Neurophysiology Part 2

Question 1

What are the 2 synaptic connections?

Answer 1

Axodendritic & axosomatic

Question 2

Axodendritic are between ____?

Answer 2

Axon terminals of 1 neuron and dendrites of others

Question 3

Axiomatic are between ___?

Answer 3

Axon terminals of 1 neuron and soma (cell body) of others

Question 4

What is the first less common synapse connections?

Answer 4

Axoaxonal: axon to axon

Question 5

What is the second less common synapse connection?

Answer 5

Dendrodendritic: dendrite to dendrite

Question 6

What is the third and last less common synapse connection?

Answer 6

Somatodendritic: dendrite to soma

Question 7

What are the 2 main types of synapses?

Answer 7

Chemical synapse & electrical synapse

Question 8

What is the function of chemical synapses?

Answer 8

Specialized for release & reception of chemical neurotransmitters

Question 9

What two parts make up chemical synapses?

Answer 9

1. An axon terminal of presynaptic neuron that contains synaptic vesicles filled w/ neurotransmitter
2. A receptor region on postsynaptic neuron’s membrane that receives neurotransmitter

Question 10

The receptor region of a chemical synapse is usually on ___?

Answer 10

Dendrite or cell body

Question 11

The axon terminal of presynaptic neuron and the receptor region of the chemical synapse are separated by what?

Answer 11

Fluid filled synaptic cleft

Question 12

What happens to electrical impulse and chemical in chemical synapse?

Answer 12

Electrical impulse is changed to chemical across synapse, then back into electrical

Question 13

What does the synaptic cleft prevent the nerve impulse from doing?

Answer 13

From directly passing from 1 neuron to the next, ensuring unidirectional communication between neurons

Question 14

In chemical synapses, what does the chemical event depend on?

Answer 14

The release, diffusion, and receptor binding of neurotransmitters

Question 15

There are how many steps in the transfer of info across chemical synapses?

Answer 15

6 steps in process

Question 16

Step 1 of info transfer across chemical synapse is ___?

Answer 16

Action potential arrives at axon terminal of presynaptic neuron

Question 17

Step 2 of info transfer across chemical synapses is ___?

Answer 17

Voltage gated Ca2+ channels open, and Ca2+ enters axon terminal

Question 18

Step 3 of info transfer across chemical synapse is ___?

Answer 18

Ca2+ entry causes synaptic vesicles to release neurotransmitter into synaptic cleft

Question 19

Step 4 of info transfer across chemical synapse is ___?

Answer 19

The neurotransmitter diffuses across the synaptic cleft and binds to specific receptors on the postsynaptic membrane (often chemically gated ion channels)

Question 20

The binding of the neurotransmitter in step 4 of info transfer across chemical synapse opens ____?

Answer 20

ion channels, creating graded potentials in postsynaptic cell which can be excitatory or inhibitory

Question 21

Graded potentials will continue caused by binding of neurotransmitter that opens ion channels under what condition?

Answer 21

As long as the neurotransmitter is binding to receipt so process needs to be regulated

Question 22

However, a few milliseconds, within neurotransmitter effect is ___ in 1 of ___ ways?

Answer 22

terminated in 1 of 3 ways

Question 23

What are the 3 ways within neurotransmitter effect it is terminated?

Answer 23

Either reuptake, degradation, or diffusion

Question 24

Reuptake is by ___?

Answer 24

Astrocytes or axon terminal

Question 25

Degradation is by ___?

Answer 25

Enzymes

Question 26

Termination by diffusion is ____?

Answer 26

Away from the synaptic cleft

Question 27

What is less common than chemical synapses?

Answer 27

Electrical synapses where neurons are electrically coupled

Question 28

The neurons in electrical synapses are joined by what and is how is communication?

Answer 28

Joined by gap junctions that connect cytoplasm of adjacent neurons, & communication is very rapid (may be unidirectional or bidirectional)

Question 29

Where can electrical synapses be found?

Answer 29

In some brain regions that are responsible for eye movements or hippocampus in areas involved in emotions and memory

Question 30

Based on what factors do graded potentials vary in strength?

Answer 30

The amount of neurotransmitter released and time neurotransmitter stays in cleft

Question 31

The two types of postsynaptic potentials are ___ & ___, depending on effect of chemical synapse?

Answer 31

Excitatory post synaptic potentials (EPSP) & inhibitory post synaptic potentials (IPSP)

Question 32

EPSP involves the neurotransmitter binding to open what?

Answer 32

Chemically gated channels, allowing simultaneous flow of Na+ & K+ in opposite directions

Question 33

What does Na+ influx greater than K+ efflux result in regarding synapses?

Answer 33

In local net graded potential depolarizations called EPSP

Question 34

EPSP trigger ___ if it is of what?

Answer 34

action potential if it is of threshold strength

Question 35

Inhibitory synapses involves neurotransmitter binding to receptor, opening chemical gated channels that allow what to occur?

Answer 35

The entrance and exit of ions that cause hyperpolarization, making postsynaptic membrane more permeable to K+ or Cl-

Question 36

If K+ channels open in inhibitory synapses, it moves ___ of the cell?

Answer 36

out

Question 37

If Cl- channels open, it moves ___ the cell?

Answer 37

into

Question 38

Inhibitory synapses reduces postsynaptic neurons ability to ____?

Answer 38

produce an AP due to neuron moving farther away from threshold (makes it more negative)