Overview of the function of the cardiovascular system Flashcards Preview

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Flashcards in Overview of the function of the cardiovascular system Deck (14):
1

Function of the CVS

- Bulk flow system: O2 and CO2, nutrients, metabolites, hormones, heat.
- Is amazingly reliable: over 2.5 billion beats in 70 years.
- Is remarkable flexible: pump can vary output, vessels can redirect blood, vessels can store blood.

2

How are pumps arranged in the CVS?

Pumps are in series
- Therefore output must be equal

3

How are most vascular beds arranged in the CVS?

Most vascuar beds are in parallel.
Therefore
- All tissues get oxygenated blood
- Allows regional redirection of blood
- Exceptions prove the rule

4

What is the cardiac output and oxygen consumption in the heart at rest?

Cardiac output = 4%
Oxygen consumption = 10%

5

What is the flow at rest of blood in the heart?

215 ml/min

6

What is the overall resting cardiac output?

5000 ml/min

7

What is the pressure difference equal to?

Pressure difference = mean arterial pressure - central venous pressure

-Affects all tissues

8

How is flow calculated (equation)?

Change in pressure/Resistance

- Controlled by radius^4
- Selectively redirects flow

9

What structures act as "the taps" controlling resistance (and flow) to each vascular bed?

Arterioles

10

Features of the Aorta

Elastic arteries = aorta
- wide lumen, elastic wall
- damp pressure variations

11

Features of arteries

Muscular arteries = other arteries
- wide lumen, strong non-elastic wall
- low resistance conduit

12

Features of arterioles

Resistance vessels = arterioles
- narrow lumen, thick contractile wall
- control resistance & therefore flow
- allow regional redirection of blood

13

Features of capillaries

Exchange vessels = capillaries
- narrow lumen, thin wall

14

Features of venules and veins

Capacitance vessels = venules & veins
- wide lumen, distensible wall
- low resistance conduit, & reservoir
- Allows fractional distribution of blood between veins & rest of circulation (esp. heart)