
different presynaptic synaptic bulbs that all contribute neurotransmitters to one post synaptic neurone
what is refractory period and why is it important
once Action P created, it’s period where Na+ inward movement prevented = ensures AP are unidirectional, and of limited number
