Zusammenfassung der Ressource
The heart
- Structure
- Atrium
- Thin-walled
- Pumps short distance -
ventricle
- Elastic
- Stretches as
blood is collected
- Ventricle
- Thick-walled
- Pumps to lungs/whole body
- Aorta
- Connected to LV
- Carries
oxygenated blood
to body
- Vena Cava
- Connected
to right
atrium
- Brings deoxy blood
back from body
- Pulmonary artery
- Connected to
right ventricle
- Deoxy blood from lungs
- Unusual for artery to
carry deoxygenated
- Pulmonary vein
- Connected to
left atrium
- Brings oxygenated
blood from lungs
- Unusual for vein to
carry oxygenated
- Cardiac cycle
- 1) Electrical activity SAN ->
across both atria -> atria contract
- 2) Collagen stops wave
crossing to ventricles
- 3) Wave passes to AVN
- 4) Electrical impulse -> bundle of His
- 5) Wave -> down septum to base of
ventricles, bundle branches into smaller fibres
- 6) wave released from fibres ->
ventricles contract apex up.
- Diastole
- Blood returns to atria
through pulmonary vein & vena cava
- As atria fill, pressure ^ -> AV valves open
- Walls of atria + Ventricles relaxed
- Relaxation of ventricles reduces pressure -
lower than aorta/pulmonary artery
- SL valves close. "Dub"
- Atrial systole
- Atria contracts,
forcing remaining
blood into
ventricles
- thin walls as only to ventricles
- Ventricles relaxed
- Ventricular systole
- Walls contract
simultaneously once
full
- Increases pressure - shuts AV
valves "lub"
- SL open -> blood pushed into pulmonary artery &
aorta
- Thick walls as pump to lungs/body
- Myogenic
- Supplying heart with O2
- Coronary arteries branch off aorta
shortly after leaving heart
- Blockage here leads to
myocardial infarction
- Valves
- Atrioventricular
- between atrium&ventricle
- Prevent backflow when ventricles contract
- Semi-lunar
- In aorta&pulmonary artery
- Prevent backflow when recoil in
aorta/pulmonary artery causes
pressure to exceed that in ventricles
- Cardiac output
- heart rate x stroke volume
- Heart rate
- Rate of heart beat
- Stroke volume
- Vol. blood pumped
out at each beat