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This diagram shows how the hemolymph is circulated throughout the body of a grasshopper. The hemolymph is first pumped through the heart, into the aorta, dispersed into the head and throughout the hemocoel, then back through the ostia that are located in the heart, where the process is repeated.
In vertebrates, the circulatory system is a system of organs that includes the heart, blood vessels, and blood which is circulated throughout the body. [1] [2] It includes the cardiovascular system, or vascular system, that consists of the heart and blood vessels (from Greek kardia meaning heart, and Latin vascula meaning vessels).
The heart is the driver of the circulatory system, pumping blood through rhythmic contraction and relaxation. The rate of blood flow out of the heart (often expressed in L/min) is known as the cardiac output (CO). Blood being pumped out of the heart first enters the aorta, the largest artery of the body.
The heart did not pump blood around, the heart's motion sucked blood in during diastole and the blood moved by the pulsation of the arteries themselves. [93] Galen believed the arterial blood was created by venous blood passing from the left ventricle to the right through 'pores' between the ventricles. [ 90 ]
It pumps blood from the body — called the systemic circulation — through the lungs — called the pulmonary circulation — and then back out to the body. This means that the heart is connected to and affects the entirety of the body. Simplified, the heart is a circuit of the circulation. [citation needed] While plenty is known about the ...
In a healthy heart all activities and rests during each individual cardiac cycle, or heartbeat, are initiated and orchestrated by signals of the heart's electrical conduction system, which is the "wiring" of the heart that carries electrical impulses throughout the body of cardiomyocytes, the specialized muscle cells of the heart.
The blood in the atria is pumped into the heart ventricles through the atrioventricular mitral and tricuspid heart valves. There are two atria in the human heart – the left atrium receives blood from the pulmonary circulation, and the right atrium receives blood from the venae cavae of the systemic circulation.
The aortic and pulmonary valves known as the semilunar valves open, and a defined fraction of blood within the heart is ejected into the aorta and pulmonary trunk. Ejection of blood from the heart is known as systole. Ejection causes pressure within the ventricles to fall, and, simultaneously, the atria begin to refill (atrial diastole).