The Cardiovascular System

Question 0

How does aspirin work as an anti platelet?

Answer 0

It irreversible blocks the COX enzyme which reduces thromboxone (TxA2) synthesis preventing platelets coming together or reproducing.

Question 1

How do anticoagulants work?

Answer 1

Heparin - natural anticoagulant which activated antithrombin which blocks the conversion of prothrombin to thrombin and fibrinogen into fibrin.
Warfarin - antagonises the vitamin K role in various clotting factors

Question 2

How does didyridamole work as an anti platelet drug?

Answer 2

It inhibits phosphodiesterone enzyme which prevents the breakdown of cAMP, lowering aggregation.

Question 3

How does clopidogrel work as an anti platelet?

Answer 3

It inhibits glycoproteins IIb/IIIa receptor expression on platelets which are usually the ‘final pathway’ for platelet aggregation.

Question 4

How do fibrinolytic/thrombolytic drugs work?

Answer 4

They convert active plasminogen into active plasmin which is an enzyme that digests fibrin.

Question 5

What are examples of drugs that are used to treat blood clots?

Answer 5

• Heparin

- Warfarin

Question 6

What are examples of anti platelet drugs?

Answer 6

• Asprin
• Didyridamole
• Clopidogrel

Question 7

What are examples of fibrinolytic/thrombolytic drugs?

Answer 7

• Altepase

- Streptokinase

Question 8

What are the 4 types of anti-arrhythmia drugs?

Answer 8

Type 1 - Sodium Channel Blockers
Type 2 - Beta 1 Adrenoreceptor Blockers
Type 3 - Potassium Channel Blockers
Type 4 - Calcium Channel Blockers

Question 9

How do Sodium Channel Blockers help arrhythmia?

Answer 9

They block sodium during action potentials.
1a - depresses phase 0 causing a prolonged duration of action potential.
1b - depresses phase 0 causing a shortened duration of action potential.
1c - depresses phase 0 causing a slowing of conduction stopping action potential.

Question 10

How do beta-1 Adrenoreceptor blockers help arrhythmias?

Answer 10

They block the beta receptors causing a depression of Phase 4 of action potential, slowing the recovery of cells and slowing conduction and a decrease of the automaticity of the heart.

Question 11

How do potassium channel blockers help arrhythmias?

Answer 11

They block the potassium channels prolonging phase 3 of action potential which prolongs repolarisation and slows conduction of the heart.

Question 12

How do calcium channel blockers help arrhythmias?

Answer 12

Blocks calcium channels causing a depression of depolarisation and prolonged phases 1 and 2 of repolarisation which slows automaticity and conduction.

Question 13

What is an example of a sodium channel blocker used to treat arrhythmias?

Answer 13

1a - Disopyramide, Procainamide, Quinidine.
1b - Lidocaine, Amiodarone, Mexiletine
1c - Flecainide and Propafenone.

Question 14

What are examples of beta 1 Adrenoreceptor blockers used to treat arrhythmias?

Answer 14

• Acebutolol
• Esmolol
• Propanolol

Question 15

What is an example of a potassium channel blocker used to treat arrhythmias?

Answer 15

• Amiodarone

- Sotalol

Question 16

What is an example of a calcium channel blocker used to treat arrhythmia?

Answer 16

• Diltazem

- Veraprimil

Question 17

What drug is used to treat angina and how does it work?

Answer 17

• Glyceral Trinitrate (GTN)
  It causes direct relaxation of smooth muscle causing a decrease in venous return and arterial pressure. It also reduces cardiac workload and oxygen consumption.