HOMEWORK Monday NIGHT Nervous system questions in short answer booklet 14-26 Answers should be a few words Will review in class tomorrow HOMEWORK Tuesday night Immune system questions in short answer booklet 36-52, 101, 105 Answers should be a few words Will review in class tomorrow HOMEWORK Wednesday night Skeletal and muscle questions in short answer booklet 92-103 Bring in red and blue pencils tomorrow Lesson 4-Unit 4 AIM: How does the immune system help maintain homeostasis in the human body? What is Immunity? • Immunity – the ability of the body to fight infection through the production of cells that kill/stop foreign substances or cells. What is disease? • Disease is defined as “an illness or condition that prevents the body from functioning normally.” Communicable Diseases Certain germs cause communicable diseases. These are contagious diseases. A widespread outbreak of a disease is called an epidemic. A non-communicable disease is a disease that cannot be passed from one person to another like heart disease, diabetes and cancer. PATHOGENS • Pathogens are germs. There are three different kinds of pathogens. They are bacteria, viruses, and fungi. HOMEWORK Tuesday night Immune system questions in short answer booklet 36-52, 101, 105 Answers should be a few words Will review in class tomorrow What is a bacteria? • Bacteria are single celled prokaryotic cells. There is no nucleus or organelles. There is a single loop of DNA. • They are alive. They can be killed with antibiotics. How do bacteria reproduce? • Bacteria reproduce by making exact copies of themselves. They grow rapidly. • Because they are alive, they can be killed. That is where antibiotics come in. How do antibiotics work? An antibiotic is a selective poison. Each different type of antibiotic affects different bacteria in different ways. Some affect the cell membrane of the bacteria. Some antibiotics work on killing the organelles in the bacteria. • Antibiotic resistant bacteria Superbugs are bacteria that are resistant to several different antibiotics. Bacteria can become resistant to antibiotics by mutating (changing) their genes after being in contact with an antibiotic. These changes allow the bacteria to survive or ‘resist’ the antibiotic. Viruses • Viruses are not alive. They get into living cells and take over the DNA of the cell. • A virus particle is made of the following: • 1. Nucleic acid - set of genetic instructions • 2. Coat of protein that protects the genetic instructions How viruses reproduce 1.A virus particle attaches to a host cell. 2. It releases its genetic instructions into the host cell. 3.The injected genetic material recruits the host cell's enzymes. 4.The enzymes make parts for more new virus particles. 5.The new particles assemble the parts into new viruses. 6.The new particles break free from the host cell and go into other cells. “How Are Diseases Transmitted Many ways... they can travel through the air, in contaminated food or water, or infected body fluids like blood. First line of defense-your skin-9 The epidermis is a block for a lot of germs. The skin has chemicals that kill some bacteria, but if there is an open wound or cut, the germs can still get in. 2nd line of defense Tears and saliva have chemicals in them that break down cell walls of some bacteria and viruses. Acid in your stomach also breaks down germs. First and second lines of defense-11 saliva antibacterial enzymes skin prevents entry stomach acid low pH kills harmful microbes tears antibacterial enzymes mucus linings traps dirt and microbes The Immune System-12 If a bacteria or virus gets pasts these defenses, our body has a built in system called the immune system- to find and kill microbes. The soldiers of the immune system are different kinds of white blood cells. Where are white blood cells found? • White blood cells travel around in the blood vessels all over the body. • White and red blood cells are in blood. Blood has plasma, white blood cells and red blood cells Blood is actually made up of several different kinds of cells. To separate the different parts in the blood, it is placed in a special spinner called a centrifuge. When the blood is spun around, the red blood cells - the heaviest part of the blood go to the bottom of the tube. After it is separated, the white blood cells are in the middle. The red blood cells are on the bottom. The plasma, which contains digested food and vitamins, is on the top. Lymphatic system WBCs travel in the blood vessels. Other WBCs are in the lymphatic system. This system is made up of thin tubes, called lymph vessels that branch throughout all parts of the body. Along this network of vessels are groups of small, beanshaped organs called lymph nodes. Lymph nodes-17 There are more than 100 tiny, oval structures called lymph nodes. The lymph nodes MAKE, STORE AND SEND OUT the white blood cells to destroy germs. There are different types of white blood cells that have different jobs. What triggers the Immune Response? There are special markers on the outside of the bacteria or virus that identify it. The markers also tell your body if it doesn’t belong and triggers an immune response. These markers are called antigens. Antigens and Antibodies Antigens are specific proteins that are found on the surface of a pathogen. The surface of every germ has a unique design. This is their identity card to the body. When an antigen enters the body, the immune system produces antibodies against it. It is like a battle with the army (antibody) fighting off the invader (antigen). B-Lymphocytes The invader is the antigen. The army is the white blood cells. B Lymphocytes are one kind of white blood cell. They look like this at first. They have no specific shape. B-Lymphocytes are one kind of white blood cell. • B-Lymphocytes change form so they can make antibodies that attach themselves to the antigen and fit exactly like a puzzle. Measles antigen Measles antibody • The antibodies are always Y shaped. 23 VICTORY!! the antibody attaches to the antigen. It can’t go anywhere and it can’t reproduce anymore. antibody Once antigen Another kind of white blood cell is a macrophage • Macrophages are the biggest blood cells. They destroy foreign substances (antigens) and gobble them up. HOORAH!! • When the antibody binds to the antigen, it stops its movement. Then, macrophages can come to gobble it up. Extra antibodies remain in the body as memory cells. A Pathogen Gets into Your Body (Memory antibodies) stay in body that are already made and can quickly go to attach to THAT PATHOGEN the next time it gets in your body!!! Why do you think this baby is getting a shot in his arm? He is getting a Vaccination A vaccination is an injection of a weakened form of the actual antigen that causes the disease. The injection is too weak to make you sick, but your lymphocytes will make antibodies for it. Active or Passive Immunity •If you actually get an infectious disease (like Chicken Pox), antibodies are automatically produced. Another name for these antibodies is MEMORY cells. They stay in the body and will remember if another chicken pox germ enters your body. That is active immunity. •Passive Immunity- getting the immunity by means of a vaccination or through the mother during pregnancy. Immune System Disorders Allergy – the body does not recognize ordinary things like pollen, shrimp, or peanuts and the immune system reacts. Transplants Transplant rejection occurs when the body recognizes the organ as foreign and mounts an immune response against it. This is more likely to happen if the organ comes from a different person or not a relative. Immunosuppressant drugs – suppress the immune system so it does not attack the transplanted organ. Autoimmune Disease The immune system can make a mistake and attack its own body cells Examples of autoimmune diseases are Crohns’s disease and ulcerative colitis. AIDS AIDS is a virus that attacks the immune system of the person who has the disease. If a person becomes infected with AIDS, they will find it harder to fight off infections and diseases. The virus takes T lymphocyte cells and turns them into AIDs viruses. Those T lymphocyte cells used to be fighter immune cells. Over time, most helper T-Cells are killed. The body can’t fight infections. It is spread by contact with infected blood and other body fluids. CANCER A problem with the controls that regulate cell growth and division. Cells grow and divide uncontrollably, forming a tumor. It can be caused by genes, certain chemicals, or random mutations. 3 Types: A, B, O If a person is given the wrong blood type the body recognizes it as foreign and will produce antibodies to fight it. This results in the clumping of blood which will clog capillaries and result in death.