CHAPTER 2 - Chemical Events at the Synapse (Module 2.2)

Question 1

who is otto loewi?

Answer 1

he is the guy who discovered the chemical transmission of nerve impulses with a frog’s heart

Question 2

What was Loewi’s evidence that neurotransmission depends on the release of chemicals?

Answer 2

When Loewi stimulated a nerve that increased or
decreased a frog’s heart rate, he could withdraw fluid from the area around the heart, transfer it to another frog’s heart, and thereby increase or decrease its
rate also.

Question 3

Blood flow increases to the most active brain areas. How does the blood “know” which areas are most active?

Answer 3

In a highly active brain area, many stimulated neurons release nitric oxide, which dilates the blood vessels in the
area and thereby makes it easier for blood to flow to the area

Question 4

what are neurotransmitters?

Answer 4

chemicals released by a neuron that affects another neuron

Question 5

what is nitric oxide?

Answer 5

it is a gas released by many local neurons that is poisonous in large quantities yet neurons contain an enzyme that allows them to make it efficiently

Question 6

what do neurons synthesize almost all neurotransmitters from?

Answer 6

amino acids

Question 7

what is epinephrine, norepinephrine and dopamine known as?

Answer 7

they are known as catecholamines because they contain a catechol group and an amine group

Question 8

Name the three catecholamine neurotransmitters.

Answer 8

Epinephrine, norepinephrine, and dopamine.

Do not confuse the term catecholamine with acetylcholine

Question 9

what is exocytosis?

Answer 9

bursts of release of neurotransmitter
from the presynaptic neuron

Question 10

When the action potential reaches the presynaptic terminal, which ion must enter the presynaptic terminal to evoke release of the neurotransmitter?

Answer 10

Calcium

Question 11

what are the channels controlled by a neurotransmitter called?

Answer 11

transmitter-gated or ligand-gated channels

Question 12

what is a ligand?

Answer 12

it is a chemical that binds to something

Question 13

what is the most abundant neurotransmitter in the nervous system?

Answer 13

glutamate

Question 14

Why does the nervous system use so many chemicals, if they all produce the same type of message?

Answer 14

they do not produce the same type of message since it is more complicated and more varied, when a neurtransmitter attaches to its receptor, it may exert a IONOTROPIC EFFECT or a METABOTROPIC EFFECT

Question 15

what is a G protein?

Answer 15

a protein coupled to guanosine triphosphate (GTP), an energy-storing molecule

Question 16

what are neuropeptides also referred to as?

Answer 16

neuromodulators, because they have properties that set them apart from other transmitters

Question 17

How do ionotropic and metabotropic synapses differ in speed and duration of effects?

Answer 17

Ionotropic synapses act more quickly and more briefly

Question 18

What are second messengers, and which type of synapse
relies on them?

Answer 18

Second messengers are chemicals that alter
metabolism or gene expression within a postsynaptic neuron.
At metabotropic synapses, the neurotransmitter attaches to a receptor and thereby releases a second messenger

Question 19

How do neuropeptides compare to other transmitters?

Answer 19

Neuropeptides are released only after
prolonged stimulation, but when they are released, they are released in large amounts by all parts of the neuron,
not just the axon terminal.

Neuropeptides diffuse widely, producing long-lasting effects on many neurons.

Question 20

How do LSD, nicotine, and opiate drugs influence behavior?

Answer 20

SD binds to one type of serotonin receptor.

Nicotine
binds to one type of acetylcholine receptor.

Opiates bind
to endorphin receptors.

Question 21

what is reuptake

Answer 21

is a biological process in psychology that involves the reabsorption of neurotransmitters after they have transmitted a neural impulse

Question 22

what does reuptake occur through?

Answer 22

special membrane proteins called TRANSPORTERS

Question 23

what inhibits the transporters for dopamine, serotonin, and norepinephrine

Answer 23

stimulant drugs, including amphetamine and cocaine

Question 24

What happens to acetylcholine molecules after they stimulate a postsynaptic receptor?

Answer 24

The enzyme acetylcholinesterase breaks acetylcholine molecules into two smaller molecules, acetate and choline, which are then reabsorbed by the presynaptic terminal

Question 25

What happens to serotonin and catecholamine molecules
after they stimulate a postsynaptic receptor?

Answer 25

Most serotonin and catecholamine molecules are reabsorbed by the presynaptic terminal. Some of their molecules are broken down into inactive chemicals, which then diffuse away

Question 26

How do amphetamine and cocaine influence synapses?

Answer 26

They block reuptake of released dopamine, serotonin, and norepinephrine.

Question 27

Why is methylphenidate generally less disruptive to behavior than cocaine is despite the drugs’ similar mechanisms?

Answer 27

The effects of a methylphenidate pill develop and decline in the brain much more slowly than do those of cocaine.

Question 28

what will happen to transmitter molecules that the transporters do not take?

Answer 28

they will break down by an enzyme called COMT

Question 29

what are autoreceptors?

Answer 29

receptors that respond to
the released transmitter by inhibiting further synthesis and
release.

Question 30

what are the active chemicals in marijuana called?

Answer 30

cannabinoids

Question 31

How do cannabinoids affect neurons?

Answer 31

Cannabinoids released by the postsynaptic neuron
attach to receptors on presynaptic neurons, where they inhibit further release of both glutamate and GABA.

Question 32

is a chemical secreted by cells in one part of the body and conveyed by the blood to influence other cells.

Answer 32

a hormone

Question 33

Which part of the pituitary—anterior or posterior—is neural tissue, similar to the hypothalamus?

Answer 33

The posterior pituitary is neural tissue, like the hypothalamus

Question 34

Which part of the pituary is glandular tissue and produces hormones that control the secretions by
other endocrine organs?

Answer 34

The anterior pituitary is glandular tissue and produces hormones that control several other endocrine organs

Question 35

In what way is a neuropeptide intermediate between neurotransmitters and hormones?

Answer 35

Ordinary neurotransmitters are released in small amounts close to their receptors.

Neuropeptides are released into a brain area in larger amounts or not at all. When released, they diffuse more widely. Hormones
are released into the blood for diffuse delivery throughout
the body.