Chapter 2

Question 1

temporal summation

Answer 1

repeated stimuli over short period amount of time produced stronger response

Question 2

Excitatory postsynaptic potential

Answer 2

graded depolarization that decays over time and space

Question 3

spatial summation

Answer 3

sypnatic input from several locations can have cumulative effect when single stimuli did not

Question 4

Inhibitory synapes

Answer 4

interneuron in spinal cord sent an excitatory message to the flexor muscles and an inhibitory message to others

Question 5

increase number of action potential above spontaneous firing rate

Answer 5

EPSP

Question 6

When does IPSP act?

Answer 6

temporary hyperpolarization
- occurs when synaptic input opens the gates for positively charged K ions to leave the cell or negatively

Question 7

Explain chemical transmission at synapes

Answer 7

1. action potential arrival
   - reaches the presynaptic terminal
2. calcium influx
   - depolarization of terminal opens voltage-gated calcium channels. Ca2+ enter the cell
3. neurotransmitter release
   - calcium triggers synaptic vesicles to fuse with presynaptic membrane
   - neurotransmitters release into the synaptic cleft
4. binding to receptors
   - neurotransmitters diffused and bind to specific receptors on postsynaptic membrane
5. response in postsynaptic cell
   - the binding opens ion channels
   excitatory: lead to depolarization and trigger action potential
   inhibitory: prevent action potential
6. termination
   - neurotransmitters removed from synaptic cleft enzymatic degradation, reuptake into presynaptic neuron or diffusion away from synapse to reset the system for next signal

Question 8

Ionotropic Effects

Answer 8

occurs when neurotransmitter attaches to receptors and immediately opens ion channels

Question 9

metabotropic effects

Answer 9

occur when neutrotransmitters attach to receptor and initiate slower longer lasting metabolic reactions
- chemicals called neuromodulators
1. neurotransmitter attached, it bends the receptor protein that goes through the membrane