Heart Flashcards
Parts of the heart
Superior/ inferior vena cava Pulmonary artery/ vein Aorta Left/ right atrium Left/ right ventricles Bicuspid/ tricuspid valves Semilunar valves Chordae tendinae Papillary muscle Fibrous pericardium Septum Apex Cardiac muscle
Which side of the heart is larger and why?
Left, has to pump blood around the body
Function of valves
Prevent backflow of blood
Structures involved in cardiac cycle
Sinoatrial node
Atrioventricular node
Bundle of His
Purkinje fibres
Double circulatory system
Blood passes through heart twice
Due to the fact that blood has to pass through tiny caps
BP in lungs
Lower, blood movement is very slow, time for oxygen to diffuse into caps
BP in heart
Raised, so it can travel around the body
Coronary arteries
Supply heart with blood and oxygen
Blockage of coronary arteries
Myocardial infarction, deprive heart of blood, oxygen, respire anerobically, lactic acid produced, cells die
Circulatory problem
Irregular electrical impulses
Cardiac arrest, electrical event, life threatening
Cardiac cycle
SA node
Elec impulse from vagus nerve, spreads through atrial walls, atrial systole
Atrial pressure>Ventricular pressure
Blood forced into ventricles
Cardiac cycle
AV node, Bundle of His, Purkinje fibres
Delay of electrical signal gives time for atrial contractions before ventricles
Fibre pathway sends impulses to muscular ventricular walls, causes contractions from apex
AV valves forced shut, ventricular pressure>aorta, pul art pressure
SL open, ventricular systole
Cardiac cycle
Break
Atria fill will blood vena cava and pul veins, pressure increases
Atrial pressure>ventricular pressure,, AV valves open, SL valves close
Atrial and ventricular diastole
How to change heart rate
Changes in pH of blood, detected by chemo receptors in aorta, carotid
Signal sent to medulla in brain stem
Vagus nerve signals to SAN
SAN slows down rate of firing
Sympathetic nerve causes SAN to fire more rapidly
