Session 2- The Heart As A Pump, Control Of Cardiac Output And Anatomy Of The Heart

Question 1

Describe the basic structure, naming the chambers, valves, and main vessels and the

Answer 1

Right,left atrium
Right,left ventricle
Mitral, tricuspid valve- atrioventricular valve
Sino-atrial ventricle valve- aortic valve, pulmonary valve.
Vena Cava, Aorta, Pulmonary veins, pulmonary artery, coronary artery

Question 2

main differences between the right and left heart

Answer 2

Left side has a thicker ventricular wall to deal with the higher pressure
Left has the mitral valve
Left side supplies to the systemic circuit.
Right side supplies to the pulmonary circuit to the lungs.
Reoxgyengated blood on left
Deoxygenated blood on right

Question 3

Systole

Answer 3

Contraction

Question 4

Diastole

Answer 4

Relaxation

Question 5

Describe the sequence of pressure and volume changes in the left atrium and ventricle over a complete cardiac cycle in the normal individual.

Answer 5

Pressure:
Start: Atrial systole: Atrial pressure> ventricular pressure: Bicuspid valve open
Middle: Ventricular systole: Ventricular pressure> atrial pressure valve closes. Rapid ejection
Diastole: Atrial pressure> ventricular pressure
Volume:

Question 6

Dhbufhf

Answer 6

Phase 1: Atrial systole: Atrial pressure> ventricular pressure
Volume in the atrium will decrease, final 10% of ventricular filling occurs.
Phase 2: Isovolumetric contraction.
Ventricular pressure> atrial pressure. Causes mitral valve to close.
Volume in the ventricle stays the same since all valves closed.
Phase 3: Rapid Ejection.
Left Intraventricular pressure exceeds the pressure within the aorta. Aortic valve will open.
Left ventricular volume will decrease.
Left atrial pressure will initially decrease- x descent
Phase 4: Reduced ejection
Left ventricular decreases as the volume decreases.
Left atrial pressure increases due to venous return from the lungs.
Phase 5: Isovolumetric relaxation
Ventricular pressure is lower than the pressure in the aorta
But ventricular pressure is still greater than the atrial pressure, so all valves are closed, no change in volume.
Phase 6: Rapid filling
Intraventricular pressure< atrial pressure
Mitral valves open, rapid ventricular fillings
Phase 7: Reduced fillings
Rate of filling slows down as ventricles reach inherent relaxed volume.

Question 7

Explain the origin of the 1st and 2nd heart sounds

Answer 7

1st heart sound: Mitral valve closes

THE 2nd heart sound: Aortic valve closes

Question 8

Aortic valve stenosis- valve doesn’t open properly

Answer 8

Cause: Senile calcificati

At systole there’s a crescendo- decrescendo murmur

Question 9

Common conditions associated with cardiac valves and how these may be assessed.

Answer 9

Aortic valve stenosis: murmur - doesn’t open- obstruction to blood flow when valve normally open.
Aortic valve regurgitation: doesn’t close all the way- back leakage.
Murmur at S2. Increase stroke volume, systolic pressure increases, LV hypertrophy
Mitral valve regurgitation: Murmur S2
Mitral valve stenosis: Diastolic rumble

Question 10

Define cardiac output and explain how it is controlled

Answer 10

The total blood ejected from the heart per minute.
Cardiac output= Stroke volume * Heart rate
It is controlled by the the stroke volume, heart rate, total peripheral resistance, venous pressure

Question 11

Define preload

Answer 11

Amount of ventricles are stretched in diastole- related to the end diastolic volume or central venous pressure.

Question 12

Define afterload

Answer 12

The load the heart must eject blood against

Question 13

Define contractility

Answer 13

Contractility is the force of contraction for a given fibre length

Question 14

Explain the Frank-Sterling of the heart

Answer 14

Increased filling of the heart, the harder it contracts, causes a bigger stroke volume.