Cardiovascular Intro

Question 1

Describe the heart’s chambers and their valves.

Answer 1

Inferior and superior vena cave drain into the R) atrium —> through the R) atrio-ventricular valve (tricuspid) into R) ventricle —> through semilunar valve (pulmonary valve) into pulmonary artery —> lungs —> O2 blood back into L) atrium via pulmonary veins —> through L) atrio-ventricluar valve (bicuspid/mitral) into L) ventricle —> out via aortic valve and then systemic circulation.

Question 2

Describe what is happening in the Wiggers diagram.

Answer 2

Question 3

What is EDV?

Answer 3

End Diastolic Volume

Question 4

What is ESV?

Answer 4

End Systolic Volume

The volume of blood in ventricle at the end of systole, when the ventricle contraction is completed (~50 ml).

Question 5

Describe SV?

Answer 5

Stroke Volume

The volume of blood ejected into aorta or pulmonary trunk during one cardiac cycle (~75 ml).

SV = EDV - ESV

Question 6

Ejection fraction = …

Answer 6

SV/EDV

(usually 65%)

Question 7

Describe a pressure volume loop

Answer 7

Question 8

How does a change in ‘preload’ affect the pressure-volume loop?

Answer 8

Increases the ventricle filling volume.

Therefore increaseds SV.

The PV-loop goes towards the R) further.

Question 9

How does ‘afterload’ affect the pressure-volume loop?

Answer 9

Increased pressure in ventricle to overcome the afterload —> increased ejection velocity. But reduced stroke volume.

Question 10

How does ‘contractility’ affect the pressure-volume loop?

Answer 10

The shape of the loop is affected by the contractility and compliance of the ventricle and factors that change refilling or ejection of the ventricle.

End Systolic Pressure-volume Relationship reflects the

Question 11

What are the determinants of myocardial oxygen supply and demand?

Answer 11

Question 12

What are the determinants of Coronary Blood Supply?

Answer 12

1. Mechanical: external compression is exerted on the coronary vessels during the cardiac cycle
2. Metabolites: hypoxia, K+ ions, lactic acid, adenosine, nitric oxide, H2O2, arachidonic acid metabolites
3. Hormones: adrenaline (β2-mediated vasodilation)
4. Neural Factors: sympathetically driven α-mediated vasoconstriction is overwhelmed by metabolic vasodilation

Question 13

Interpret simple Chest x-ray?

Answer 13

Question 14

What are the mechanisms that maintain normal BP?

Answer 14

Baroreceptors (carotid/aortic) sense change in elasticity of the vessel wall.

Sends message to Medulla.

Medulla fires out sympathetic or para-sympathetic message to heart and blood vessels.

Heart rate: increase/decrease
Heart contractility: increase/decrease

Blood vessels: vasoconstriction (increase/decrease)