Chapter 6 Body Defenses and Disease

Section 1- Disease  Noninfectious disease: a disease that cannot spread from one individual to another.  These can be caused by a variety of factors including heredity and unhealthy life choices such as smoking, not exercising and eating unhealthy foods.  Avoiding these harmful habits may help you avoid noninfectious diseases.  Noninfectious disease: a disease that cannot spread from one individual to another.  These can be caused by a variety of factors including heredity and unhealthy life choices such as smoking, not exercising and eating unhealthy foods.  Avoiding these harmful habits may help you avoid noninfectious diseases.

Disease cont…  Infectious disease: a disease that is caused by a pathogen and that can be spread from one individual to another.  Pathogen: a microorganism, another organism, a virus, or a protein that causes disease.  Pathogens depend on living things to reproduce.  Infectious disease: a disease that is caused by a pathogen and that can be spread from one individual to another.  Pathogen: a microorganism, another organism, a virus, or a protein that causes disease.  Pathogens depend on living things to reproduce.

Pathway to Pathogens  There are many ways that pathogens can be passed from person to person.  1. Air: pathogens can travel through air and be ingested by someone while breathing. One sneeze has more than 100,000 tiny droplets on moisture that could contain pathogens.  2. Contaminated Objects: pathogens can live on objects for a given amount of time. If the healthy person touches the contaminated object, the pathogen is passed to them.  There are many ways that pathogens can be passed from person to person.  1. Air: pathogens can travel through air and be ingested by someone while breathing. One sneeze has more than 100,000 tiny droplets on moisture that could contain pathogens.  2. Contaminated Objects: pathogens can live on objects for a given amount of time. If the healthy person touches the contaminated object, the pathogen is passed to them.

 3. Person to Person: Pathogens can be spread from person-to-person through direct contact with the infected person through fluids. You can become infected through kissing, shaking hands, or touching sores of an infected person.  4. Animals: Pathogens can be carried by animals. The pathogens can reside in their fur, eyes, or mouth. After touching an unfamiliar dog or cat, you should wash your hands before touching yourself.  3. Person to Person: Pathogens can be spread from person-to-person through direct contact with the infected person through fluids. You can become infected through kissing, shaking hands, or touching sores of an infected person.  4. Animals: Pathogens can be carried by animals. The pathogens can reside in their fur, eyes, or mouth. After touching an unfamiliar dog or cat, you should wash your hands before touching yourself.

 5. Food and Water: The water supply in the USA is generally safe, but accidents do occur and pathogens can make it into the water supply and cause illnesses. Meat, fish and eggs that are not cooked enough can contain harmful bacteria or parasites. Refrigerate foods properly to decrease chance of bacteria forming. Washing all used cooking surfaces also helps to fight the spread of bacteria.

Dealing with Pathogens  Pasteurization: invented by Louis Pasteur. He discovered that by bring certain substances to a boil he was able to kill a large amount of bacteria. This method is still used today with things such as milk, cheese and wine.  Vaccines and Immunity: Immunity: the ability to resist or to recover from an infectious disease Vaccine: a substance that helps your body develop an immunity to a disease.  Pasteurization: invented by Louis Pasteur. He discovered that by bring certain substances to a boil he was able to kill a large amount of bacteria. This method is still used today with things such as milk, cheese and wine.  Vaccines and Immunity: Immunity: the ability to resist or to recover from an infectious disease Vaccine: a substance that helps your body develop an immunity to a disease.

Dealing with Pathogens cont…  Vaccines are used throughout the world to prevent many diseases that were deadly years ago.  Modern vaccines contain pathogens that are killed or specially treated and it allows your body to build up a defense against the disease.  Antibiotics: a substance that can kill bacteria or slow the growth of bacteria. They are also used for the treatment of fungi.  Vaccines are used throughout the world to prevent many diseases that were deadly years ago.  Modern vaccines contain pathogens that are killed or specially treated and it allows your body to build up a defense against the disease.  Antibiotics: a substance that can kill bacteria or slow the growth of bacteria. They are also used for the treatment of fungi.

Dealing with Pathogens cont…  Viruses, such as the common cold, are not affected by antibiotics. Antibiotics can only kill living things.  Viruses are not considered alive because they can not reproduce on their own.  To reproduce, viruses are dependent on organisms.  In the past, the only way to destroy viruses was to locate and kill the cells that the viruses had invaded.There have been many advances in medicine to allow for medications to kill viruses.  Viruses, such as the common cold, are not affected by antibiotics. Antibiotics can only kill living things.  Viruses are not considered alive because they can not reproduce on their own.  To reproduce, viruses are dependent on organisms.  In the past, the only way to destroy viruses was to locate and kill the cells that the viruses had invaded.There have been many advances in medicine to allow for medications to kill viruses.

Sect. 2-Your Body’s Defenses First Lines of Defense  Organisms that try to enter your eyes or mouth are usually destroyed by special enzymes.  Pathogens that enter through your nose are usually pulled down the throat by mucus to your stomach where they are quickly destroyed by the stomach’s environment.  Organisms that try to enter your eyes or mouth are usually destroyed by special enzymes.  Pathogens that enter through your nose are usually pulled down the throat by mucus to your stomach where they are quickly destroyed by the stomach’s environment.

 Your skin has many layers, the outermost is dead cells. As a result, many pathogens have a hard time finding a live cell to infect.  The dead skin calls are constantly dropping off your body and as they do pathogens fll off with them.  In addition, glands secrete oil onto your skins secrete oil onto your skin’s surface which kills many pathogens.  Your skin has many layers, the outermost is dead cells. As a result, many pathogens have a hard time finding a live cell to infect.  The dead skin calls are constantly dropping off your body and as they do pathogens fll off with them.  In addition, glands secrete oil onto your skins secrete oil onto your skin’s surface which kills many pathogens.

