Our Sweet heart
Hi friends first of all let’s check the position of our heart. Our heart lies slightly inclined towards left from our middle of our body. The broad area on the top side and sharp portion on bottom. One of third portion on right side and two portions on left. Heart lies as if it is hanging. Our heart is having 250 to 300gram weight. Heart is having a size of our fist. Our heart is having bones on front and back side, lungs on both sides, diaphragm on bottom side. Completely made of muscles, covered with a covering called pericardium.
We can compare our heart with a pump. Truly speaking it is a pump and tank.it has four rooms. Two atrium on top and two ventricles on bottom. The blood which doesn’t contain oxygen and having carbon di oxide will flow through two vena cava and reach up to right atrium. Within less time it will get filled and flow toward right ventricle through valve. This time right atrium will contracts, blood completely flow to right ventricle. Then it will get filled and contracts .the blood flows through pulmonary artery and reaches lungs. From there exchange of gases will occur. The oxygenated blood will flow through four veins and reaches up to left atrium. Left atrium will contracts and will flow through atria ventricular valve and reaches to left ventricle. After filling the left ventricle it contracts, blood flows through aorta. The left and right atriums contracts accurately same time and same as right and left ventricle. The blood from aorta. The top portion of heart is like a pump. Actually it comprises with two pumps. The blood of aorta will reaches up to different cells and exchanges the oxygen with carbon di oxide. That means again a gas exchange. Like this there will be two types of gas an exchange occurs in our body.
In the beginning we referred our heart as a pump. On more analysis we can find that our heart is enough complicated .first of all it is not a single pump but combination of four pumps. There are four tanks. We can compare this as a water purification system.
It is a fact that our heart is under control of our brain .but we can see that our heart is having a special consideration of “autonomy”. Our conscious mind is not having any control on our heart. The working will be controlled by itself. But we can see that somebody condition will affect our heart, like some diseases will stimulates and some will reduces.
Even though the all nerve connection to our heart breaks it will works. Because heart is having autonomy. Our heart will get ready before our brain completely forms in our mothers utrus.thats why we can use the other man’s heart for heart replantation.
The conducting system of heart is very interesting. There are two small nodes. The first node is called Sino-atrial node or SA node. This is on right atrial wall, where aorta starts from there this will spreads as small roots and covers both the atriums.at last it will ends at Atrio-Ventricular node.(AV-node).from AV –node somany roots start as a bundle .it is known as “bundle of his”. This will again split in to two branches. Each one will go to each ventricle. After these, small roots will spread over ventricle muscles.
SA –node has self-stimulating power. Even though heart is not getting any stimulation from outside, heart will produce self-stimulating impulses, seventy two times per minute. The impulse from SA-node passes through nodes and reaches the atrium and stimulates it, and atrium contracts. Blood flows to ventricles.by this time the impulses reach to AV-node. That impulses contracts ventricles and filled blood flows out from ventricle. Again SA-node activates and this cycle will continue till our death. This cycle is calling cardiac cycle.
Do you know what happens when SA-node get any problem? If SA-node gets complaint AV-node will take the action. That time AV-node will act as “pacemaker”. But the rate will decrease. When AV-node gets complaint the roots will take the action. But the rate again reduces.it will call as “heart block”.