Cardiovascular system Flashcards
What is cardiac output?
CO or Q. Amount of blood ejected by each ventricle in one minute (ml/min). Stroke volume X heart rate.
What is stroke volume?
The volume of blood pumped out by one ventricle in one beat (ml/beat).
What is preload?
The volume of blood entering the ventricles.
What is the EDV?
End-diastolic volume. The amount of blood in ventricles before the ventricles strat contracting.
What are the factors that can increase preload?
Hypervolemia, valve regurgitation, heart failure.
What is the Frank-Starling law of the heart?
The amount of blood entering the ventricles will be the same as the amount of blood exiting the ventricles.
What is inotropy?
Contractility = how hard the myocardium contracts for a given preload.
Of what factors does the inotropy depend on to?
The integrity of the myocardial fibre and the availability of Ca2+.
What is afterload?
The resistance the ventricles must overcome in order to circulate blood. Mainly aortic pressure. (so all the pressure the contraction of ventricles must “win” to send blood out and open valves).
What happens to the stroke volume is afterload increases and preload stays the same?
Stroke volume decreases, because it is harder to eject blood out of the ventricle.
Which factors increase afterload?
Atherosclerosis (narrowing of vessels) and hypertension (high blood pressure).
What is cardiovascular centre?
Part of the brain (in medulla oblongata) that is resonsible for regulating heart rate through the nervous and endocrine systems.
What are chemoreceptors?
Receptors that detect the O2, CO2, H+ levels in blood.
What are baroreceptors?
Receptors that detect arterial pressure of blood.
What is ECG?
The record of the potential differences that originate in cardiac muscle cells as a result of the appearance of action potentials associated with heart contraction.
