A combination of body defenses made up of the cells, tissues, and organs that fight off pathogens and disease • immunesystem Your body’s ability to resist the germs that cause a particular disease • immunity The body’s response to injury or disease, resulting in a condition of swelling, pain, heat, and redness • inflammation
A secondary circulatory system that helps the body fight pathogens and maintain its fluid balance • lymphaticsystem The white blood cells in the lymphatic system • lymphocytes Any substance released by invading pathogens • antigen
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
In this lesson, you will learn to • namethe body’s first line of defense against pathogens. • describehow the immune system functions. • explainhow antibodies protect the body. • practicebehaviors that keep your immune system healthy.
Sequencing Draw a concept map that shows different ways your body works to defend itself from pathogens entering your body. Use Figure 18.2 as a guide. Body’sDefenses
Your Body Defends Itself The Five Major Barriers Saliva Washes germs away from your teeth. It contains chemicals that kill pathogens trying to enter through your mouth. Tears cover and protect the eyes from dust and pathogens. As they flow, tears carry foreign material away from the eye. Skin provides a tough, outer protective surface that keeps pathogens from entering your blood. Stomach Acid It kills many of the pathogens that make it past the saliva and mucous membranes of your mouth MucousMembranes are coated with a sticky material called mucous that traps pathogens
Your Body Defends Itself If a pathogen gets past one of the five major barriers, your body’s immune system takes over. 1. Immune systemA 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. InflammationThe body’s response to injury or disease, resulting in a condition of swelling, pain, heat, and redness
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.
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. • What is a trick from Survivor or Project Runway to remember what immunity means? 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 lymphas its main fluid.
The Lymphatic System The two types of lymphocytes are B cells and T cells. LymphocytesThe 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. AntigenAny substance released by invading pathogens
The immune system responds to antigens by producing antibodies. AntibodiesProteins that attach to antigens, keeping them from harming the body
What does the word antibodies sound like? • What do antibiotics do to help us feel better? • Are antibodies the good or bad part of the infection? (GOOD !)
B Cells • B cells produce a specific antibody for each specific antigen.
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.
Immunity • 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.
What is a Vaccine?A vaccination is a fancy word for a shot. VaccineA 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.
Lesson 2 Review What I Learned VocabularyDefine the term antigen. Name two types of white blood cells your immune system produces to fight antigens.
Lesson 2 Review What I Learned RecallWhat is the lymphatic system? How does it protect your body against disease?
Lesson 2 Review What I Learned ExplainWhat is the body’s first line of defense against pathogens?
Lesson 2 Review Thinking Critically AnalyzeHow does a fever help fight an infection?
Lesson 2 Review Thinking Critically EvaluateHow do vaccines help protect the health of the community?
End of Chapter 18 CommunicableDiseases Lesson 2 The Body’s DefensesAgainst Infection Click for: >> Main Menu >> Chapter 18 Assessment