Chapter 5 Pt.2

Question 1

What is the first step to anterograde synaptic transmission

Answer 1

The neurotransmitters are synthesized (created) in the neuron

Question 2

What are Transporters

Answer 2

protein molecules that move substances across cell membranes, and package some neurotransmitters into vesicles

Question 3

What is the second step in anterograde synaptic transmission

Answer 3

The neurotransmitter is packaged and stored within vesicles at the axon terminal

Question 4

What is step 3 for the Anterograde synaptic transmission

Answer 4

The neurotransmitter is transported to the presynaptic membrane and released into the synaptic cleft

Question 5

How is the neurotransmitter released into the synaptic cleft? (step 3)

Answer 5

Through an action potential that opens the gate for calcium (Ca2+) to influx the axon terminal.
Because of the calcium influx, the presynaptic membrane empties their contents into the synaptic cleft (exocytosis)

Question 6

What is step 4 of anterograde synaptic transmission

Answer 6

the neurotransmitter binds to and activates receptors on the postsynaptic membrane

Question 7

What are Ionotropic receptors

Answer 7

a membrane protein that acts as a binding site for a neurotransmitter, and also regulates ion flow

Question 8

What is a metabotropic receptor

Answer 8

A membrane protein that acts as a binding site for a neurotransmitter that can open ion channels

Question 9

In addition to interacting with the postsynaptic membranes receptors, a neurotransmitter may interact with receptors on the ___________ membrane. By doing so, it may influence the _____ that just released it. Specifically, a neurotransmitter may activate presynaptic receptors called _____________.

Answer 9

Presynaptic, cell, auto receptors

Question 10

What do Autoreceptors do

Answer 10

they provide information about whether adjustments to synaptic communication should be made

Question 11

The smallest postsynaptic potential is produced by the release of the contents of just 1 synaptic vesicle. This number of neurotransmitter molecules is called a _________.

Answer 11

Quantum (pl.quanta)

Producing a postsynaptic potential large enough to initiate a postsynaptic action potential requires the simultaneous release of many quanta from the presynaptic cell

Question 12

The number of quanta released from the presynaptic membrane in response to a single action potential depends on two factors, what are they?

Answer 12

1) the amount of Ca2+ that enters the axon terminal in response to the action potential
2) the number of vesicles ducked at the membrane, waiting to be released

Question 13

What is the fifth step of anterograde synaptic transmission

Answer 13

The neurotransmitter is removed (or degraded) from the synaptic cleft so it won’t continue to interact with a receptor

Question 14

What are the 4 ways inactivation of a neurotransmitter can happen?

Answer 14

Diffusion = the neurotransmitter simply
diffuses away

Degradation = enzymes break it down

Reuptake = membrane transporters specific to that transmitter bring it back to the presynaptic axon terminal to reuse it

Astrocyte uptake = some neurotransmitters are taken up by the neighbouring astrocytes

Question 15

How do Axoextracellular synapses secrete transmitter chemicals

Answer 15

they secrete it into extracellular fluid

Question 16

How do axosecretory synapses secrete its transmitter

Answer 16

it synapses with blood capillaries and secretes its transmitter directly into blood

Question 17

Synapses are not limited to axon terminals, dendrites also may send messages to other dendrites through _________________ synapses

Answer 17

dendrodendritic synapses

Question 18

Some neurons can influence each other electrically through an _________ _______ (gap junction), where intracellular fluids or cytoplasm can come into direct contact

Answer 18

electrical synapse

Question 19

When is a “Gap Junction” formed

Answer 19

when connexin proteins in one cells membrane crease a hemichannel that connects to a hemichannel in another cells membrane, allowing ions to pass from one neuron to the other

Question 20

What is the difference between Excitatory and Inhibitory synapses

Answer 20

Excitatory: increase the activity of a receiving neuron
Inhibitory: decrease the activity of a receiving neuron

Question 21

When a synapse is sent between axon terminals and cell bodies, its called ______________.

Answer 21

Axo-somatic

Question 22

When a synapse is sent between axon terminals and muscles, its called _____________.

Answer 22

Axo-muscular

Question 23

When a synapse is sent between axon terminals and dendrites (not dendrites to dendrites) its called _____________.

Answer 23

Axo-dentritic

Question 24

When a synapse tis sent between axon terminals and other axons, its called __________.

Answer 24

axo-axonic

Question 25

When a synapse is sent between axon terminals and other “synapses”, its called

Answer 25

Axo-synaptic

Question 26

A _____________ synapse releases chemical transmitters into extracellular fluid

Answer 26

Axo-extracellular

Question 27

A ____________ synapse releases transmitters into the bloodstream as hormones

Answer 27

axo-secretory

Question 28

Excitatory synapses are usually located on a(n) ___________, whereas inhibitory synapses are usually found on a(n) ___________.

Answer 28

Dendrite; cell body/soma