week 7 - HEART Flashcards
AV valves
close: ventricles contract AP<VP
open: ventricles relax AP>VP
- anchored by chordae tendinae to papillary muscles
SL valves
close: ventricles relax AP>VP
open: ventricles contract AP<VP
coronary circulation 1
L and R coronary arteries arise from base of aorta
coronary circulation 2
L coronary artery gives rise to the anterior ventricular artery and R coronary artery gives rise to the posterior interventricular artery
coronary circulation 3
anterior interventricular artery supplies oxygenated blood to the anterior ventricles and the posterior interventricular artery supplies oxygenated blood to posterior ventricles
coronary circulation 4
middle cardiac vein drains blood from the posterior ventricles to the coronary sinus and the great cardiac vein drains venous blood to coronary sinus - returns to the right atrium
blood pathway 1
blood enters the right atrium from the superior and inferior vena cava
blood pathway 2
blood moves to the right ventricle through the tricuspid valve
blood pathway 3
blood leaves the right ventricle via the pulmonary semilunar valve and moves into the pulmonary trunk
blood pathway 4
pulmonary trunk divides into left and right pulmonary arteries that take blood to the lungs - carbon dioxide is taken out and oxygen is put into blood
blood pathway 5
blood returns to the heart via pulmonary veins to the left atrium
blood pathway 6
blood moves from left atrium into left ventricle through aortic valve/mitral valve
blood pathway 7
blood leaves the left ventricle via the aortic semilunar valve and moves into the aorta where it is distributed around the body
phase one cardiac cycle - ventricular filling
atria: relaxed then contracted
ventricles: relaxed
chamber: atria P>ventricular P
AV valves: Open
VP/AP: ventricular P<arterial P
SL valves: closed
blood movement: atria - ventricles
phase 2a cardiac cycle - isovolumetric contraction
atria: relaxed
ventricles: beginning to relax
chamber: VP>AP
AV valves: closed
VP/AP: VP<AP
SL valves: closed
blood movement: none (isovolumetric)
phase 2b cardiac cycle - ventricular ejection
atria: relaxed (diastole)
ventricles: contraction
chamber: VP>AP
AV valves: closed
VP/AP: VP>AP
SL valves: Open
blood movement: ventricles - arteries
phase 3 cardiac cycle - isometric relaxation
atria: relaxed
ventricles: beginning to relax
chamber: ventricular P>arterial P
AV valves: closed
VP/AP: ventricular P<arterial P
SL valves: closed
blood movement: none
intrinsic innervation
parasympathetic activity - myocardium is able to stimulate its own contraction - formed by pacemaker cells
1. sinoatrial node
2. Atrioventricular node
3. Atrioventricular bundle
4. Bundle branches
5. Purkinje fibres
extrinsic innervation
autonomic NS - modifies myocardial activity (otherwise HR is always 100bpm - set by SA node)
- Cardioacceleratory (cardiostimulatory) centre increases BOTH heart rate and force of contraction
- Cardioinhibitory centre decreases heart rate ONLY
cardiac output
stroke volume x heart rate - volume of blood pumped by the left or right ventricle in one minute
factors that effect cardiac output
- SV: volume of blood ejected from L or R ventricle per peat
- HR
- EDV + ESV + preload (volume of blood after diastole before systole)
venous return
amount of blood returning to the heart from systemic or pulmonary circuits
contactility
amount of force produced by myocardial contraction
= higher SV (lower ESV) - higher CO
bradycardia
heart rate is slower than normal >60bpm
