Question

Short essay: Describe the pattern of electrical activity (i.e. the spread of electrical activity) that occurs in the heart during a normal heartbeat cycle. Do NOT discuss the particular channels or ions involved in changing membrane potentials or the mechanical results of these action potentials.

Answer 1

The human heart is a muscle made up of tiny cells which are capable of transmitting electrical signals that controls the heartbeat and their timing. Thee are pathways through which these signals are capable of being transmitted throughout the heart.

The signals originate from Sinoatrial/SA node, which is a clump of cells at the top of your heart. This signal travels down, triggering the Atria, making them contract which pushes the blood down the ventricles. Once the blood is in the ventricles, the signal reaches a bunch of cells at the bottom of your heart known as atrioventricular/AV node. They slow down the signal momentarily for the ventricle to have enough time to receive the blood from the auricles. The signal then triggers the ventricles. It does so by going through the "Bundle of His" which forks into two branches, stimulating each one of the ventricle. The branches further forms conducting fibres, which transmits the signals all over the ventricles. When they contract, the right one pumps the blood into the lungs and the left ventricle pumps it into Aorta which takes it to the rest of the body.

Hope this helps. It was electrifying to be able to answer this one!