The external barriers that a pathogen would have to overcome to break inside the human body are the skin, mucus membranes, and areolar tissue. These barriers act as physical and chemical defenses against pathogens.
The external barriers that a pathogen would have to overcome to break inside the human body are part of the body's first line of defense. These barriers include the skin, mucus membranes, and areolar tissue. The skin acts as a physical barrier, preventing pathogens from entering the body. It is covered with a layer of dead keratinized epithelium that is dry and inhospitable for pathogens. Mucus membranes, such as those lining the respiratory and digestive tracts, produce mucus that traps and removes pathogens. Areolar tissue contains immune cells that can detect and destroy pathogens.