The heart is located in the thoracic cavity, and acts as a pump. Blood comes to it through a series of wide vessels or veins. At each pump, the blood is cycled through two separate circulations. At first, the oxygen-deprived blood arriving from the system is cycled through the lungs where gas exchanges take place. Carbon dioxide, collected in its journey through the system, is then excreted, to be exhaled with the next breath. In its place, oxygen is taken aboard by the blood, converting it into rich, red blood.
At the next beat, this blood returns to the heart, again to be pumped out HO through the large artery called the aorta to circulate to all parts of the body. When this has been completed, it is again collected via the vein or venous system, to be rechanneled into the heart once more.
This process goes on tirelessly, non-stop year in, year out, for the remainder of the person’s life.
The heart is a large muscle, and its fibers are all interconnected. In there are two chambers on either side. The smaller upper ones are called the atria; the large lower ones are called the ventricles. Both are connected to tubes or vessels, and access is through an intricate system of valves that continually open, then snap shut with the heartbeats.
Blood comes first to the right atrium, then through a valve to the right ventricle. Next it goes via the pulmonary zing) artery to the lungs to be reoxygenated. From here it returns through the pulmonary vein to the left atrium, then through a valve to the left ventricle. This is a massive organ, and when this contracts, it must give the blood sufficient momentum to force its way into a large tube, the aorta, and circulate blood around the system. Imagine the amount of force and strength needed to sieve this.
Don’t you think it’s incredible that babies are born with the heart intact so often and that it’s relatively disease-free for such a long time, especially when so many other dreadful things may occur to them? Considering the number of ailments that the average child gets, it really is surprising that the heart escapes from so much.