for the first time development of four chambered heart is seenin
Answers
Development starts when the first mesodermal cells migrate anterolaterally and form the bilateral heart-forming regions during gastrulation. ... During septation, the heart tube is separated into a right, pulmonary, and a left, systemic, halve.
••
In four chambered heart, left half is completely separated from right half by septa. It serves following two purposes (a) ensures complete segregation of oxygenated and deoxygenated blood (i.e., no mixing). (b) allows a highly efficient supply of oxygenated blood to all parts of the body.
••
The heart's rate of pumping oxygen-rich blood is fastest in infancy, about 120 beats per minute. As a child grows, the heart rate slows down. A seven-year-old child's heart beats about 90 times per minute. By the age of 18, the heart rate stabilizes to about 60- 100 beats per minute.