How the heart grows

The heart is such a remarkable organ that perhaps a few words about how it develops and grows are in order.Within the first two weeks after conception a small tube begins to form in the tiny embryo or unborn baby. Believe it or not,this is the forerunner of all the blood-vessels in the body.A few embryonic blood cells also begin to float around within this tiny vessel.This is the beginning of the blood stream.From these early developments the entire circulatory system of the body will eventually form.

As the little tube expands and grows,it begins to twist in a certain way,forming at first just one single chamber.This is the beginning of the heart! With this enlarging area a septum or dividing wall begins to grow, forming not one but four chambers.The two upper chambers are the left and right atria(or auricles);the two lower ,the left and right ventricles.Normally there is no connection between the right and left sides of the heart after birth.But special doors or valves open between the atrium and ventricle on each side of the heart,so that the blood will flow in only one direction.This whole mechanism is surprising simple,considering the enormous amount of work the embryonic heart must do.Any failure in the development of the septum or valves may lead to some form of congenital heart disease


Circulation before birth

During foetal life there is no connection between the baby's blood stream that of his mother.all the blood flowing through the baby's heart is always his own,never his mother's.Her blood circulation is entirely separate.However,the baby's blood stream flows close to the mother's-being divided by a very fine living membrane-so that he can pick up food materials and oxygen necessary for his own growth,and at the same time get rid of the materials he no longer needs.

As the tiny unborn baby grows,so does his heart.The most critical time of growth is during the first three months of pregnancy if at that time his mother should come down with some virus infection,such s German measles,the baby's heart may be deformed by some type of congenital heart disease.

Doctors recongnixe four maor types of heart disease:congenital heart disease,rheumatic heart disease,hypertensive heart disease,and coronary artery disease.Ln addition,there are several minor problems.