THE heart is one of the most important organs in the human body.
It is the pump that keeps blood moving around the body, beating approximately 72 times per minute.
The heart pumps the blood, which carries all the oxygen and vital materials which help our bodies function and removes the waste products that we do not need.
For example, the brain requires oxygen and glucose, which, if not received continuously, will cause a person to lose consciousness.
Inside the heart there are four chambers — two on the left side and two on the right.
The two small upper chambers are called the atria, while the two larger lower chambers are called the ventricles. The four valves in the heart act like gates that open and close, making sure the blood travels in one direction through the heart — like a one-way traffic system. Chris Mulryan, senior lecturer at the University of Bolton, explains: “The best way to think about the heart is that it’s two pumps in one.”
As the heart muscle contracts, it pushes blood through your heart.
With each contraction — one heartbeat — the heart pumps blood forward from its left side, through the aorta (the main artery leaving the heart) and into the arteries.
Blood from the right side is pumped to your lungs, via the pulmonary artery. After the contraction, the blood continues through the arteries, which divide off into smaller branches of microscopic capillaries to the rest of the body.
The blood then travels back to the heart from the capillaries into the veins. The branches of the veins join to form larger veins, which deliver the blood back to the right side of the heart.
As the heart relaxes in between each heartbeat, blood from the veins fills the right side of the heart and blood from the lungs fills the left side of the heart.
A cardiac arrest happens when the heart stops pumping blood around the body and goes into ventricular fibrillation.
Mr Mulryan, who trains nurses in the clinical simulation suite at the university, said: “The main causes are either that the heart cannot do anything or pump anything at all or that there is a problem with blood pressure in the chest, or an abnormal heart rhythm.
“In this case, it can either go soft like a jelly or stand still altogether. Or that there has been a large loss of blood.” Cardiac arrest can quickly result in death if not treated very quickly. Cardio-pulmonary resuscitation (CPR) can help keep blood moving temporarily, but a defibrillator is needed to restart the heart.