GUMES CV Flashcards
what are the layers of the pericardium
fibrous
parietal
parietal cavity
visceral
what attaches the free edges of the valves to the papillary muscle
chordae tendinae
what are the korotkoff sounds
sounds of blood flow, one is systole and the second is diastolic
what is the interventricular septum
the wall of tissue that separates the right and elft ventricles of the heart
what is atrial septal defect
the absence of a septum between the atria leading to mixing of oxygenated and deoxygenated blood
what is ventricular septal defect
defect in the ventricular septum leading to blood flow between the ventricles under pressure
what is atrioventricular septal defect
birth defect whcih leads to holes between the chambers of the heart
can also mean the valves that control the blood flow between these chambers may not be formed correctly
describe artery structure
thick outer wall
small lumen
thick layer of muscle and elastic fibres
describe capillary structure
very small lumen and wall made of a single layer of cells
describe vein structure
thin layer of muscle and elastic fibres, large lumen and fairly thin outer wall
what is found in arteriole walls
muscle
elastic fibre
fibrous tissue
how does the lumen of arteries vary
increases as a pulse of blood passes through
why are the walls of arteries strong and elastic
to withstand the pulsing of the blood and prevent bursting.
maintain high blood pressure and prevent blood flowing backward
what is the function of capillaries
supply all the cells with their requirements and take away waste products
describe the wall of capillaries
one cell thick
how wide is the lumen of a capillary
enough for a singel red blood cell to pass through
why do capillaries not need strong walls
most of the blood pressure has been lost
what can pass through the cells of capillary walls
white blood cells
why do capillaries have narrow lumens and thin walls
to bring blood into close contact with body tissue and allow diffusion of materials between the two
describe the pressure of blood as it returns to the heart
low
describe the walls of veins
thin
mainly fibrous
less muscle and elastic tissue than arteries
why is there a wide lumen on veins
offers less resistance to blood flow
where is the AV node
centre almost
what are the AV bundles
stretch down from the AV node to provide action potential to the myocardium