7.06 immune system.rtf - Biology Notebook 07.06 Immune...

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Biology Notebook: 07.06 Immune System Objectives: ·0 Identify the body systems that protect from pathogens ·1 Summarize how the cells of the immune system respond to pathogens ·2 Identify specific and nonspecific immune responses and the body systems that produce them ·3 Identify methods used to control pathogens ·4 Explain how vaccines artificially produce acquired immunity Key Questions and Terms Notes Nonspecific Defenses Define pathogen. A virus of microorganism that causes disease in its plant or animal host. What are the four most common types of pathogens? 1. Viruses 2. Bacteria 3. Fungi 4. Protozoa Give an example of a virus and how it spreads. Viruses are nonliving infectious particles made up of viral genes enclosed in a protein capsule. They can only replicate within a host cell, which they identify with a lock and key fit between the proteins on the outside of their capsules and specific molecules on the surface of the cell. Cold, flu, measles, smallpox, genital herpes, and HIV. Give an example of a bacteria and how it spreads. Bacteria are single-celled organisms that are shaped like rods, spheres, or spirals. Not all bacteria are harmful; less than 1 percent of the bacteria on Earth cause disease. Bacteria cause diseases like tuberculosis, strep throat, and urinary tract infections. Give an example of fungi and how it spreads. Fungi include a large range of eukaryotic organisms such as yeast, mold, and mushrooms. Some fungi do cause illness. Candida is a type of yeast that can cause infections of the mouth and throat in infants and people taking antibiotics. Other fungi can cause skin problems such as ringworm and athlete’s foot. Give an example of a protozoa and how it spreads. Protozoa are single-celled organisms that hunt and gather other microbes for food. Protozoa
often spend at least part of their life cycle outside of human or animal hosts. They can invade people’s bodies through contaminated food or water to cause diseases such as toxoplasmosis and giardia, while malaria is transmitted by mosquitoes. Describe nonspecific defenses. a combination of physical and chemical barriers What are examples of external defenses? How do they protect the body? Skin covers the body’s surface and forms a physical barrier that protects the systems inside the body. Very few pathogens can penetrate the layer of dead cells on the skin’s surface. The external defense system also uses chemical defenses to deter pathogens from infecting the skin or entering the body. For example, secretions from the skin’s oil and sweat glands are acidic, which is an unwelcoming environment for many bacteria and microorganisms. Saliva, mucus, and tears help prevent pathogens from entering the body through the mouth, nose, and eyes. These secretions contain enzymes that break down bacterial cell walls, another example of a chemical defense.

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