QUIZ 1. What protein toughens the outer layer of the skin so it can be a barrier against infection? a. Elastin b. Keratin c. Collagen d. Actin Answer: b. Keratin is part of the epidermis. It leads to toughening of the skin so that it can better resist the passage of pathogens through the tissues. It helps provide a mechanical barrier for the skin. 2. What component of mucous membranes least likely prevents disease? a. Movement of cilia b. Antibacterial proteins c. Mucus d. Phagocytosis Answer: d. Each of these is important in helping mucous membranes fight disease except for phagocytosis, which is not a function of the mucous membranes. 3. What part of the GI tract contains hydrochloric acid to protect the system against pathogens? a. Esophagus b. Mouth c. Stomach d. Small intestine Answer: c. There are specialized cells in the stomach that make hydrochloric acid that is protective against pathogenic bacteria.
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