Blood

• Blood pressure


  The reason why blood circulates
• Blood will always flow from an area of high pressure to one of low pressure
• Functions of the respiratory system


  • Breathe in air from the environment
  • Transfer oxygen into the blood
  • Remove carbon dioxide from the blood
  • Return air back to the environment
  • Create speech as air is moved out over the larynx
• Systolic blood pressure


  The highest pressure and is the pressure on the arteries as the left ventricle contracts (120 mmHg)
• Diastolic blood pressure


  The lowest pressure and is the pressure on the arteries as the left ventricle relaxes (80 mmHg at rest)
• Hypertension


  Having a blood pressure higher than 140 mmHg over 90 mmHg
• Uncontrolled high blood pressure

  Can lead to: artery damage and narrowing, coronary artery disease, enlarged left heart, heart failure, stroke, kidney failure
• Maximum heart rate


  220 - your age
• As your age increases


  Your maximum heart rate will decrease
• Stroke volume (SV)


  The amount of blood ejected by the left ventricle in one contraction
• Inspiration (breathing in)


  1. Diaphragm muscle contracts and flattens

  2. Intercostal muscles raise the thorax and sternum out

  3. Chest cavity is now bigger which lowers the pressure in the lungs to less than that of the environment

  4. Air is drawn into the lungs
• Expiration (breathing out)


  1. Diaphragm muscle relaxes and forms a dome shape

  2. Intercostal muscles relax to lower thorax and sternum

  3. Chest cavity is now smaller which raises the pressure in the lungs to more than that of the environment

  4. Air is drawn out of the lungs