chemical brain Flashcards
describe the process of neurotransmission
ap opens calcium ion channels in presynaptic
calcium in and bind with calmodulin
cause synaptic vesicles to bind to presynaptic membrane
neurotransmitter released into synaptic cleft via exocytosis
move down concentration gradient to post synaptic
bind to specific proteinionotropic receptors via lock and key
depolarisation or hyperpolarisation of post
depolarisation is caused by
influx of sodium
hyperpolarisation caused by
influx of chloride or efflux of potassium
how are neurotransmitters synthesised or stored
synthesised in soma/axon terminal
transport via microtubules to axon terminal
store in synaptic vesicles
how are neurotransmitters deactivated?
diffusion away from cleft
degradation - enzymes break down and recycled to pre
reuptake - neurotrans bind to transporters on pre
autoreceptor binding - bind to receptors on pre and prevent further release
glial uptake - take up by glial and returned to axon terminal
what is an EPSP
excitatory postsynaptic potential
small graded positive shift in charge caused by sodium influx
what is an IPSP?
inhibitory postsynaptic potential
graded negative shift in charge caused by potassium efflux of chloride influx
useful to stabilise responses ie prevent epilepsy
what is temporal summation?
graded potentials occuring at approx. same time to reach threshold value
neuron has lots of connections
what is spacial summation?
graded potentials occuring at approx. same place
where do graded potentials build up
axon hillock
who discovered neurotransmitters
otto loewi (1921)
describe otto loewi’s experiment
two frog hearts in chambers connected to eachother
heart one stimulated
electrical stimulation cause stimulation of second heart
first heart release chemical (acetylcholine) into surrounding fluid
