CVPR Week 2: CV system and Hemodynamics Flashcards
Objectives

Components of the Cardiovascular system

The circuitry of the cardiovascular system

Arteries carry…
blood from the heart to the capillaries

Veins carry…
blood from the capillaries back to the heart

Structural relationships of blood vessels

Large arteries properties
- conduit vessels: conduct blood under high pressure to tissues
- Highly elastic

Elastic recoil of arterial walls
Compliance = Δ volume
Δ pressure
Maintains relatively constant flow during the entire cardiac cycle
the arteries expand during systole and then recoil during diastole acting as a secondary pump to keep flow constant during diastole

Compliance equation
Compliance = Δ volume
Δ pressure
Elastic recoil of arterial walls: Rigid arteries
compliance would be 0

Compliant vs rigid flow: why is constant flow through the capillaries important?
rigid vs compliant arteries
constant flow is important because
- to have constant perfusion to the tissues and nutrient/waste exchange

Small arteries and arterioles properties
- large proportion of vascular smooth muscle
- highly innervated (almost exclusively by the sympathetics)
- “Resistance vessels”

Small arteries and arterioles AKA
Resistance vessels because they can provide the most resistance of any other segment
Properties of veins
- conduct blood under low pressure back to the heart
- thin walled
- can contract because they have a little smooth muscle
- sometimes they are innervated as well
- “capacitance vessels” because they are a volume reservoir
Veins AKA
Capacitance vessels
Blood volume distribution
~2/3 in the veins
16% in arteries

How veins regulate blood volume distribution

- veins constrict
- can drive a venous return
- usually doesn’t return to capillaries because of a small pressure gradient
- ↑ Venous Return in response to sympathetic nerve activity to veins to constrict
- An ↑ venous return results in ↑ cardiac output and ↑ Mean arterial blood pressure

An ↑ venous return results in
↑ cardiac output and ↑ Mean arterial blood pressure
pressure characteristics of the systemic circulation
- The systemic mean arterial pressure is about 100 mmHg for just about every animal
- The pulmonary mean arterial pressure is about 15 mmHg

The mean pulmonary arterial pressure is?
About 15 mmHg
The mean systemic arterial pressure is
about 100 mmHg for just about every animal
pulmonary pressure gradient
15 - 5 = 10 mmHg

Systemic pressure gradient
100 - 2 = 98 mmHg

Pulse Pressure equation
systolic - diastolic = pulse pressure


































