9.3 Natural Fluid Systems

1
9.3 Natural Fluid Systems

• Many natural systems are based on fluids and
  pressures
• Weather systems are created and influenced by
  barometric pressure, measure with a barometer.
• Air pressure is measured in kilopascals (kPa)
• or atmospheres (atm)
• Humans are affected by air pressures (breathing)
• and fluid pressures (the circulatory and
• respiratory systems)
• Water, and water balance, is vital for life
• The human body is 66 water, and
• loses 2.1 L of water daily

See pages 334 - 335
2
The Circulatory System

• The circulatory system is one of the most complex
  hydraulic systems we know
• The heart is the pump, and blood vessels are
  specialized pipes
• Blood pressure refers to how hard blood pushes
  against the walls of your bodys blood vessels
• Nerve cells in the arteries monitor blood
  pressure
• Your pulse is these waves of pressure
• Normal resting heart rate is 60 - 100 beats per
  minute
• Blood pressure is measured with a
  sphygmomanometer
• which measures two different pressures
• Eg. Blood pressure 120/75 mm Hg two pressures
• 120 heart pumping, and
• 75 heart relaxing and filling with blood

See page 336
3
Disorders of Blood Circulation

• Blood pressure is a part of normal check-ups, as
  it is an indicator of overall health
• Like in all hydraulic systems, roughness inside
  of pipes decreases the hydraulic systems
  effectiveness
• Fatty deposits build up in arteries to slow blood
  flow
• Smoking and obesity also increase blood pressure

See page 337
www.nhlbi.nih.gov
4
The Respiratory System

• Breathing is partly based on air pressure changes
• Air (and all fluids) normally move from high to
  low pressure
• Inhaling expands the rib cage, increasing volume
  and decreasing pressure
• The diaphragm and rib muscles expand your lungs
• Air from outside, which has oxygen in it, enters
  the low pressure in the lungs
• Exhaling is the diaphragm and rib
• muscles pushing inwards, increasing
• pressure in the lungs so air leaves
• As the air leaves, it takes
• unwanted carbon dioxide

See page 338
5
Disorders of Breathing

• Breathing is affected by narrowed passageways,
  especially swelling from infections and allergies
• Smoke, polluted air, coal dust and asbestos are
  also harmful
• Asthma is a respiratory disease that narrows the
  passageways for air entering and leaving the
  lungs
• Asthma can be triggered by smoke and pollutants,
  exercise, stress and dust
• An inhaler is used to deliver tiny droplets of
  medicine to the lungs to help passageways open

Take the Section 9.3 Quiz
See page 339