Pathway of blood
What chamber does blood enter first in the heart?
Right Atrium
What is the alternating contraction and relaxation phases of the heart chambers?
Cardiac cycle
What is the function of heart valves?
Prevents the backflow of blood into the heart
What structure in the heart initiates the electrical impulses 70-80 times per minutes 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 atria completes the emptying of blood into the ventricles and the ventricles are relaxed and filling with blood?
Ventricular filling
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?
It allows time for atria to finish it’s contraction phase before sending impulse on to ventricles to begin contracting (delays impulses approximately 0.1 second)
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 occurs when the ventricles contract, AV and SL valves are closed, and pressure increases rapidly but the volume remains the same?
Isovolumetric ventricular contraction
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 phase occurs when the AV valves are closed, the SL valves are open, and blood is actively pumped out of the ventricles?
Ventricular systole (ejection)
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 occurs when AV and SL valves are closed, all chambers relax simultaneously for 0.4 seconds, and the atria passively fills with blood?
Isovolumetric ventricular relaxation (diastole)
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