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Overview of CV system
9/28/11 Third Lecture
12
Medical
Graduate
09/28/2011

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Cards

Term
What are the 4 major steps involved in the CV system that ensure all tissues get the blood supply they need?
Definition
1. Generate arterial pressure in the left ventricle
2. Let tissues regulate their own flow
3. Generate enough venous pressure to ensure cardiac filling
4. Maintain blood volume
Term
What are the sections of the vascular system where exchange of nutrients and waste occur called?
Definition
Vascular beds
Term
Which flow system has higher pressure, systematic or pulmonary? Why?
Definition
Systematic has higher pressure. Both circuits have the same flow, so this occurs because the pulmonary blood circuit has lower resistance
Term
Where does the largest pressure drop occur in systemic blood flow?
Definition
Arterioles, as they have the most resistance of the systemic blood flow circuit.
Term
Explain why arterioles have a higher pressure drop then capillaries if capillaries have higher resistance then arterioles.
Definition
Capillaries exist in large numbers and in parallel, so the combined resistance of them tends to make the net resistance of the capillary bed less then that or the arterioles feeding it.
Term
Define total peripheral resitance
Definition
The total resistance to flow between the aortic valve and the right atrium
Term
What two equations can be used to get total cardiac output?
Definition
1. beats per minute x stroke volume

2. (mean arterial pressure)/(total pulmonary resistance)
Term
What measurement reflects blood vessels response to transmural pressure?
Definition
Compliance. C= (change in volume)/(transmural pressure difference)
Term
Which has higher compliance and why: Arteries or Veins?
Definition
Veins.

1. Arteries have thick, strong walls that resist volume changes
2. Veins need to be able to alter compliance to maintain constant pressure when facing volume changes
Term
What is the key variable used to control arteriole blood flow?
Definition
Resistance
Term
What is the key variable used to control veinous blood flow?
Definition
Volume and compliance
Term
Explain how altering venous compliance can alter pressure
Definition
Reduction in compliance (more elastic recoil on the vessel) squeezes the blood and raises venous pressure
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