How does the heart pump blood around the body?

Firstly it is very important to understand the basic anatomy of the heart, so I would ensure all students would be able to visulise and draw the structure of the heart and are capable of labelling the pathway that both oxygenated and deoygenated blood takes. I would explain the basics of systole and diastole and the pressure differences that occur in each chamber. The heart is a very important and tricky topic, so I would help students understand how the heart functions while drilling in vocabulary and key words that examiners look for while marking questions. I would also help students formulate answers to past exam questions using these key words.

The hearts rhythmical electrical activity is the reason the heart can pump blood constantly around our bodies. The source of this electrical activity is a network of specialised cardiac muscle fibres called autorhythmic fibres. They act as a pacemaker, setting the rhythm of electrical excitation which causes the contraction of the heart. The bundles of autorhythmic fibres form the cardiac conduction system, which consists of the Sinoatrial node (SAN), Atrioventricular node (AVN), the Bundle of His and the Purkinji fibres. Excitation begins with the SAN which is located in the wall of the right atrium. The SAN sends electrical impulses across the wall of the right atrium causing it to depolarise and contract, forcing blood down into the right ventricle. Next the electrical activity passes to the AVN, here the electrical impulse is delayed slightly before stimulating the Bundle of His so to ensure all blood has left the atria. Once the atria have fully contracted the electrical current propagates through the Bundle of His and the action potential enters both the right and left branches. Finally electrical impulses reach the Purkinji fibers which spread through and cause depolarisation of the ventricles causing them to contract and force blood into the pulmonary artery and the aorta respectively. The blood then continues on its journey depending either to the lungs to collect oxygen or to the head and body to deliever oxygen.