IMMUNOLOGY

Detailed explanation-1: -Mechanical barriers-which include the skin, mucous membranes, and fluids such as tears and urine-physically block pathogens from entering the body.

Detailed explanation-2: -Natural barriers include the skin, mucous membranes, tears, earwax, mucus, and stomach acid. Also, the normal flow of urine washes out microorganisms that enter the urinary tract.

Detailed explanation-3: -We have already discussed several examples of mechanical defenses, including the shedding of skin cells, the expulsion of mucus via the mucociliary escalator, and the excretion of feces through intestinal peristalsis.

Detailed explanation-4: -Mechanical Defenses For example, the flushing action of urine and tears serves to carry microbes away from the body. The flushing action of urine is responsible for the normally sterile environment of the urinary tract. The eyes have additional physical barriers and mechanical mechanisms for preventing infections.

Detailed explanation-5: -Antibodies can bind to foreign antigens and activate complement through the classical pathway and foreign substances can bind to spontaneously activated C3 and stabilize it. Which of the following is NOT a mechanism of complement action? sebum.

Detailed explanation-6: -Physical barrier The skin is the impermeable physical/mechanical barrier that protects many pathogens from entering the body. Similarly, mucosa or mucous membranes that line the immediate internal systems help trap pathogens by producing mucous.