This video gives a detailed account of the Immune System's first line of defense.
WATCH IT AND TAKE NOTES
(Don't use the cc... They are terribly inaccurate. Use headphones)
An overview of the First Line of defense.
first line immunology.pptx
The Body's 3 Lines of Defense:
Check it out...
Look at the differences between the structures in the skin vs the internal epithelium. They all protect the body from the external environment in different ways.