Communicable Diseases Chapter 18 Communicable Diseases Lesson 2 The Body’s Defenses Against Infection Click for: >> Main Menu >> Chapter 18 Assessment Teacher’s notes are available in the notes section of this presentation. Next >>

A combination of body defenses made up of the cells, tissues, and organs that fight off pathogens and disease immune system Your body’s ability to resist the germs that cause a particular disease immunity Click to reveal the definitions. The body’s response to injury or disease, resulting in a condition of swelling, pain, heat, and redness inflammation

The white blood cells in the lymphatic system A secondary circulatory system that helps the body fight pathogens and maintain its fluid balance lymphocytes The white blood cells in the lymphatic system Click to reveal the definitions. antigen Any substance released by invading pathogens

Proteins that attach to antigens, keeping them from harming the body antibodies A preparation of dead or weakened pathogens that causes the immune system to produce antibodies vaccine Click to reveal the definitions.

In this lesson, you will learn to name the body’s first line of defense against pathogens. describe how the immune system functions. explain how antibodies protect the body. practice behaviors that keep your immune system healthy.

What is a barrier?

Your Body Defends Itself The Five Major Barriers Tears cover and protect the eyes from dust and pathogens. As they flow, tears carry foreign material away from the eye. Saliva Washes germs away from your teeth. It contains chemicals that kill pathogens trying to enter through your mouth. Skin provides a tough, outer protective surface that keeps pathogens from entering your blood. Most bacteria, viruses, and other pathogens never get a chance to make you sick because of your body’s natural barriers. Tears: Tears cover and protect the eyes from dust and pathogens. As they flow, tears carry foreign material away from the eye. Saliva: Saliva keeps pathogens from entering your blood If you get a cut, burn, or scrape, pathogens might get through this barrier. Skin: Skin provides a tough, outer protective surface that keeps pathogens from entering your blood. If you get a cut, burn, or scrape, pathogens might get through this barrier. Mucous membranes: Mucous membranes are the soft skin that lines the nose, mouth, eyes, and other body openings. They are coated with a sticky material called mucous that traps pathogens. Stomach acid: Stomach acid is a gastric juice produced by the lining of your stomach. It kills many of the pathogens that make it past the saliva and mucous membranes of your mouth. Mucous Membranes are coated with a sticky material called mucous that traps pathogens Stomach Acid It kills many of the pathogens that make it past the saliva and mucous membranes of your mouth

Your Body Defends Itself If a pathogen gets past one of the five major barriers, your body’s immune system takes over. 1. Immune system A combination of body defenses made up of the cells, tissues, and organs that fight off pathogens and disease

Your Body Defends Itself Your immune system has two main responses: 1) nonspecific response 2) specific response

Nonspecific Immune Response A. The nonspecific response begins with inflammation. Inflammation The body’s response to injury or disease, resulting in a condition of swelling, pain, heat, and redness The brain sends signals telling white blood cells to rush to the affected area and destroy pathogens. Circulation slows down. If pathogens multiply and spread, your body temperature may rise and cause a fever. A higher body temperature makes it harder for pathogens to reproduce. A fever also signals the body to produce more white blood cells to destroy the pathogens.

Nonspecific Immune Response With inflammation, the body starts producing a protein called interferon to stimulate the body’s immune system. The brain sends signals telling white blood cells to rush to the affected area and destroy pathogens. Circulation slows down. If pathogens multiply and spread, your body temperature may rise and cause a fever. A higher body temperature makes it harder for pathogens to reproduce. A fever also signals the body to produce more white blood cells to destroy the pathogens.

Specific Immune Response Each specific response is customized to attack a particular pathogen and its toxins. Once our immune system creates a specific response, cells from that response are ready to attack when the pathogen reappears. As a result, the second response is much quicker than the first.

Specific Immune Response Our immune system can “recognize” pathogens it has already battled. Once our immune system creates a specific response, cells from that response are ready to attack when the pathogen reappears. As a result, the second response is much quicker than the first.

Your Body Defends Itself Together, these responses provide immunity. Immunity- Your body’s ability to resist germs that cause a particular disease

The Lymphatic System and Circulatory System The circulatory system has blood as its main fluid and the lymphatic system has lymph as its main fluid.

The two types of lymphocytes are B cells and T cells. The Lymphatic System The two types of lymphocytes are B cells and T cells. Lymphocytes The white blood cells in the lymphatic system White blood cells help to destroy the infection in the body!

Lymphocytes B cells form in the bone marrow. T cells develop in the thymus gland.

Antibodies and Antigens Lymphocytes react to antigens. Antigen Any substance released by invading pathogens

The immune system responds to antigens by producing antibodies. Antibodies Proteins that attach to antigens, keeping them from harming the body

B Cells B cells produce a specific antibody for each specific antigen. Helper T cells activate the production of B cells. Killer T cells attach to invading pathogens and destroy them.

T Cells T cells either stimulate the production of B cells or attack pathogens directly. The two types of T cells are helper cells and killer cells. Helper T cells stimulate the production of B cells. Killer T cells attach to pathogens directly and destroy them.

Everyone is born with some natural immunity. Breast Feeding, if able, helps stimulate a baby’s natural immunity Immunity also develops when a vaccine is used. Before a baby is born, the mother’s antibodies pass from her body to her developing fetus. After a baby is born, antibodies are passed on to the baby through the mother’s milk.

What is a Vaccine? A vaccination is a fancy word for a shot. Vaccine A preparation of dead or weakened pathogens that causes the immune system to provide antibodies

Immunity To keep your body healthy, it is important to keep vaccinations current. Vaccines protect not only you but those around you. Vaccines have been developed for many diseases, such as polio, measles, and chicken pox. Some vaccinations, such as those for hepatitis B, must be given in a series over a span of a few months. Other vaccinations, such as the tetanus shot, must be given repeatedly during your lifetime. Vaccines have been developed for many diseases, such as polio, measles, and chicken pox. Some vaccinations, such as those for hepatitis B, must be given in a series over a span of a few months. Other vaccinations, such as the tetanus shot, must be given repeatedly during your lifetime.

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Lesson 2 Review What I Learned Vocabulary Define the term antigen. Name two types of white blood cells your immune system produces to fight antigens. An antigen is any substance released by invading pathogens. B cells and T cells.

Lesson 2 Review What I Learned Recall What is the lymphatic system? How does it protect your body against disease? a secondary circulatory system that fights pathogens and maintains fluid balance

Lesson 2 Review What I Learned Explain What is the body’s first line of defense against pathogens? Circulation to the area slows down. The body produces a protein called interferon that stimulates the immune system. Body temperature may rise making it harder for pathogens to reproduce.

Thinking Critically Analyze How does a fever help fight an infection? Lesson 2 Review Thinking Critically Analyze How does a fever help fight an infection? Pathogens reproduce at the body's normal temperature. When your body temperature rises even a little, it is harder for pathogens to reproduce. A fever also signals the body to produce more white blood cells.

Lesson 2 Review Thinking Critically Evaluate How do vaccines help protect the health of the community? Vaccines help protect individuals from getting certain communicable diseases, thereby reducing the spread of disease to the greater community.

Communicable Diseases End of Chapter 18 Communicable Diseases Lesson 2 The Body’s Defenses Against Infection Click for: >> Main Menu >> Chapter 18 Assessment