Lecture 7&8 Cardiac Output, resistance and flow blood pressure Part 1 Flashcards
What is Heart Rate?
(HR) The number of contractions per minute
What is Stroke volume?
Stroke volume or SV is the volume of blood ejected per contraction
What is Cardiac output
Cardiac Output (CO) is the volume of blood pumped out of the left ventricle (right ventricle) per minute
What is Venous Return?
The volume of blood returning to the heart right or left ventricle per minute
What does this equation mean? CO = HR x SV
Cardiac output(l/min) = Heart Rate(Beats/min) times Stroke Volume (ml/beat). The answer will be in ml (1000ml) and will need to be converted to Litres (1L)
True or false? Sympathetic activation increases HR
True
True or false? Sympathetic activation decreases HR
False
True or false? parasympathetic activation increases HR
False
True or false? parasympathetic activation decreases HR
True
Hormones such as adrenaline or noradrenaline act on adrenergic receptors (Beta receptors) from the parasympathetic or sympathetic?
sympathetic
What is the difference between alpha and beta receptors?
Beta receptors are on the heart, alpha receptors are in the arteries or veins
What are the three ways we can increase stroke volume?
Increase pre-load (end diastolic volume) decrease after-load (aortic blood pressure) Increasing contractility
Pre-load is defined as what?
The degree of stretch of the ventricular wall prior to contraction.
For practical purposes, what is measured as a ventricular end-diastolic volume?
Pre-load
After-load is defined as what?
the pressure that the ventricles must overcome to eject blood.