The Heart Flashcards
Definition of the cardiac cycle
The sequence of events required in one successful heart beat (0.8 seconds)
Diastole:
Relaxing
Systole:
Contracting
What is atrial systole:
Atria contracts which forces blood into the ventricles
Definition of myogenic:
Ability to generate its own electrical impulse, causes cardiac muscle to contract
What is the aim of the cardiac conduction system?
Pass the electrical impulses through the cardiac muscle, forcing the atria and ventricles to contract
What are the 5 structures involved in the Cardiac Conduction Cycle?
SA Node AV Node Bundle of His Bundle Branches Purkinje Fibres
Describe the role of the SA (Sino-Atrial) Node and where it is located
Generates the electrical impulse, causes atria walls to contract
Known as the ‘pacemaker’
Located in the wall of the Right Atrium
Describe the role of the AV (Atrio-Ventricular) Node
Collects the impulse from the SA Node and delays it by 0.1 second to allow the atrium to finish contracting before sending it to the Bundle of His
Describe the role of the Bundle of His
Splits the impulse in two in order to distribute it to the ventricles
Located in the septum (separates left and right of heart)
Describe the role of the Bundle branches
Carry the the impulse around the walls and to the base of each of the ventricles
Describe the role of the Purkinje Fibres
Distribute impulses through the ventricle walls, causing them to contract
Name each stage (6) on the path of blood from the body to the lungs
Deoxygenated blood
Vena Cava -> Right Atrium -> (Tricuspid Valve) -> Right Ventricle -> (Semi-lunar valve) -> Pulmonary Artery
Name each stage (6) on the path of blood from the lungs back to the body
Oxygenated blood
Pulmonary Vein -> Left Atrium -> (Bicuspid Valve) -> Left Ventricle -> (Semi-lunar valve) -> Aorta
Define stroke volume (with units)
The volume of blood leaving the left ventricle during each cardiac cycle (ml)