Here's why:
* Physical Barrier: The skin acts as a physical barrier, preventing microorganisms from entering the body.
* Secretions: The skin produces sweat and sebum (oil), which have antimicrobial properties.
* Normal Flora: The skin also harbors a diverse community of beneficial bacteria (normal flora) that compete with harmful microorganisms for space and resources.
While the skin is the primary first line of defense, other organs and structures also play a role:
* Mucous membranes: Line the respiratory, digestive, and urinary tracts, trapping and expelling pathogens.
* Tears: Contain lysozyme, an enzyme that breaks down bacterial cell walls.
* Saliva: Washes away microorganisms and contains antibacterial enzymes.
* Stomach acid: Destroys most ingested pathogens.
Let me know if you'd like to know more about any of these!
