Integration of Cardiovascular Mechanisms Flashcards
What are the three factors affecting SV?
Pre-load
Myocardial Contractility
After-load
MAP=
CO x SVR
or
DBP + 1/3 Pulse Pressure
CO=
HR x SV
What is SVR regulated by?
Regulated by vascular smooth muscle
What is the result of vasoconstriction in SVR?
Increased SVR and MAP upstream
What is the result of vasodilatation in SVR?
Decreased SVR and MAP
What is resistance to blood flow directly proportional to?
Blood Viscosity
and
Length of blood vessels
What is resistance to blood flow inversely proportional to?
Radius of blood vessels to the power of 4
What is the biggest influence on resistance to blood flow?
Radius of blood vessels
What are the factors responsible for extrinsic control of VSM?
Nerves and Hormones
Baroreceptor reflex
What are VSM supplied by?
What is the neurotransmitter?
What does it act upon?
Sympathetic supply
Noradrenaline
alpha receptors
What is vasomotor tone?
partial constriction due to continuous release of noradrenaline at rest
What does the hormone adrenaline act upon?
Organ specific
alpha receptors and b receptors
Where are alpha receptors dominant?
Skin, gut, kidneys
Where are B receptors dominant?
Cardiac muscle and skeletal muscle