HEALTHY HEART AND CIRCULATORY SYSTEM

So for starters your heart is approximately the size of your clenched fist and weighs around one pound (less than half a kilogram). It is situated slightly behind and to the left of your breastbone and pumps about 5 quarts of blood every minute which is equal to 75 gallons of blood every hour which is 50 million gallons of blood being pumped in an average lifetime. The pumping of blood is the job of the heart. This transports oxygen and nourishment to all the cells in the body, and returns with wastes and oxygen poor blood. The blood starts by coming in the superior and inferior vena cavas. It then goes into the right atrium and then it flows in the pulmonary artery to lungs, where the gas exchange process takes place. From there it continues on its journey returning through the pulmonary vein into the left atrium to the left ventricle and then flows through the aorta which leads to the rest of the body. There is a muscle wall, septum, which separates the heart into two sections, left, and right. From there the heart is divided horizontally creating two more chambers; therefore having a left atrium, right atrium, left ventricle and right ventricle. Between each chamber is a valve that ensures that blood flows only one way.


WHAT MAKES A HEART BEAT?

Everyones heart has its own electrical system, which is made up of a group of special tissues that travel along the pathways of the heart.

The first group is the SA (sinoatrial) or sinus node. The SA node is a collection of special tissues in the top right upper chamber of the heart, the right atrium, which makes up the hearts natural pacemaker. The SA node sends electrical signals that cause the atria to contract which intern pumps blood into the ventricles.

The second group is the AV (artioventriular) node. The AV node is a structure that sends electrical signals from the right atrium to ventricles.

The conduction of pathways is just a set of pathways that conduct the electrical signals through the ventricles and then pump blood out of the heart to rest of body.