What are the functions of the CVS?
Rapid distribution of nutrients, H2O, electrolytes & hormones • Rapid removal of waste products • Production of interstitial fluid • Infrastructure of the immune system • Temperature regulation
What is endocarditis?
infection to the valves, ageing
What is the annulus fibrosis? what sits here?
fibrous layer between the atria and ventricles
AV valves
what is the apex beat?
furthest away from the sternum where the heartbeat can be felt
what percentage of the blood does the venous system hold?
70%
what is physiological splitting?
when the s2 sound is split into two sounds
What is the windkessel effect?
elastic recoil of the heart - when the arteries behave as an elastic reservoir.
What type of arteries are muscular arteries? examples?
distributing, brachial and radial arteries
do the muscles distend or relax when pressure rises?
distend
what are the properties of arterioles?
diameter?
Microscopic vessels
(
What receptors stimulate vasoconstriction and vasodilation?
Vasoconstriction
– Generally, α adrenoceptor stimulation
• Vasodilatation
– In some blood vessels β receptors dominate and stimulation
produces vasodilation e.g. skeletal or coronary circulation
What type of vessels are capillaries and what is the diameter?
exchange vessels, ~7µm diameter
What type of vessels are venules? diameter? do they contain smooth muscle? effect?
Luminal diameter
Can the veins be innervated by the sympathetic nervous system?
yes but not to the same extent as arteries
Why does a small change in blood volume in the veins have such a large impact on the body?
capacitance vessels., hold greater blood volume
Venoconstriction?
they constriction than arterioles but greater blood volume
What is CO equal to?
CO = MABP/TPR
What needs to vary to determine blood flow?
resistance
What is the largest contribution to total resistance?
arterioles
is total resistance less than or more individual resistances?
less than
Why does change in blood flow in one organ not effect the other organs?
they all flow at different times
How is flow through a vascular bed determined?
via resistance
what is poiseulles law?
R = 8hL / πr4
what happens to velocity when CS area increases?
decreases
Why does blood pressure stay low in veins?
capacitance vessels, behave as an elastic reservoir