Physiology 3

more for Na then K these gates are always open.

needs a stimulus to open them up,

opens up with the right membrane potential ions change

Chemicals like neurotransmittor and or hormones

streching or deforming the shape of the cell to let stuff in. Ex. pressure such as touch (sensory).

3 Na K or Ca

when it attaches to a vesicle it lets it do a exocytosis of the neurotransmitter. When the voltage gates are open it makes the cell more permability.

whenever you are transfering a ion across the membrane you are generating a current across the cell. doesnt matter what ion as long as they going across the membrane. the current causes a change in the membrane potential

excites the post synaptic membrane. postive charges coming in like ACh. sodium moves in potassium moves out because of the ACh exciting it causing membrane potential to be more positive.The postive area moves down because of diffusion it moves down but fades after a while but if theres another puff it adds to that charge.

GABA it inhibits so K moves in increase of Cl- making the membrane potential negative making it more likely to have action potential. you would want this when you sleep so that you dont move around.

1st stimulus then needs another stimulous to get enough action potential. they are trying to reach the axon hillock (initiation zone) because the first one just isnt enough

2 or more axons SIMULTANIOUSLY releasing the stimulous so that its a big bang making it reach the axon hillock and create action potential

enzymes break down the neurotransmitter to stop the reaction, they always end with -ase

..of neurotransmitter so that it stops the reaction. and it does endocytosis and gets sucked up back into the cell ex. epinephrine seratonin dopamine

inhibits the enzymes from breaking down the neurotransmitter so its more likely to be absorbed. Ex. prozac Seratonin reuptake inhibitor SSRI is a specific inhibitor so there is less side affects then a general one.

serotonin is release helping make more Ca gates open up so more Ca can come in and more neurotransmitter is released more exocytosis.

GABA is released into the presynaptic structure which decrease the amount of neurotransmitter that is released because less Ca can come in the gaba blocks the voltage gated Ca gates.

a brief transiant change in the membrane potential in response to a stimulous.

a stimoulous causes a change in the permability of a membrane Ex. chemical mechanical, heat light or electrical