D3 - Nervous control of cardiac cycle

• the process of the heart filling with blood and then contracting

• electricity

• sinoatrial node (SAN) atrioventricular node (AVN) • bundle of his and purkinje fibres

• the pacemaker • found in the walls of the right atrium • sends electrical impulses from the right atrium through the walls of the atria, causing muscular walls to contract • contraction forces blood through valves to ventricles

• located in the center of the heart between the atria and ventricles • acts as a buffer to slow down electrical signal from the SA node • this allows the atria to contract before the ventricles contract (ventricles relaxed and receive blood)

• specialised heart muscle cells that are responsible for transporting the impulses from the AV node • found in the walls of ventricles and septum • ends of these BOH are thin filaments called PF • these allow the ventricles to contract at a paced interval • ventricular contraction causes blood to be pushed out through the valves into the arteries

• regulates body function & involuntary movements (breathing and heart beat) • can be divided into the sympathetic and parasympathetic nervous system

• prepares body for intense physical activity (referred to as ‘fight or flight’ response) • cause heart to beat faster and lungs to ‘work harder’ (increase in tidal volume) = creates more energy

• relaxes body and slows energy function (known as the ‘rest and recovery’ response) • after exercise your heart rate will need to slow down to it’s normal resting level, PNS slows heart rate as a result