Secondary "Muscle" Pump
  • can reduce heart's burden by 1/3 if muscles are used. 
  • Keep walking around to keep blood flowing and heart gets a break
Cardiovascular System
1. Blood
On average 5 liters of blood circulating
Plasma (55%)
  • Water - when you feel thirsty its too late
  • Nutrients
  • Salt - blood tastes salty
Blood Cells (45%)
  • White Blood Cells - fight infections, especially bacteria
  • Platelets - stop minor bleeding (clot)
  • Red Blood Cells - carry oxygen; one molecule of hemoglobin carries four oxygens (efficiency)
2. Heart
  • Roughly the size of a fist
  • Cardiac muscles
  • Has contractions by itself (involuntary)


  • Each part has atrium and ventricle, atrium on top, ventricle on bottom
  • one way valves - prevent  backwards blood flow between two halves
  • Systemic Circulation - our left ventricle, aorta artery (largest artery), arteries, arterioles, capillaries, venules, larger veins
  • Pulmonary/Lung Circulation - right atrium, right ventricle, arteries, arterioles, lungs
    - oxygenation - rocess of expelling CO2 and absorbing oxygen
3. Blood Flow
Blood pressure causes arteries to expand or contract; pressure in the large arteries
  • Systolic - maximum arterial pressure
  • Diastolic - minimum arterial pressure
  • Pulse Pressure - is equal to systolic-diastolic
Thoroughfare Channels
  • Small blood vessels that provide direct links between arterioles and venueles
One Way Valves
only in veins because:
  • In arteries you have a lot of pressure from the heart
  • In veins, blood is a lot less pressured (overcome gravity to get to the heart from foot)
  • Veins only allow blood to go to the heart
Cardiac Output

4. Cardiac Output
The amount of blood pumped out of the left ventricle per minute
Blood Flow Distribution
Factors that affect blood flow distribution include: 
Radii of Arteriols
adjusts depending on what part of body needs the blood
Resting Distribution
  • 20% of blood in muscles
  • 25% of blood in digestive system 
  • Skeletal < Digestive
  • Not supposed to have heavy meals after exercising
Cardiac Output equation
Cardiac Output (Liters per minute) Involves Factors:
  • Heart Rate (beats/minute)
  • Stroke Volume (L/beat)
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