CVS physiology Flashcards
Explain the cardiac cycle and the different stages in detail
What is part of the cardiac cycle is eliminated when heart rate increases for exercise?
Slow filling and slow ejection
Explain calcium induced calcium release?
Explain cardiac muscle relaxation (referring to the calcium reuptake).
What mechanisms of sympathetic stimulation of the heart makes it more contractile
Explain starlings law?
How does this compare to contractility?
What happens to the starling curve with myocardial infarction?
What compensatory mechanims ensue.
Explain the SA node membrane potential cycle
What causes the heart rate to differ from the pacemaker natural depolarisation rate?
Explain the excitation system (the flow from start to end).
What are the speeds through each of the systems?
Myocardium
- Contains gap junctions which pass electrical signal via the intercalated discs, this causes a functional syncytium.
- Conduction through atria 0.5m/s, AV node 0.05m/s, bundle of his, bundle branches and purkinje fibres 5m/s, ventricle muscle 0.5m/s.
Ventricular muscle cell action potential.
Explain each of the phases.
Explain why it is important that electrical and mechanical activity overlap
What is the law of resistance and what vessels is it important with?
Why are hardened arteries bad?
Explain this storage of energy in normal arteries?
What are the different intrinsic and extrinsic controls to vascular tone?
What is reactive vs active hyperemia?
What are the paracrine systems? give examples
Explain the extrinsic nervous system control of venous pressure?
Hormonal extrinsic control of vasculature?
What are the 3 classes of capillaries?
What are the two main functions of capillaries?
Explain each
Explain starlings equilibrium
Using starlings equilibrium explain what would happen with an inflammatory response and during a haemorrhage
What do each of the coronary arteries supply?
Explain the blood supply to the heart during systole and diastole. What happens during exercise? How is this regulated?
Explain cerebral circulation and how it is regulated?
Explain the blood flow to the skin? What is the main purpose?
Explain blood flow to the kidney. How is it regulated?
Explain the regulation of splanchnic blood flow?
How much oxygen does the heart have to extract from the blood that it gets?
What is the major stimuli for increasing blood flow to the heart?
How much stenosis must occur before symptoms occur in the heart?
Why can severe stenosis lead to a downward spiral of symptoms?
Explain the spread of extracellular K+ and its effects on an ischemic heart?
What would you see on an ECG with and STEMI and why?
What happens on the starling curve with cardiac failure?
How is this compensated for?
What is ejection fraction and how does this differ with heart failure? Plus exercise?
Cardiovascular variables, comparison of normal heart vs with heart failure. How does this change with exercise?
What are the two main compensations that occur with cardiac failure?
Why does oedema occur with heart failure?
Peripheral vs pulmonary
Law of Laplace. How does this relate to heart failure?
Problems facing the failing heart?
How do you treat heart failure?
