The Hearts conduction system The electrical impulse responsible

The Hearts conduction system The electrical impulse responsible for stimulating the heart to contract is called the cardiac impulse.

ü To understand the processes involved with the hearts conduction system. ü To recap the phases of the cardiac cycle.

Video… http: //www. youtube. com/watch? v=fz nchh 3 x 54 c

Conduction system ü The heart is myogenic, hence it generates its own electrical impulse. ü The cardiac impulse is initiated from the sinoatrial (SA) node – located in the posterior wall of the right atrium. This is referred to as the pacemaker. ü The impulse travels through both atria and causes them to contract. What is this called?

Ø The impulse activates the AV node in the right atrium, which passes the impulse down the bundle of His, located in the septum of the heart. Ø The bundle of His splits into two branches and spreads the impulse down to the bottom of the heart and then up around the walls of the two ventricles using a network of purkinji fibres causing both ventricles to contract, what is this called? Ø The cycle is then repeated with the next impulse.

Cardiac Cycle. The conduction system initiates the cardiac cycle, which ejects blood from the heart through which arteries? Can you remember how the cardiac cycle works? The stages? How long each stage lasts for?

Task : Prepare a 30 second talk on the conduction system of the heart and the cardiac cycle and how it initiates the cardiac cycle.

Homework. Exam Style Question…. Describe how the conduction system of the heart controls the cardiac cycle. [6 marks]. We will be using this as our starter for Fridays lesson!