48.4 synapses

Question 1

electrical synapses

Answer 1

let the electrical currents flow directly from one neuron to another

Question 2

how do neurotransmitters get sent across synapses?

Answer 2

1) action potential causes ca2+ to be released into dendrite
2) Ca2+ causes synaptic vesicles to fuse with terminal membrane and release neurotransmitter
3) neurotransmitter diffuses across synaptic cleft
4) it binds to a ligand gated ion channel and opens it
5) makes postsynaptic potential ```

Question 3

why do we need synapses?

Answer 3

information transfer better regulated

-the neurotransmitter can be regulated by a lot of things

Question 4

excitatory postsynaptic potentials

Answer 4

-brings closer to threshold
open channels that let Na+ and k+ diffuse
——-makes postsynaptic potential (change in ———membrane potential)

EXCITATORY

Question 5

inhibitory postsynaptic potentials

Answer 5

neurotransmitters bind to channels for K+ or Cl-
–hyper polarizes membrane
INHIBITS from threshold

Question 6

temporal summation

Answer 6

when one EPSP passes and

-another EPSP comes without time for first to return to resting

Question 7

spatial summation

Answer 7

EPSPs produced by different synapses tp the same post synaptic neuron

Question 8

why is only one EPSP not enough?

Answer 8

• post synaptic do not regenerate as they travel dow the cell
• and they get smaller, the further from the synapse (too far from the dendrite to the axon hillock-where AP is started)