Pathway of blood
What chamber does blood enter first in the heart?
Right Atrium
What is the phase when ventricles are relaxed and filling with blood?
Ventricular filling
What is the function of heart valves?
Prevents the backflow of blood into the heart
What structure in the heart starts the electrical impulse for contraction?
Sinoatrial (SA) node
What causes blood to move from the atria to the ventricles?
Atrial contraction and the opening of AV valves
What valve does blood pass through when moving from the right atrium to the right ventricle?
Tricuspid Valve
What phase occurs when the ventricles contract but no blood is ejected yet?
Isovolumetric contraction
Which two valves separate the atria from the ventricles?
Tricuspid and mitral (bicuspid) valves
What is the role of the AV node in the cardiac cycle?
Delaying the impulse to allow the atria to contract before the ventricles
What happens to ventricular pressure during isovolumetric contraction?
It increases rapidly
Where does blood go immediately after leaving the right ventricle?
Pulmonary artery
What phase of the cardiac cycle is when blood is actively pumped out of the ventricles?
Ventricular ejection
Which valves open during ventricular ejection?
Pulmonary and aortic valves
What pathway carries electrical signals through the ventricles?
Bundle branches and Purkinje fibers
Why does blood leave the heart during ventricular ejection?
Ventricular pressure is higher than arterial pressure
What chamber of the heart receives oxygenated blood from the lungs?
Left Atrium
What happens to the heart during the isovolumetric relaxation phase?
Pressure drops and the semilunar valves close
Why do the AV valves close during ventricular contraction?
To prevent backflow of blood into the atria
What happens if the SA node stops functioning properly?
The AV node takes over at a slower rate
What causes the semilunar valves to close?
A drop in ventricular pressure after contraction
What is the last valve blood passes through before entering systemic circulation?
Aortic valve
What phase corresponds to the first heart sound (lub)?
Isovolumetric contraction (when AV valves close)
What heart condition occurs when a valve does not fully close, leading to backflow?
Regurgitation
What part of the electrocardiogram (ECG) represents ventricular contraction?
QRS complex
How does high blood pressure affect the heart’s workload?
It forces the heart to work harder to eject blood