Cardiovascular system basics- anatomy and physiology Flashcards
What does the fibrous atrioventricular ring do?
supports valves
no electrical conduction
What is systole?
contraction- heart ejects
What is diastole?
relaxation- heart fills
What are the characteristics of a cardiac action potential?
Plateau long refractory period prevents tetany- (caused by lack of calcium) prevents arrhythmias allows heart to fill
All cardiac cells have…..?
inherent rhythmicity
Why does the heart generate it’s own electrical activity or action potential?
slow influx (leak) of Na ions to reach threshold
What happens when the SA node fails?
AV node takes over the pacemaker role?
What is the pathway of the cardiac action potential?
SA node Spreads across atria AV node Spread down bundle of his right and left bundle branches arrives at apex purkinje fibres
What is cardiac output?
amount of blood ejected by the heart PER MINUTE
How do you calculate heart rate?
beats per minute
What is stroke volume?
amount of blood ejected by the heart per BEAT OR STROKE
How do you calculate cardiac output?
heart rate x stroke volume
What makes the heart beat harder (contractility)?
the more you stretch the heart the harder it contracts, therefore by filling it with blood
What is the left ventricular end diastolic volume (LVEDV)?
Measure of venous return or filling of the heart
What pushes you along the Starling curve?
What makes you jump to a higher starling curve?
venous return
adrenaline
