9.3 Natural Fluid systems

(c) McGraw Hill Ryerson 2007 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 (c) McGraw Hill Ryerson 2007

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 body’s 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 (c) McGraw Hill Ryerson 2007

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 system’s 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 (c) McGraw Hill Ryerson 2007

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 (c) McGraw Hill Ryerson 2007

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 See page 339 (c) McGraw Hill Ryerson 2007 Take the Section 9.3 Quiz

Freeze! “High 5” Reading Checks How are blood vessels like pipelines? How is your circulatory system like a water balloon? What are two causes of high blood pressure?