Acts as a physical barrier that pathogens can't get through
Secretes oils and antimicrobial substances that can kill pathogens
Nose
Has hairs and mucus that trap pathogens and particles in the air
Trachea and esophagus
Only two tubes leaving the throat that pathogens have to go through
Trachea, bronchi, and bronchioles
1. Covered in mucus that traps particles
2. Lined with cilia that move mucus and trapped particles up to the throat to be swallowed
Stomach acid
Hydrochloric acid that kills most pathogens
Immune system
White blood cells that patrol the body
Phagocytosis - white blood cells engulf and destroy pathogens
Produce antitoxins to counteract toxins produced by pathogens
Produce antibodies specific to foreign antigens
Antigens
Substances detected as foreign by the immune system, such as bacteria or virus proteins
Antibodies
Small proteins made by white blood cells that can bind to specific antigens and signal for their destruction
The immune system remembers specific antibodies so it can quickly produce them again if the same pathogen is encountered in the future, making the person immune to that disease
