Bio – week six (neurochemistry) – Flashcards

sends the message

receive the message

vesicles containing neurotransmitters are dumped into the synapse - this has an effect on the post-synaptic cell - inhibitory decreases the likelihood of post synaptic cell firing, and excitatory increases the likelihood of post-synaptic cell firing

neurotransmitters

can change the signal from excitation to inhibition have flexibility about the signal given off can be affected by other chemicals in the body can allow selectivity - can prevent certain receptive cells many weak signals can add up to make a response

vesicles full of neurotransmitters are held in the axon terminal and when the action potential reaches the end of the axon it triggers calcium channels to open - influx of calcium ions in axon terminal = vesicles will merge with the membrane - releases neurotransmitters into the synaptic cleft

the neurotransmitter will bind to a complementary receptor site on the post-synaptic membrane (lock and key - some require another chemical in order to bind) binding of the neurotransmitter causes a shape change in the ligand/transmitter gated ion - open/closes the ion channel = affects the flow of ions through it if it allows negative ions in = further hyper-polarises (away from action potential) if it allows positive ions in = depolarises the cell towards the excitation threshold happens at many different places and IT IS THE SUMMATION OF -VE/+VE THAT LEADS TO AN ACTION POTENTIAL

multiple pre-synaptic neurons releasing neurotransmitters onto the same post-synaptic membrane - if they're close enough in time

multiple pre-synaptic neurons releasing neurotransmitters onto the same post-synaptic membrane - if they're close enough spatially + in time

released at the junction between nerves and muscles - makes muscles contract

involved in the mechanism of sleep, mood and arousal

inhibitory transmitter of CNS

excitatory transmitter in the brain crucial in learning + memory

helps control arousal level influences wakefulness, learning and memory

influences movement, emotion and motivation

binds directly to the ion channel can cause change in shape of channel - affects ion flow can be positive or negative

binds to another protein on the cell membrane causes changes inside the cell - affects ion channels

enhances the neurotransmitters effect: mimics the neurotransmitter increases release of neurotransmitter counteracts clean up enzymes blocks the re-uptake

impedes the neurotransmitters effect: blocks the release of neurotransmitters can block them from binding

at synthesis, release, the receptor, turnover or re-uptake

GABA normally binds to receptors and allows in some -ve ions - reducing the cells likelihood to fire - alcohol will also bind and keep the channels open for longer - more inhibition

indirect affect on GABA neurons - less inhibition of dopamine neurons = more dopamine is released = more firing in those cells - these cells are linked in a reward circuit which is normally inhibited by GABA cells but cannabis stops this inhibition

layer of tightly joined cells that surround the blood vessels in the brain - large molecules can not get through the tight junctions in the capillary wall - acts as a filter - stops most things from getting through

it can't cross the blood brain barrier but l-dopa can and then a chemical reaction can convert this into dopamine