Final answer:
The body's nonspecific defenses include physical and chemical barriers like skin, mucus, and stomach acid, as well as nonspecific leukocytes that perform phagocytosis.
Step-by-step explanation:
The body's internal nonspecific defenses serve as the first line of defense against pathogens and foreign materials. The general properties of these defenses are not directed toward any specific pathogen but instead provide broad protection. The first line of defense includes a range of physical and chemical barriers such as the skin, tears, mucus, cilia, stomach acid, urine flow, and friendly bacteria. These barriers serve as a constant guard to prevent pathogens from entering the body, while mechanical actions like coughing and the flushing of bodily fluids work to remove any invaders that manage to breach these barriers.
In addition to physical barriers, the innate immune response involves nonspecific leukocytes that perform functions like phagocytosis, engulfing and breaking down pathogens that penetrate the initial defenses. The resident microbiota also competes with pathogens, further protecting the body from infections. If pathogens surpass these initial defenses, the body's second line of defense comes into play, which includes the inflammatory response and further actions by nonspecific leukocytes.