The Heart Flashcards
Function of the heart
The heart is a muscular pump, which functions to drive blood around the body
Located within the thorax between the lungs and above the diaphragm
Displaced to left side of chest
Aorta
Carries oxygenated blood from the heart to the body
Vena cava
Carries deoxygenated blood from the body to the heart
Superior vena cava carries blood from head and upper body
Inferior, vena cava carries blood from lower body
Pulmonary artery
Carries deoxygenated blood from the heart to the lungs
Pulmonary vein
Carries oxygenated blood from the lungs to the heart
Pulmonary valve
Regulates blood flow from the left ventricle into the aorta
Mitral valve
Regulates blood flow from the left atrium into the left ventricle
Bicuspid - 2 leaflets
Tricuspid valve
Regulates blood flow from the right atrium into the right ventricle
Tricuspid – three leaflets
Ventricles
Responsible for pumping blood through arteries
Thick, muscular walls
Left ventricle has thicker wall than right because it does more work
The two ventricles are separated by a muscular septum
Atria
Receive incoming blood from veins
Contraction of atria pushes blood into ventricles
Thin walls
Valves prevent blood from ventricles going back into aorta
Valves
Insure blood flows only in One Direction through the heart
Semi-lunar valves – pulmonary valve on a Aortic valve
Atrioventricular valves - mitral valve and tricuspid valve
Veins
Carry blood to the heart
Arteries
Carry blood away from the heart
Arteries
Carry blood away from the heart
Atrial systole begins
Atrial contraction forces a small amount of additional blood into relaxed ventricles
Ventricular systole 1st phase
Ventricular contraction pushes AV valves closed, but does not create enough pressure to open semi lunar valves
Ventricular systole second phase
As ventricular pressure rises and exceeds pressure in the arteries, the semi lunar valves open and blood is ejected 
Ventricular diastole early
As ventricles relax pressure in ventricles, drops and blood flows back against cusps of a semi lunar valves and forces and closed
Blood flows into the relaxed atria
Ventricular diastole late
All chambers are relaxed
Ventricles fill passively
Sino-atrial node (pacemaker)
Located in right atrium
Specialised cardio myocytes with the ability to generate action potentials (electrical impulses)
These impulses are then transmitted to the atrial myocardium and to the atrioventricular node.
Atrio-ventricular node
Located at base of right atrium at the atrioventricular junction
Atria are electrically isolated from ventricles
Function of AV node – delay transmission of impulses until the atria are fully contracted
Simultaneous contraction of atria and ventricles, would lead to backflow
Bundle of his
Function is to transmit the impulse to the apex of the heart, without depolarising, cardio, myocytes en route
Important, that contraction of the ventricles begins at apex, forcing the blood towards the aorta and pulmonary artery
Functions of the blood
Oxygen transported in blood to the body which is bound to haemoglobin in red blood cells
Transports nutrients
Removal of waste products
White blood cells mediate immune system
Hormones transported in blood
Heart beat cycle order
Atrial systole begins
Atrial diastole begins
Ventricular systole stage one then two
Ventricular diastole early phase
Ventricular diastole late phase
