VIEWS: 6 PAGES: 40 POSTED ON: 8/12/2011
Diseases Lack of Homeostasis 1. What is disease? A disease is any change, other than an injury, that disrupts the normal functions of the body. The opposite of homeostasis. 2. Give 5 causes of disease. 1. Genetics –you are born with a the disease, it is in your DNA 2. Infection – you catch the disease from another organism. 3. Environment – you can get diseases from pollutants and poisons where you live. 4. Organ Malfunction – you can get a disease when one or more of your organs is not functioning properly. 5. Lifestyle Choices - like… 3. What is a pathogen? Disease-causing agents such as bacteria, viruses and fungi are called pathogens. Pathogen means “sickness maker.” Diseases caused by pathogens are generally called infectious diseases because the agents that cause them usually enter, or infect, the body of the person who gets sick. 4. What are 5 ways diseases are spread? 1. Coughing 2. Sneezing 3. Physical contact (STDs) 4. Contaminated water or food 5. Infected animals (vectors) The Immune System The body’s protection 1. What is the immune system? The immune system is the body’s primary defense against pathogens. It consists of nonspecific and specific defenses against infection. It includes the skin, blood, lymph nodes, lymph vessels and spleen. 2. Define Immunity. Immunity is the resistance of an organism to disease. If you are immune to a disease you will not get it. Example: Will Smith was immune to the disease in the movie I Am Legend. He will never get the disease. 3. Define Susceptibility. Susceptibility is the organism’s lack of immunity. If you are susceptible to a disease you may get sick when exposed to it. Example: People who do not get a flu vaccine shot are susceptible to the flu and will get sick if they are exposed to the virus. 4. What is the Human body’s 1st line of defense? It is the intact skin and mucous membranes, which release antibacterial fluids such as mucus, saliva and tears. The body’s first line of defense against disease is designed to keep invaders out! Nonspecific meaning it blocks everything! 5. What is the Human body’s 2nd line of defense? The body’s second line of defense is the inflammatory response. It involves sending white blood cells (phagocytes) to the site of the invasion. They use phagocytosis to engulf invading pathogens that have made it past the skin into the body. This is what is happening when you get inflammation! Nonspecific because they will engulf all invaders! Draw it… 6. What is the Human body’s 3rd line of defense? The immune response is the body’s third line of defense. It is specific, meaning the response is different depending on the invader. a. How does a fever help fight infection? An elevated temperature slows down or stops the growth pathogens. The higher temperature speeds up the heart beat to get white bloods cells (phagocytes to the site of infection faster.) An increased temperature speeds up the activities of the white bloods cells and the rate of the chemical reactions that help repair damaged tissue. Viruses Viruses living or non living? Viruses cannot reproduce by themselves. They infect your body cells and use their machinery to make more viruses. They destroy your cells as they do this, making you feel sick and doing damage. b. What are interferons and how do they fight infection? A group of proteins produced by virus infected cells that help other cells resist the virus. They are called interferons because they interfere with the virus. They slow down the reproduction of the virus and give the immune system time to respond. The Immune Response The body’s reaction 1. Define Antigens and give 6 examples. An antigen is a protein found in the cell membrane. Your body recognizes it’s own antigens as “self” and antigens on pathogens as “invaders.” The following have antigens that can trigger an immune response. Pathogens Allergens 1. Bacteria 4. Pollen/Dust 2. Virus 5. Foods 3. Fungus 6. Pet Hair Antigens Body Cell Pathogen Antigens Because antigens are made of protein, what is going to be very important? 2. Define Antibodies. An antibody is a protein produced by the body that combines with an antigens in the membrane of the pathogen and this neutralizes it (so it can’t make you sick). Masses of pathogens and antibodies are then engulfed and destroyed by white blood cells. 3. Describe how ANTIGENS and ANTIBODIES fit together. Antibody and antigen fit together like a lock and key. They are made of protein so SHAPE is important. Each antibody is specific for a single kind of antigen. 