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Physiology 1
heart and lung function
| Term | Definition |
|---|---|
| respiratory centre | area in the brain stem that controls breathing rate and depth |
| pulmonary circulation | blood from the heart to the lungs and back to the heart with oxygen |
| system circulation | oxygenated blood carried from the heart to body tissues and back to the heart. |
| vasoconstriction | reducing flow of blood into capillaries |
| vasodilation | increasing flow of blood into capillaries |
| systolic pressure | pressure of heart contracting |
| diastolic pressure | pressure of the relaxed heart |
| venous return | mechanisms that assist the return of blood to the heart. |
| skeletal muscle pump | muscle action squeezes veins and forces blood towards the heart |
| respiratory pump | breathing movements force blood to flow towards the heart |
| arterio-venous oxygen difference | amount of oxygen removed from the blood by the muscles |
| SAN (sino-arterio node) | small mass of cardiac muscle that generates the heartbeat |
| intrinsic | the idea that the heart generates it's own contraction from within itself |
| myogenic | impulses generated without nervous stimulation |
| AVN (atrio-ventricular node) | bundle of tissue that forms part of the conduction system |
| bundle of His | specialised bundle of nerve tissue that forms part of the conduction system |
| purkinje fibres | specialist nerve fibres found in the ventricles |
| stroke volume | Volume of blood leaving the left ventricle per beat |
| ejection fraction | proportion of blood in left ventricle pumped out each beat |
| cardiac output | Stroke volume x heart rate |
| Starling's law of the heart | the greater the venous return, the greater the strength of contraction |
| chemoreceptors | group of cells sensitive to changes in blood acidity |
| hypertrophy (athletes heart) | the increase in size of the heart that accompanies training |
| bradycardia | the reduction in resting heart rate that accompanies training |