Afterload.
left ventricles . as it pump blood to the aorta it needs a high pressure to take blood all over the body . left ventricle is thick as it needs a high pressure to pump blood and to withstand that pressure.
lots :)
Blood can only enter an artery, be it the aorta, when the left ventricle contracts, or the pulmonary arteries, when the right ventricle contracts, which both occur at the same time after ventricular systole which is contraction. Therefore, the answer is contract.
The entrance to the ascending aorta is guarded by the semilunar valve. The semilunar valves are pocketlike structures attached at the point at which the pulmonary artery and the aorta leave the ventricles.
When relaxation or diastole is occurring in the atria blood flows through the atria and the AV valves into the ventricles. When contraction or systole is occurring in the atria the remaining blood that doesn't flow through during relaxation is pushed into the ventricles. As the atria relax, the ventricles begin contracting; ventricular pressure rises, closing the AV valves. Ventricular pressure continues rising until it exceeds the pressure in the large arteries stemming from the ventricles. The SL valves are forced open and blood is expelled from the ventricles into the aorta and pulmonary trunk. During this phase the ventricles relax because the blood is no longer compressed in their chambers. Blood expelled into the aorta and pulmonary trunk backflows toward the heart, which then closes the SL valves. During the ventricle contraction the atria stays in relaxation, filling with blood and when blood pressure on the atrial side of the AV valves exceeds that in the ventricles, the AV valves are forced open and ventricular filling begin all over again.
Ventricular contraction. When ventricular pressure exceeds arterial pressure, the ventricles contract and eject blood into the aorta.
Blood flows into the relaxed atria while the ventricles contract. <rephrased> The ventricles contract, carrying blood into the aorta, and blood flows into the relaxed atria.
The aorta and ventricles..
The aorta .
When after contraction of ventricles of heart, blood is propelled into circulatory system (both systemic and pulmonary circulation) and that pressure is called systolic pressure, witch dilates the aorta and large(and small also) arteries. When ventricles relax in diastole aortic (and pulmonary) valves close down and then aorta and large (and small also)arteries contract, witch are dilated during systole. Peripheral resistance in closed system maintain the lower blood pressure called diastolic blood pressure.
the bottom chambers of the heart are the left and right ventricles and pump blood to the aorta and lungs respectively.
left ventricles . as it pump blood to the aorta it needs a high pressure to take blood all over the body . left ventricle is thick as it needs a high pressure to pump blood and to withstand that pressure.
The pulmonary artery and the aorta lead upward and away from the ventricles. Since the ventricles contract from the bottom, blood is more efficiently pushed out of the heart.
lots :)
ejection period
Blood can only enter an artery, be it the aorta, when the left ventricle contracts, or the pulmonary arteries, when the right ventricle contracts, which both occur at the same time after ventricular systole which is contraction. Therefore, the answer is contract.
The entrance to the ascending aorta is guarded by the semilunar valve. The semilunar valves are pocketlike structures attached at the point at which the pulmonary artery and the aorta leave the ventricles.