ECG - Anatomy and Physiology Recap

Contrition of the heart is know as ..

Systole - Blood pushed out of the heart

Relaxation of the hearth is know as ..

Diastole - Chambers fill with blood

Contraction of the heart occurs due to ..

Electrical activity in the cardiac muscle cells

Specialised areas of cells within the heart control the rate in which the heart contracts, also known as ..

Pacemakers

No heartbreak

Asystole

Sinoatrial Node

• Generates regular impulses leading to depolarisation

• Begins the heartbeat

• Initiates a wave of contraction in the atria (R to L)

Atrioventricular Node

• Electrical impulses from SAN passes through to the AVN

• Impulse travels down interventricular septum in the bundle of His

• Impulse distributed to ventricles via the Purkinje fibres

• Ventricles contract

SA node

• Lies within the wall of the RA atrium near the opening of the cranial vena cava

• Also known as the ‘pacemaker’

• Causes emptying of the atria and filling of the ventricles

AV node

• Lies within the wall of the atrial septum

• The AV node briefly slows down the electrical signal to allow the ventricles time to receive the blood from the atria

• Impulse pushes blood into the pulmonary arteries and aorta

• When the ventricles contract, the right ventricle pumps blood to the lungs and the left ventricle pumps blood up through the aorta and to the rest of the body