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Explore the basics of infectious diseases, pathogens, STDs, antibiotics, and immune responses. Learn how the body fights against bacteria and viruses through nonspecific and specific defenses.
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40-1 Infectious Disease • What is a disease? • Any change, other tan an injury, which disrupts the normal functions of the body. • What three things cause diseases? • 1. Inherited • 2. Environment • 3. Bacteria, viruses and fungi
40-1 Infectious Disease • What are pathogens? • Disease-causing agent, such as a bacterium or fugus. • A. How Diseases Are Spread • 1. What is the best method for fighting any disease? • Avoid it • 2. What are the three ways that diseases are spread? • i. One person to another • ii. Contaminated water or food • Iii. Infected animals
40-1 Infectious Disease 3. Sexually Transmitted Diseases a. How are some of the most dangerous pathogens spread? Sexual contact b. What are two examples of STD’s caused by bacteria? i. Syphilis ii. gonorrhea c. What are four examples of STD’s caused by viruses? i. Hepatitis B ii. Hepatitis C • Genital herpes • AIDS
40-1 Infectious Disease B. Fighting Infectious Diseases 1. What are antibiotics? • Compounds that kill bacteria without harming the cells of humans or animals 2. How do antibiotics work? • By interfering with the cellular processes of microorganisms 3. What are the two ways antibiotics are produced? a. Naturally living organisms b. Produced synthetically • How does Penicillin interfere with bacteria growth? • Interferes with the synthesis of cell walls by bacteria, crippling fast-growing, walled bacteria
40-2 The Immune System A. Nonspecific Defenses • What system is the body’s primary defense against pathogens? • The immune system
40-2 The Immune System 2. First Line of Defense a. What is the job of the body’s first line of defense? • Keep out pathogens b. What is the body’s most important nonspecific defense? • Skin c. What is the purpose of dead cells at the skin’s surface? • Very few pathogens can penetrate the layers of dead cells d. How does the skin defend against or kill bacteria? • Oil and sweat glands in the skin produce an acidic environment • What can happen when your skin is broken? • Pathogens can enter your body and multiply
40-2 The Immune System 3. Second Line of Defense a. When pathogens enter your body, where are the toxins released? • Tissue b. What is the body’s second line of defense? • Inflammatory response c. What is the inflammatory response? • Reaction to tissue damage caused by injury or infection d. How do white blood cells fight infection? • Engulf and destroy bacteria • What is another name for the white blood cells that engulf and destroy bacteria? • phagocytes
40-2 The Immune System What are the body’s 2 major nonspecific defenses against invading pathogens (hint: first line of defense and second line of defense)? o Skin o Inflammatory response
40-2 The Immune System (part II) A. Specific Defenses 1. What is the substance that triggers immune response? • antigen
40-2 The Immune System (part II) 1. Humoral Immunity a. What is an antibody? • A protein that helps destroy pathogens b. What is the function of the two antigen-binding sites? • So, tow antibodies can bind to each c. Why do antibodies want to link viruses into a large mass? • So, they can engulf and destroy the whole mass d. What happens if the immune system can produce enough antibodies for a particular virus? • Prevent the virus from infecting cells e. Why do antibodies bind to the surfaces of bacteria? • They mark the cells for destruction by phagocytes
40-2 The Immune System (part II) 2. Permanent Immunity a. Once the body has been exposed to a pathogen, memory cells remain capable of producing what? • B and T cells remain capable of producing specific antibodies to that pathogen. • What do these memory cells ensure? • The disease never gets a chance to develop a second time
