Why is double circulation of blood necessary in human beings?
Class 12th Biology
Asked By Panchi Jaiswal
Double circulation is the flow of blood through the heart twice. Initial
flow is finished when deoxygenated blood is brought to heart and then
pumped to lung for oxygenation. The second flow is from lungs to heart
and then back to the body. The transmission is important as it helps in
oxygenation of blood.
Double circulation describes the fact that our oxygenated and
deoxygenated blood is kept separate in our hearts. In fish
(two-chambered heart) and amphibians (three-chambered heart), the
oxygenated and deoxygenated blood is allowed to mix in the ventricles,
in mammals and birds (four-chambered heart), the oxygenated and
deoxygenated blood is kept separate. Fish and amphibians are
cold-blooded, meaning that they conform to the temperature of their
environment. Mammals and birds are warm blooded. They maintain a
constant internal temperature, despite the environment. Maintaining a
constant internal temperature allows mammals and birds to carry-out body
processes more efficiently, but it requires more energy. Without
double circulation, the body tissues would not receive enough oxygen to
maintain a constant temperature, and would die.
Double circulation enables the circulatory and respiratory systems in
the human body more efficiently deliver oxygen to the body by separating
oxygen-rich blood ready to deliver oxygen to the body from oxygen-poor
blood that needs to travel through the lungs to absorb ore oxygen before
it can be sent back through the body.
First, oxygen-poor blood is pumped from the heart to the lungs, where it
absorbs oxygen and returns to the heart. The heart then pumps the
oxygen-rich blood to the body, where it delivers oxygen to the cells
that need it. The blood returns to the heart after delivering most of
its oxygen, where it is sent back to the lungs to take up more oxygen.
The cycle repeats with every beat of your heart.
The heart of human beings consist of two sides right and left.
The right side of the heart receives de-oxygenated blood and sends it further for purification to lungs.
The left side of the heart receives oxygenated blood which is pumped
further and sent to all the parts of the body through blood vessels.
This is called double circulation. The energy demands for human beings
is too large and hence it is necessary for the separation of oxygenated
and deoxygenated blood to meet this energy demand.