4. This antibody is specific for one of the antigens shown. Circle the correct antigen. (Hint shape is important here!) 5. What three areas of the body make antibodies? Lymphocytes (white blood cells that make antibodies are found in the) 1. lymph nodes 2. bone marrow 3. spleen 6. How do antibodies and phagocytes work together to fight pathogens? Antibodies bind to antigens on pathogens (invaders like viruses and bacteria) and clump them together in large masses. These large masses are engulfed and destroyed by special white blood cells called phagocytes. 7. Draw a phagocyte engulfing the antigen-antibody complex below: 8. Explain the functions of 3 types of Lymphocytes “White Blood Cells.” 1. Memory B Lymphocytes – white blood cells that respond to specific antigens by beginning to produce antibody proteins that will bind only with that antigen. As time goes on the body will have many different types of B cells, each producing antibodies for one specific antigen. 8. Explain the functions of 3 types of Lymphocytes “White Blood Cells” 2. Killer T Lymphocytes – white bloods cells that recognize cells in the body that have been infected with microorganisms. They punch holes into the infected cell sometimes injecting poison in to kill the microorganism and often the infected cell along with it. 8. Explain the functions of 3 types of Lymphocytes “White Blood Cells” 3. Helper T Lymphocytes – Help B cells and Killer T cells do their jobs. They are the cells that are destroyed by the human immunodeficiency virus (HIV), which results in the disease called AIDS. When these cells cannot do their job the immune system is weakened significantly. 1. Passive Immunity: a. Definition: Antibodies produced by another organism are given to an individual. The antibodies produce a passive immunity against a specific pathogen. You do NOT get a memory B cell! b. How long does it last? As long as they remain in the blood stream, usually for several weeks until the body destroys the antibodies. Example Explain Maternal Immunity: The mother passes antibodies to the fetus through the placenta and to a newborn through breast milk. This protects the baby from infections during the first few months of its life. 2. Active Immunity a. Definition: The individual builds its own antibodies by being exposed to the disease in a strong or mild form. b. How long does it last? For a lifetime because you have your own Memory B Lymphocytes for that produce antibodies against that disease. Examples 1. Vaccination: You are injected with a weakened form of a disease. It doesn’t make you sick it just gives you the memory B cells to make antibodies against the disease. Polio vaccine 2. Exposure to the pathogen: Your body will naturally build up antibodies that last forever. Have you ever had chicken pox? If so, when? Did you get it a second time? IMMUNE SYSTEM DISORDERS Problems with the system Autoimmune Diseases 1. Explain what happens to the body. Autoimmune diseases occur when the immune system makes a mistake and attacks the body’s own cells doing damage. Example Diabetes (Juvenile-Onset): Explain An autoimmune reaction that attacks the insulin producing cells in the pancreas. The person does not produce insulin and must have injections of insulin to regulate blood sugar. (Can’t maintain homeostasis!) Immune Deficiency Diseases 1. Explain what happens to the body. The bodies immune system is under- active because it has been weakened. Examples What is AIDS? It is an acquired disease, not inherited, that weakens the immune system and causes certain symptoms. They have a lowered number of helper T lymphocytes. What is HIV? Human Immunodeficiency Virus is the virus that causes the symptoms that we call AIDS. It kills off helper T Cells gradually causing AIDS. This can take a while to make someone sick. Allergies a. Explain what happens to the body. Antigens from allergens bind to mast cells, immune cells, and causes them to release histamines. b. What are histamines? Released by mast cells they cause runny nose, itchy eyes and skin and watery eyes. Example Explain Peanut Allergies When people eat peanuts they have an allergic reaction because their body recognizes the antigens on peanut cells as an invader and attack. This can cause inflammation that causes trouble breathing. Do you have an allergy? Transplants When someone gets a transplant. The antigens on the organ must match or be very similar to the antigens in the sick person’s body. Then their immune system will not attack it. Antibiotics Do not give you immunity. They only work with bacterial infections NOT viruses. They kill bacteria in your body.
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