Anatomy and Physiology Answer Key

Eosinophils also show some phagocytic properties

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Unformatted text preview: unfavorable to microbial growth. The pH of gastric juice is low enough to kill microbes directly. Other secretions (tears, saliva) wash microbes away, preventing them settling on surfaces, sweat contains an enzyme that destroys some types of bacterial cell walls, urine flushes potential pathogens from the urinary tract. (e) Antimicrobial properties prevent multiplication of microbes (especially viruses). (f) Produced against specific pathogens, antibodies bind and destroy pathogens or their toxins. (g) Fever raises general body temperature and metabolic rate which speeds up the blood flow and the rate of delivery of white blood cells to the site of infection. Fever also intensifies the effect of interferon. (h) T cells recognize and destroy specific target pathogens directly on contact. Other T cells assist in the process, for example, by regulating the activity of other lymphocytes. (i) Heat inhibits the activity of the pathogens at the site of infection. Swelling and pain help to confine the infection to a limited area by limiting movement, increased blood flow speeds up the delivery of white blood cells and speeds healing. 4. The Action of Phagocytes (page 134) 1. Neutrophils, eosinophils, macrophages. 2. By looking at the ratio of white blood cells to red blood cells (not involved in the immune response). An elevated white blood cell count (specifically a high neutrophil count) indicates microbial infection. 3. Microbes may be able to produce toxins that kill phagocytes directly. Others can enter the phagocytes, completely filling them and preventing them functioning or remaining dormant and resuming activity later. Inflammation (page 135) 1. (a) Increased diameter and permeability of blood vessels. Role: Increases blood flow and delivery of leukocytes to the area. Aids removal of destroyed microbes or their toxins. Allows defensive substances to leak into the tissue spaces. (b) Phagocyte migration and phagocytosis. Role: To directly attack and destroy invading microbes and foreign substance...
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This document was uploaded on 01/28/2014.

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