6.3.3

Nusaiba M. and Sabrina J.

6.3.3

Outline the role of skin and mucous membranes in defense against pathogens
A pathogen is any thing that can cause a disease. This includes viruses, protozoa, fungi, bacteria, etc. Pathogens can be living or non-living.

The Skin

  • physical barrier
  • sebaceous glands- create lactic acids and fatty acids which creates an acidic environment in which pathogens cannot grow.
  • two layers: the lower layer contains glands, sensory receptors, and dermal cells. It is what makes the skin strong and structured.
  • The top layer is constantly replaced by dead dermal cells. Ideal to fight pathogens because they are not really alive.

The Mucous Membrane

  • Protect internal structures
  • a thin region containing fluids to wash away pathogens
  • contain biochemical defense agents
  • mucous membranes may also aid in the removal of pathogens
  • ideal for defense against pathogens who enter via nasal passages or mouth (both the trachea and nasal passages are lined with mucus membranes)

Bibliography

Damon, Alan, McGonegal, Randy, Tosto, Patricia, and William Ward. Higher Level Biology. Upper Saddle River: Pearson Education, Inc., 2007. Print. 163-164.

"Protection Against Infectious Disease." IB Guides. n.p., n.d. Web. 25 September 2014. <http://ibguides.com/biology/notes/defence-against-infectious-disease>.