Cardiac Cycle Flashcards
What are the 2 main features which determine direction of flow?
Pressure
Valves
What is the effect on the valves when the pressure increases?
Pressure INCREASING leads to Valves CLOSING.
Which direction does blood travel in?
Blood travels from HIGH to LOW blood pressure.
Explain the flow of blood through the RIGHT side of the heart (including which type of blood).
Deoxygenated blood is pumped : Right atria to right ventricle then straight to the pulmonary arteries -> to the lungs.
Explain the flow of blood through the LEFT side of the heart (including which type of blood).
Oxygenated blood is pumped : Left atria to left ventricle then straight to the aorta -> to the rest of the body.
What are the main atrioventricular valves (AV)?
Tricuspid
Bicuspid (known as mitral valve)
What are the main semilunar valves?
Pulmonary
Aortic
How does increasing pressure affect the AV and semilunar valves?
AV valves = Close
Semilunar valves = Open
What is systole known as?
The ‘contraction’ phase.
What is diastole known as?
The ‘relaxation’ phase.
What is the time taken for ONE standard heartbeat?
800ms = 0.8s
Give a brief outline of the cardiac cycle.
Atrial systole
Ventricular Systole
Ventricular Diastole
Why does atrial systole occur?
Occurs due to an increase in pressure.
What is isovolumetric contraction?
This is when the ventricles CONTRACT but there is NO movement of blood.
How does pressure control the semilunar valves?
Pressure is HIGH = semilunar valves OPEN.
Pressure is LOW = semilunar valves CLOSE.
