Unit 3

Question 1

neuropeptides

Answer 1

peptides found in the nervous system.
Small proteins in the nervous system that act as neurotransmitters or neuromodulators.

Question 2

neuromodulators

Answer 2

Chemicals that don’t follow the typical neurotransmitter model. They may regulate neurotransmitter activity or act at distant sites from their point of release.
Can alter the action of a standard neurotransmitter by enhancing, reducing, or prolonging the transmitter’s effectiveness

Question 3

steps of neurotransmitter synthesis, release and inactivation

Answer 3

1) synthesis
2) received action potential
3) depolarization open gated CA2+ channels
4) Ca2+ ions through cannels
5) Ca2+ cause fusion to presynaptic membrane
6) neurotransmitter released into synaptic cleft (exocytosis)
7) neurotransmitter binds with receptor molecules
8) post synaptic channels open/close
9) changing excitability of the post synaptic cell

Question 4

Major families of neurotransmitters

Answer 4

1) Amino Acids
2) monoamine
3) lipid- synthesized on demand and not stored
4) Neuropeptide
5) Gaseous- synthesized on demand and not stored

Question 5

second messengers

Answer 5

Substance that, when activated by signaling molecules bound to receptors in the cell membrane, will initiate biochemical processes within the cell.

Question 6

mechanisms of hormone action

Answer 6

release of chemical substances (hormones) from endocrine glands, target cells must have hormone receptors. Can travel long distances through blood stream.

Question 7

importance of the endocrine system

Answer 7

a network of glands that produce and release hormones — chemical messengers that travel through the bloodstream to regulate the body’s functions.
Secret hormones (monoamines) fight or flight, mobilize glucose for energy.
works closely with the nervous system to maintain homeostasis, growth, and reproduction.

Question 8

synapse

Answer 8

Structural unit of information transmission between two nerve cells. It consists of the presynaptic nerve terminal, the synaptic cleft, and a small area of the postsynaptic cell that receives the incoming signal.

Question 9

neurotransmitter

Answer 9

chemical substance synthesized in a group of nerve cells and released by those cells to be received by postsynaptic cells. They are used to carry signals between cells.

Question 10

classical neurotransmitter

Answer 10

discovered prior to all other categories and follow certain principles of transmission

Question 11

how is the synaptic transmitter action of a released chemical terminated?

Answer 11

• removing neurotransmitter molecules from the synaptic cleft through:
• enzymatic breakdown (classical transmitters)
• reuptake at axon terminal, from cell that released the transmitter eg. SSRIs
• uptake by glial cells

Question 12

two major types of receptors

Answer 12

1) Ionotropic- legand-gated ion channels. Fast acting, short term eg. muscle contraction. direct connect to ion channels and opens channel.
2) metabotropic- G protein-coupled GPCRs. Not an ion channels bonds to G-protein, triggers secondary messenger systems.

Question 13

why is nitric oxide considered to be an atypical neurotransmitter?

Answer 13

Nitric oxide is considered an atypical neurotransmitter because it is not stored or released like normal neurotransmitters.
It’s made on demand, diffuses directly between cells, acts inside the target cell, and breaks down quickly

Question 14

4 ways in which drugs can alter synaptic transmission

Answer 14

• increase or decrease rate of transmitter synthesis
• block enzymes that break down neurotransmitters leading to increased amount of transmitter
• block transporters increasing neurotransmitter in the synaptic cleft
• controls storage or release creating weaker signals or failed signals
• stimulating or inhibiting auto receptors that control release process
• hormone secretion

Question 15

hypothalamic-pituitary axis

Answer 15

links the brain and endocrine system.
It allows the hypothalamus (in the brain) to control hormone release from the pituitary gland, which in turn regulates many body functions such as growth, reproduction, stress response, and metabolism.
The anterior pituitary is controlled through blood-borne releasing hormones from the hypothalamus.

The posterior pituitary receives direct nerve signals, releasing oxytocin and vasopressin straight into the blood.

Question 16

two types of synapses

Answer 16

electrical
chemical

Question 17

receptors

Answer 17

Proteins located on the surface of or within cells that bind to specific ligands to initiate biological changes within the cell.

Question 18

antagonist

Answer 18

drug blocks or inhibits the ability of the neurotransmitter to activate the receptor

Question 19

agonist

Answer 19

drug agonist is a chemical compound that binds to and activates a specific receptor protein, mimics the action of the neurotransmitter in activating the receptor

Question 20

3 characteristics of neurotransmitter receptors

Answer 20

1. Their role is to pass a signal. receptors do not carry neurotransmitter molecules across the cell membrane.
2. Different varieties of receptors for the same transmitter are called receptor subtypes, add complexity.
3. most neurotransmitter receptors fall into two broad categories: ionotropic receptors and metabotropic receptors.

Question 21

The endocrine system is important to pharmacologists

Answer 21

1) Drugs can change hormone secretion → leading to physical or reproductive effects.

2) Hormones can alter drug sensitivity and response.

3) Some hormones have drug-like (psychoactive) effects.

4) Hormone levels can indicate how drugs or diseases affect brain neurotransmitter systems.

Question 22

organization of the hypothalamic-pituitary axis

Answer 22

The organization of the hypothalamic pituitary axis involves axon terminals of hypothalamic releasing hormone neurons near blood capillaries in the median eminence, while oxytocin and vasopressin neurons send their axons into the posterior lobe of the pit