Lesson 7- Nerve Signals

Question 1

resting potential

Answer 1

net positive charge on the outside and net negative charge on inside. the potential difference across membrane is -70mV (ready to go)

Question 2

depolarization

Answer 2

upon stimulation, ligand-gated na channels open up and na flows into the membrane via facilitated diffusion

Question 3

action potential

Answer 3

potential difference changes to +30/40 mV. moves down neuron in wave-like way and triggers opening of na voltage-gated channels

Question 4

repolarization

Answer 4

sopi pumps use atp to move na out of cell and k into cell and resets to resting potential with net positive outside and difference of -70mV

Question 5

refactory period

Answer 5

resting potential needs to be re-established before firing again (1-10ms), ensures that signals goes one way

Question 6

axon hillock

Answer 6

determines whether or not a signal will travel with a threshold level of -55mV (over goes through). area is loaded with voltage gated na channels

Question 7

synaptic transmission

Answer 7

spaces between neurons or effectors. neurotransmitters are used to move impulses across. axon terminal contains vessels that hold not, stimulation releases not and it diffuses across to initiate impule in postsynaptic neurons

Question 8

electric sunapses

Answer 8

rare (heart), currtent flows instantly, pre and post synaptic cells are in direct contact

Question 9

chemical synapses

Answer 9

majority of synapses, delays transmission, diffusion, and binding, allows neurons to receive a lot of input at the same time. action potential reaches axon terminal, ca gates open and flow into cytosol, triggers protein in synaptic vesicles to fuse with cell membrane, nt is released through exocytosis and bind to postsynaptic receptor opening ion channels for ap to continue