The Heart Flashcards
Aorta
Biggest artery transporting oxygenated blood away from the heart
Pulmonary vein
Vein brining deoxygenated blood back to the heart
Which side the the aorta and pulmonary vein on
The left (as if it were your heart)
Atrioventricular valves
One way valves, open when the pressure is higher in the atria than in the ventricles
Semilunar valves
One way valves, open when the pressure is greater in the ventricles than in the blood vessels (above them)
SAN
Sinatrial node, initiates the heart beat, sends electrical impulses across Atri
AVN
Atrioventricular nod, delays electrical impulse, allows atria to conduct, before ventricles contract (empty)
Purkyne fibres
Electrical impulse cause ventricles to contract from the base up
Non conducting tissue
Stops the electi cal impulse from SAN reaching ventricles
How does the SAN control the heart rate
Initiates heart beat, sends electrical impulse across atria, atria contracts, non conducting tissue prevents the impulse reaching the ventricle, AVN delays impulse, AVN sends impulse down bundle of His to purkyne fibres, ventricle contract from base upwards
What does the AVN being delayed allow to happen
Allows atria to contract and empty before the ventricle contract
What occurs in the left ventricle
Highest blood pressure, most cardiac muscle ( contracts with greater force), pumps blood to whole body
Imagine the table- what happens to atria, ventricle, atrioventricular (av) + semilunar (sl) valves during atria systole
Atria= contracted (high bp) ventricle=relaxed (low bp) av= open, sl=closed
What is diastole
When the heart is relaxed
What is systole
When the heart is not relaxed
