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What is systole and diastole?
Systole and diastole describe the phase/state the heart is in during a heartbeat. Systole refers to the heart when contracted, and blood is pumped into the arteries. Diastole refers to the heart when it is relaxed and blood enters the upper chambers.
What is the relaxing phase of the cardiac cycle?
The relaxing phase of the cardiac cycle is called diastole. During diastole, the heart chambers (atria and ventricles) relax, allowing them to fill with blood. This is followed by the contracting phase called systole.
Are both sets of heart valves open during any part of the cardiac cycle?
No, both sets of heart valves are not open at the same time during the cardiac cycle. The atrioventricular valves (bicuspid and tricuspid) are open when the ventricles are relaxed (diastole) to allow blood to flow from the atria to the ventricles. The semilunar valves (aortic and pulmonary) are open when the ventricles contract (systole) to allow blood to be ejected into the arteries.
What phase of the cardiac cycle is longest?
Atria Diastole is the longest (0.7sec)
What percentage of coronary blood flow occurs during diastole?
Myocardial blood supply is from the right and left coronary arteries, which run over the surface of the heart giving branches to the endocardium (the inner layer of the myocardium). Venous drainage is mostly via the coronary sinus into the right atrium, but a small proportion of blood flows directly into the ventricles through the Thebesian veins, delivering unoxygenated blood to the systemic circulation. Oxygen extraction by the tissues is dependent on consumption and delivery. Myocardial oxygen consumption is higher than in skeletal muscle (65% of arterial oxygen is extracted as compared to 25%). Therefore any increased myocardial metabolic demand must be matched by increased coronary blood flow. This is a local response, mediated by changes in coronary arterial tone, with only a small input from the autonomic nervous system.
When does the blood flows through the coronary artery during left ventricular systole or right ventricular systole?
Neither, theoretically the two ventricles contract simultaneously. The coronary arteries begin as two holes just above the leaflets of the aortic valve. During systole the leaflets block the coronary arteries and prevent blood flow to them. It is during diastole (of both ventricles) that blood returns to the coronary vasculature.
What coronary arteries fill with blood to deliver to heart during what phase?
diastole
Why do the coronary arteries carry a greater blood flow during ventricular diastole than they do during ventricular systole?
Because not all of the blood that is in the heart, which was brought in during diastole, is ejected during systole. There is some back flow of blood, which can't make it over the aortic arch because of lack of pressure, into the heart.
When do coronary arteries primarily receive blood flow?
during diastole
Why coronary arteries Aries close to the semilunar valves?
During cardiac systole the left ventricle contracts, the semi lunar valves open and occlude the coronary arteries. During diastole the valves close and because of the elasticity of the aorta which has just been stretched blood now flows into the coronary arteries. The reason for this is that it is easier to supply blood to the cardiac muscle when it is relaxed.
What is meant by systole and diastole?
The ventricles of heart have two states: systole(contraction) and diastole (relaxation). During diastole blood fills the ventricles and during systole the blood is pushed out of the heart into the arteries. The auricles contract anti-phase to the ventricles and chiefly serve to optimally fill the ventricles with blood.http://www.answers.com/systole
Is diastole the highest pressure in the arteries?
No, diastole is the period when a particular chamber of the heart relaxes. the highest pressure period is during systole.
When is the Blood pressure greatest in the arteries?
Blood pressure in the arteries is greatest during systole. Systole is the period of heart contraction, while diastole is the period of heart relaxation.
When does the intra- aortic balloon pump inflate?
The intra-aortic balloon pump inflates during diastole to increase coronary artery perfusion and cardiac output, and deflates during systole to reduce afterload on the heart.
What phase of cardiac cycle do coronary arteries receive blood flow?
The Coronary Arteries receive blood during Diastole. While the heart is contracting, they are squeezed shut and little blood flows through them.
Which artery has the highest blood pressure in body?
The pressure is highest in the arteries and lowest in the veins.
Why is blood pressure highest just after a ventricular systole and lowest during ventricular diastole?
Systole is the phase during which the heart contracts resulting in the movement of blood to the peripheral parts of the body. The contractile force causes increase in the pressure of the arteries, greater than the diastole which makes it possible for the blood to reach the body.