Failure of First Lines  When skin is cut or punctured pathogens can enter the body. The body acts quickly to keep out as many pathogens as possible.  Blood flow to the injured area increases.  Cell parts in the blood called platelets help to seal the wound so no more pathogens can get inside.  Immune system: the cells and tissue that recognize and attack foreign substances in the body.  When skin is cut or punctured pathogens can enter the body. The body acts quickly to keep out as many pathogens as possible.  Blood flow to the injured area increases.  Cell parts in the blood called platelets help to seal the wound so no more pathogens can get inside.  Immune system: the cells and tissue that recognize and attack foreign substances in the body.

 The immune system is not localized in any one place in your body.  The immune system is not controlled by any one organ such as the brain either.  The immune system is a team of individual cells, tissues, and organs that work together to keep you safe from invading pathogens.  The immune system is not localized in any one place in your body.  The immune system is not controlled by any one organ such as the brain either.  The immune system is a team of individual cells, tissues, and organs that work together to keep you safe from invading pathogens.

Cells of the Immune System  Macrophage: an immune system cell that engulfs pathogens and other materials.  T-Cells: an immune system cell that coordinates the immune system and attacks many infected cells  B Cell: a white blood cell that makes antibodies.  Antibodies: a protein made by B cells that bind to a specific antigen  Macrophage: an immune system cell that engulfs pathogens and other materials.  T-Cells: an immune system cell that coordinates the immune system and attacks many infected cells  B Cell: a white blood cell that makes antibodies.  Antibodies: a protein made by B cells that bind to a specific antigen

Fever  When macrophages activate the helper T- cells, they send a signal that tells your brain to turn up the thermostat in your body.  In a few minutes, the temperature in your body can rise several degrees.  A fever of one or two degrees actually helps you get well faster.  The increase in temperature slows the growth of some pathogens  Helps B cells and T cells multiply faster.  When macrophages activate the helper T- cells, they send a signal that tells your brain to turn up the thermostat in your body.  In a few minutes, the temperature in your body can rise several degrees.  A fever of one or two degrees actually helps you get well faster.  The increase in temperature slows the growth of some pathogens  Helps B cells and T cells multiply faster.

Memory Cells  Memory B Cell: a B cell that responds to an antigen more strongly when the body is reinfected with an antigen than it does during its first encounter with the antigen.  The first time you get infected with a virus the B cell does recognize it so you will get sick.  After the first time your body remembers what the virus looks like and has developed its antigen for the virus. It is likely you will not get sick from the same thing as severe the second time around.  Memory B Cell: a B cell that responds to an antigen more strongly when the body is reinfected with an antigen than it does during its first encounter with the antigen.  The first time you get infected with a virus the B cell does recognize it so you will get sick.  After the first time your body remembers what the virus looks like and has developed its antigen for the virus. It is likely you will not get sick from the same thing as severe the second time around.

Challenges to the Immune System  1. Allergies: a reaction to a harmless or common substance by the body’s immune system  Can be caused by many things such as food and medicines.  Symptoms range from runny nose and itchy eyes to more serious such as asthma.  Scientists believe allergies could be useful because the mucus traps and carries away possible infection.  1. Allergies: a reaction to a harmless or common substance by the body’s immune system  Can be caused by many things such as food and medicines.  Symptoms range from runny nose and itchy eyes to more serious such as asthma.  Scientists believe allergies could be useful because the mucus traps and carries away possible infection.

Challenges cont…  2. Autoimmune Diseases: a disease in which the immune system attacks the organisms own cells  In an autoimmune disease, the immune system cells mistake body cells for pathogens.  An example is rheumatoid arthritis, in which the immune system attacks the joints.  Other examples include diabetes, multiple sclerosis, and lupus.  2. Autoimmune Diseases: a disease in which the immune system attacks the organisms own cells  In an autoimmune disease, the immune system cells mistake body cells for pathogens.  An example is rheumatoid arthritis, in which the immune system attacks the joints.  Other examples include diabetes, multiple sclerosis, and lupus.

Challenges cont…  3. Cancer: a disease in which the cells begin dividing at an uncontrollable rate and become invasive.  Can be killed by Killer T cells, until the rate of reproduction of the cells becomes too much for the killer T cells.  Cancers invade nearby tissues and disrupt the normal activities of the invaded organ  If the reach the cardiovscular system they can be transported to any place in the body.  3. Cancer: a disease in which the cells begin dividing at an uncontrollable rate and become invasive.  Can be killed by Killer T cells, until the rate of reproduction of the cells becomes too much for the killer T cells.  Cancers invade nearby tissues and disrupt the normal activities of the invaded organ  If the reach the cardiovscular system they can be transported to any place in the body.

Challenges cont…  4. AIDS: the Human Immunodeficiency Virus (HIV) causes Acquired Immune Deficiency Syndrome (AIDS).  HIV infects the immune system directly.  Uses helper T cells as factories to produce more viruses. The helper T cells are destroyed during this process.  People with AIDS have very few helper T cells so nothing activates the B cells and killer T cells  People don’t usually die of AIDS itself, they die of the diseases that they cannot fight off  4. AIDS: the Human Immunodeficiency Virus (HIV) causes Acquired Immune Deficiency Syndrome (AIDS).  HIV infects the immune system directly.  Uses helper T cells as factories to produce more viruses. The helper T cells are destroyed during this process.  People with AIDS have very few helper T cells so nothing activates the B cells and killer T cells  People don’t usually die of AIDS itself, they die of the diseases that they cannot fight off

THIS IS THE END OF THE NOTES!!!!