Introductory Lecture

Question 1

Coronary Arteries

Answer 1

Question 2

Three layers of the arterial wall.

Answer 2

• Three layers:

1. Intima (subendothelial layer)
2. Media (middle layer) with smooth muscle cells.
3. Adventitia (outer layer) with connective tissue and nerves.

Question 3

What affect do NO have on arteries?

Answer 3

Causes vasodilation

Question 4

Stages of atherosclerosis:

Answer 4

Question 5

Causes of Chest Pain:

Answer 5

Question 6

Explain myocardial referred pain.

Answer 6

Myocardial ischaemia (the loss of blood flow to a part of the heart muscle tissue) is possibly the best known example of referred pain; the sensation can occur in the upper chest as a restricted feeling, or as an ache in the left shoulder, arm or even hand.

Question 7

History taking of Chest pain:

Answer 7

Question 8

Angina ECG presentation and summary:

Answer 8

Question 9

Describe the JVP waveform.

• watch a video on this.

Answer 9

• a wave: atrial contraction
• c wave: corresponds to right ventricular contraction causing the tricuspid valve to bulge towards the right atrium during RV isovolumetric contraction.
• x descent: closed tricuspid, ventricular systole, atrial relaxation
• v wave: maximal atrial filling
• y descent: emptying of atrium

Question 10

How do the sympathetic and parasympathetic nervous systems control heart rate? What are the mechanisms?

Answer 10

Sympathetic–adrenaline/noradrenaline

Increase the phase 4 slope

By increasing Na+ influx

So the threshold is reached faster -↑HR

Parasympathetic –vagal stimulation –acetylcholine

Increase K+efflux

Lowers Phase 4 slope

• Prolongs time to reach threshold -↓HR

Question 11

What happens to the JVP waveform in atrial fibrillation?

Answer 11

Absent waves.

Question 12

What is orthopnoea?

Answer 12

Shortness of breath which occurs when lying flat.

Question 13

What is the Anrep effect?

Answer 13

The Anrep effect is an autoregulation method in which myocardial contractility increases with afterload.

Question 14

What is active hyperaemia?

Answer 14

Active hyperemia is the increase in organ blood flow (hyperemia) that is associated with increased metabolic activity of an organ or tissue. An example of active hyperemia is the increase in blood flow that accompanies muscle contraction, which is also called exercise or functional hyperemia in skeletal muscle.

Question 15

Why might bradycardia follow an RCA occlusion?

Answer 15

• The RCA supplies the SA nodal artery in 60% of cases and the AV node in 90% of patients
• Without adequate oxygen, ATP levels are diminished
• This depresses the Phase 4 slope
• Increased time to threshold potential = bradycardia

Question 16

How do diuretics affect preload?

Answer 16

Decrease preload.

Question 17

How do diuretics affect cardiac output? Why?

Answer 17

Reduce cardiac output.

Diuretics decrease blood volume and venous pressure. This decreases cardiac filling (preload) and, by the Frank-Starling mechanism, decreases ventricular stroke volume and cardiac output

Question 18

Aortic dissection

Answer 18

Aortic dissection (AD) occurs when an injury to the innermost layer of the aorta allows blood to flow between the layers of the aortic wall, forcing the layers apart. In most cases, this is associated with a sudden onset of severe chest or back pain, often described as “tearing” in character.

Question 19

Angiotensin II constricts which arteriole?

Answer 19

Efferent arteriole

Question 20

What are the different kinds of embolism?

Answer 20

Thromboem

Question 21

Thrombus or embolus affecting where may cause bowel ischaemia?

Answer 21

Mesenteric circulation