A human beings heart is about the size of it of that human beings fist. As the body develops, the heart grows at the analogous rate as the fist. So an infants heart and fist atomic number 18 about the same size at birth. In the womb, however, that similarity was not always true. During the first few weeks after conception, the foetal heart occupies most of the fetus mid-section. The heartsize to bodysize ratio is nine times great in the fetus than in the infant. During those first few weeks, the foetal heart lies high in the chest. Soon, it moves down to occupy its side of meat in the chest cavity.
There are several phases of the fetal hearts development. At first, the heart is just a tube. It grows so flying that it needs more space, so it bends and twists back, forming the familiar shape. During the adjacent phase, the deuce atria are partly separate but there is just one big ventricle.
The next phase begins when the two atria are completely separate and the ventricles are just descent to separate. Finally, the ventricles separate completely and the heart is developed.
During the fetal hearts developmental stages, the heart actually takes on several distinct appearances. These heart structures agree other animal hearts. During phase one, the tube- care heart is much like a fish heart. The second phase, with two chambers, resembles a catch heart. The three-chambered phase is similar to a snake or polo-neck heart. The final four-chambered heart structure distinguishes the human heart.If you want to deposit a full essay, order it on our website: Ordercustompaper.com
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