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)
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1
Q

Function of the CVS

A
  • 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
Q

How are pumps arranged in the CVS?

A

Pumps are in series

- Therefore output must be equal

3
Q

How are most vascular beds arranged in the CVS?

A
Most vascuar beds are in parallel.
Therefore
- All tissues get oxygenated blood
- Allows regional redirection of blood
- Exceptions prove the rule
4
Q

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

A

Cardiac output = 4%

Oxygen consumption = 10%

5
Q

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

A

215 ml/min

6
Q

What is the overall resting cardiac output?

A

5000 ml/min

7
Q

What is the pressure difference equal to?

A

Pressure difference = mean arterial pressure - central venous pressure

-Affects all tissues

8
Q

How is flow calculated (equation)?

A

Change in pressure/Resistance

  • Controlled by radius^4
  • Selectively redirects flow
9
Q

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

A

Arterioles

10
Q

Features of the Aorta

A

Elastic arteries = aorta

  • wide lumen, elastic wall
  • damp pressure variations
11
Q

Features of arteries

A

Muscular arteries = other arteries

  • wide lumen, strong non-elastic wall
  • low resistance conduit
12
Q

Features of arterioles

A

Resistance vessels = arterioles

  • narrow lumen, thick contractile wall
  • control resistance & therefore flow
  • allow regional redirection of blood
13
Q

Features of capillaries

A

Exchange vessels = capillaries

- narrow lumen, thin wall

14
Q

Features of venules and veins

A

Capacitance vessels = venules & veins

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