Functioning Organisms - 04 The Respiratory System


Published on

A look at the human respiratory system for Year 8 Science students from Saint Ignatius College Geelong

  • Be the first to comment

No Downloads
Total views
On SlideShare
From Embeds
Number of Embeds
Embeds 0
No embeds

No notes for slide

Functioning Organisms - 04 The Respiratory System

  1. 1. FUNCTIONING ORGANISMS. 04. Respiratory system. Ian Anderson Saint Ignatius College Geelong
  2. 2. RESPIRATORY SYSTEM.  Responsible for  Moving air into & out of our body.  Gas exchange.  Absorbs oxygen from the air into the bloodstream.  Releases carbon dioxide into the air from the bloodstream. Source:
  3. 3. RESPIRATORY SYSTEM. Respiratory surface. The site of gas exchange must be:  Moist.  So that O2 and CO2 can dissolve before moving across the respiratory surfaces.  Have a large surface area.  So that large volumes of gases can move into and out of our bodies quick enough.  Must be thin & porous.  So that the gases can move across it.
  4. 4. RESPIRATORY SYSTEM. In aquatic organisms such as fish, crustaceans & molluscs, etc. gas exchange usually occurs across gills.  External respiratory surface.  In direct contact with water & dissolved gases.  Always moist.  No danger of drying out. Source: 53figs/GenBiopics.html Source:
  5. 5. RESPIRATORY SYSTEM. In land animals the respiratory surfaces run the risk of drying out.  Answer is to make the respiratory surface internal.  e.g. lungs in vertebrates, tracheal system in insects, visceral cavity (primitive lung) of land snails. Source: Mason et al. (2011)
  6. 6. HUMAN RESPIRATORY SYSTEM. Includes:  Lungs.  Pathways connecting lungs to external environment.  Diaphragm. Source:
  7. 7. HUMAN RESPIRATORY SYSTEM.  We have two lungs in our chest.  Air pathways are a series of tubes that get narrower and narrower.  Trachea  bronchi  bronchioles  alveoli. Source:
  8. 8. HUMAN RESPIRATORY SYSTEM. Alveoli.  Tiny air sacs at the end bronchioles.  Site of gas exchange.  Surrounded by a rich supply of blood capillaries. Source: Enger et al. (2011)
  9. 9. HUMAN RESPIRATORY SYSTEM. Alveoli.  Moist, thin & porous and have a large surface area.  Allows diffusion to occur between the air in the alveoli and gases in the blood.  CO2 from bloodstream into alveoli.  O2 from alveoli into bloodstream. Source:
  10. 10. HUMAN RESPIRATORY SYSTEM. How we breathe.  The lungs are not muscles! We rely in our diaphragm & intercostal muscles to breath. Source: Sharwood (2005)
  11. 11. HUMAN RESPIRATORY SYSTEM. How we breathe.  Inhalation (breathing in).  Diaphragm contracts.  Increasing volume of our thoracic cavity.  Forcing air in through our air pathways and into our lungs. Source:
  12. 12. HUMAN RESPIRATORY SYSTEM. How we breathe.  Exhalation (breathing out).  Diaphragm relaxes.  Decreases volume of our thoracic cavity.  Forcing air out via our air pathways into the external environment. Source:
  13. 13. WHEN THINGS GO WRONG. The health of our respiratory system is critical to our survival.  If our respiratory system does not function optimally then we are unable to deliver oxygen to and remove carbon dioxide from our blood.  Our cells may also be unable to exchange carbon dioxide for oxygen, and are therefore unable to undergo all essential metabolic activities.  Often respiratory illnesses are can lead to other illnesses, in particular cardiac disease.
  14. 14. WHEN THINGS GO WRONG. Bronchitis.  Swelling of the bronchi and/or production of excess mucous, resulting in constriction the airways.  Main symptom is coughing.  May be caused by colds & flu, smoking, etc. Source:
  15. 15. WHEN THINGS GO WRONG. Asthma.  Swelling of the bronchi and production of excess mucous, resulting in constriction of airways.  Symptoms include difficulty breathing, wheezing, etc.  May be caused by an overactive immune system (e.g. allergies), stress, etc. Source:
  16. 16. WHEN THINGS GO WRONG. Emphysema.  Caused by loss of elasticity to bronchi and alveoli reducing exchange of gases.  Symptoms include shortness of breath, etc.  May be caused by smoking, long-term exposure to pollutants or dust. Source:
  17. 17. BIBLIOGRAPHY. Enger, E.D., Ross, F.C., & Bailey, D.B. (2011). Concepts in Biology. New York: McGraw-Hill. Raven, P.H., Johnson, G.B., Mason, K.H., Losos, J.B., & Singer, S.R. (2011). Biology. New York: McGraw-Hill. Russell, P.J., Hertz, P.E., & McMillan, B. (2011). Biology: The Dynamic Science. Canada: Thomson Brooks/Cole. Sharwood, J. (Ed.). (2005). Science Edge 2. Melbourne: Thomson Learning.
  18. 18.