Describe the basic structure of the heart?
chambers, valves, main vessels, differences between left and right
What attaches the valves to papillary muscle and why?
- Stop inversion of the valve during systole
What does a stenosis mean in heart valves?
Valve doesn’t open enough and there is obstruction to blood flow.
What is systole?
It is the period involving the contraction of the left ventricle myocardium and opening of the aortic valve
What is diastole?
It is a period of relaxation between contractions. Ventricular filling occurs (Aortic valve closes and Aorta recoils).
What is distinctive about Cardiac muscle compared to other types of muscle?
What is regurgitation of heart valve?
Valve doesn’t close all the way so there is back leakage when valve should be closed
What are the causes of aortic valve stenosis?
What are the results of aortic valve stenosis?
Less blood can get through the valve.
What are the causes of Aortic valve regurgitation?
Caused by
What are causes of mitral valve regurgitation?
What is the main cause(99.9%) of Mitral valve stenosis?
Rheumatic fever. Commissural fusion of valve leaflets makes it harder for blood to flow from LA to LV.
What produces the 1st heart sound(S1)?
Closure of the tricuspid and mitral valve.
What produces the 2nd heart sound(S2)?
Closure of the aortic and pulmonary valve.
What is cardiac output?
Stroke volume X heart rate. Volume of blood pumped out per min
What is preload?
Amount the ventricles are stretched in diastole. Related to end diastolic volume.
What is afterload?
The load the heart must eject blood against. Roughly equivalent to aortic pressure.
What is contractility?
The force of contraction given the fibre length
Explain the Frank-Starling law of the heart?
The more the heart fills with blood, the greater the stretch in the heart fibres and the harder the contraction of the heart so greater stroke volume from the heart.
What can cause the heart to fill with more Blood?
Increase in the Venous pressure.
What is the peripheral resistance?
Resistance to blood flow offered by all the systemic vasculature.
How does contraction of arteriole affect the blood pressure when cardiac output is the same?(converse is true)
What is compliance and when does it change?
What happens when the left ventricle fills up with too much blood and why?
Left ventricular distension. This is because the sarcomere is too stretched so the myosin head cannot attach well to the actin filaments for the ratchet mechanism to occur.