Pharamcodynamics

Question 1

Define pharmacodynamics.

Answer 1

Is what the drug does to the body and how the body responds.

Question 2

Name the four ways drugs work.

Answer 2

1. Replace missing chemicals or acts as substitutes.
2. Stimulate particular cell activities.
3. Slow down or inhibit particular activities.
4. Interfere with the function of the foreign cells.

Question 3

Name the types of proteins drugs bind to exert their effects on the body.

Answer 3

1. Receptors
2. Enzymes
3. Ion channels
4. Carrier molecules

Question 4

Define the term affinity.

Answer 4

The ability to bind to a receptor.

Question 5

What is the collective name for a chemical that binds to a receptor.

Answer 5

Ligand

Question 6

Describe what it means by lock and key.

Answer 6

A receptor molecule with a specific shape or three dimensional structure and only substances that fit precisely can interact with it.

Question 7

Identify some drugs that mimic naturally occurring substances produced in the body.

Answer 7

Morphine
Phenylephrine
Contraceptive pill

Question 8

Define the term efficacy in terms of pharmacodynamics.

Answer 8

It is the measure of the bound ligand to activate a response.

Question 9

Define the term agonist.

Answer 9

The drug has the same effect on the receptors as does the natural substance that normally binds to the receptors.

Question 10

Define the term antagonist.

Answer 10

The bound drug blocks the binding sites of the natural substance and so prevents its effects. (Plastic plug cover).

Question 11

Describe what a competitive antagonist is.

Answer 11

It is the most common and important type of antagonism. It competes with the agonist for the agonist binding site on the receptor. Because the two are in competition, increasing the agonist concentration can overcome the blocking effect and restore the response.
However, the competitive antagonist forms strong bonds to the agonist site and therefore this block cannot be overcome.

Question 12

Describe what a non-competitive antagonist is for.

Answer 12

They bind to a site other than the agonist binding site. They cause a conformational change in the receptor which reduces the ability of the agonist to bind to its binding site. This reduces the response to the agonist.

Question 13

Describe Alpha-receptors.

Answer 13

They are associated mainly with increased contractibility of vascular smooth muscle and intestinal relaxation.

Question 14

Describe Beta-receptors.

Answer 14

They are associated with vasodilation and relaxation of non-intestinal smooth muscle and cardiac stimulation.

Question 15

Define the term enzyme.

Answer 15

A protein which acts as a biological catalyst.

Question 16

Give an example of an irreversible enzyme inhibitor which used in a clinic.

Answer 16

Ibuprofen

Question 17

NSAISs are examples of drugs that block the activity of an enzyme. What does NSAIDs inhibit?

Answer 17

Cyclo-oxygenase (COX)

Question 18

What are Acetylcholinesterase used for?

Answer 18

It is a neurotransmitter that helps with memory and thinking.
People with Alzheimer’s disease use this to stabilise or improve their symptoms.

Question 19

How does Acetylcholinesterase stabilise symptoms of Alzheimer’s?

Answer 19

It breaks down acetylcholine in the synapse. By inhibiting the breakdown of the acetylcholine more of this neurotransmitter would remain in the synapse and enhance memory.

Question 20

Name the ions that interfere with the movement of ions across cell membranes.

Answer 20

Sodium,calcium and potassium.

Question 21

Give an example of a common drug which affects ion channels.

Answer 21

Calcium channel blocker ( Often used to treat hypertension or angina).

Question 22

Describe what calcium channel blockers does.

Answer 22

They act as vasodilators by blocking the intracelluar calcium required for the contraction of arteriole smooth muscle.
This vasodilation causes a reduction in peripheral vascular resistance (PVR) leading to reduced blood pressure.

Question 23

Name a drug that affects ion channels (modulators).

Answer 23

Benzodiazepines acts as modulators of the GABAa receptor.

Question 24

Name a drug that affects transport carriers/proteins.

Answer 24

SSRIs which prevent the reuptake of serotonin from the synaptic cleft back into the pre-synaptic neurone.
One of the actions of serotonin in the CNS is as mood enhancer.

Question 25

What are sodium channels vital for?

Answer 25

They are vital to the propagation of the action potential along nerve cells.
They block the sensation of pain.

Question 26

What do potassium channel blockers prevent?

Answer 26

Amiodarone-used to prevent arrhythmias.

Question 27

What do potassium channels openers responsible for?

Answer 27

They are responsible to treat hypertension or angina as they relax smooth muscle causing vasodilation.