Micro lesson 5 Immune System

Micro lesson 5 - Lesson 5 Lesson Intro to MICROBIOLOGY DEA 1135 The human body is continually working to keep the internal environment in a

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Unformatted text preview: Lesson 5 Lesson Intro to MICROBIOLOGY DEA 1135 The human body is continually working to keep the internal environment in a condition of homeostasis. The system that wards off disease and provides resistance to foreign organisms is the immune system. Types of immunity Types There are two general types of immunity: natural and acquired. •Natural immunity is the immunity with which we are born. It is inherited and permanent, and it includes such first line barriers like the skin, mucous secretions and tears. •Acquired immunity is the reaction that occurs as a result of exposure to pathogen. It allows the body to create a way to recognize these pathogens again in the future. Key Elements Key Involved Involved In Acquired Immunity In Acquired immunity Acquired There are 2 types of acquired immunity. Active acquired immunity is the means by which the person’s body produces antibodies in response to a pathogen. This can be done naturally, by the person’s own body, or passively, by a vaccination. Passive acquired immunity is temporary immunity transferred from one person to another. This type of immunity has an immediate effect against the pathogen but is only temporary. It’s used to give the person’s body a chance to build it’s own protection against the infection. ACQUIRED IMMUNE RESPONSE ACQUIRED 3 CHARACTERISTICS: CHARACTERISTICS: 1. Self recognition 1. 2. Specificity Specificity 3. Memory 3. SELF RECOGNITION SELF Self Recognition continued: Self The The body has a mechanism to recognize and differentiate between foreign invaders foreign and “self” components. In In healthy, immune competent individuals, immune responses are not produced against “self” components. against SPECIFICITY SPECIFICITY Specificity continued: Specificity In In most instances, the body can only recognize the repeat invader and repeat specifically respond to it. Immunity Immunity to the measles virus, for example, does not provide immunity against the mumps virus. against MEMORY MEMORY Antigen Antibodies WBC Memory continued: Memory The The initial contact with an infectious antigen leaves an imprint of information. information The body can better and more quickly repel a later invasion by that same organism. organism. We rarely suffer twice from the same virus We i.e. - measles, mumps, etc. The first contact imprint “remembered immunity” so contact that the body repels the next invasion. that Vaccines are a synthetic or attenuated form of antigen (i.e.- a killed virus) used to stimulate the production of antibodies. Every Every time that antigen invades the body, the body remembers (from memory) and the appropriate antibodies are produced by the hosts white blood cells. by Some microorganisms are recognized as foreign material by the body, and contain chemical groups termed antigens. If an antigen bypasses the body’s other defenses, the immune system will produce a specific response, which is directed against that particular antigen. IMMUNOGLOBULINS IMMUNOGLOBULINS There There are five types of circulating antibodies five called immunoglobulins which are present in blood serum and secretions (such as saliva and tears). They are classified into categories based on They their structure and protein compositions. structure Each has its own distinct structure and Each function. function Immunoglobulin classifications include: Immunoglobulin G Immunoglobulin A Immunoglobulin M Immunoglobulin D Immunoglobulin E (IgG) (IgA) (IgM) (IgD) (IgE) IgG is the main immunoglobulin present in the blood and represents 70-75% of total immunoglobulin pool. In some humans, IgG crosses the placental barrier and is responsible for defense against infection in the first few months of a baby’s life. IgA provides localized antibody protection on mucosal surfaces. It is found in saliva, tears, sweat, nasal fluids, fluids of the lung and colostrum, genitourinary tract and gastro-intestinal tract. It is the primary defense against organisms attacking the exposed body surfaces. IgM is restricted to the bloodstream and is effective against microbes by binding with complement and causing agglutination and bacteriolysis. It is the first immunoglobulin to take part in the immune response and plays an important part in controlling viruses and bacteria in the bloodstream (bacteremia). IgD is a trace antibody and may be involved in stimulating and suppressing antibody producing cells to manufacture antibodies. AUTOIMMUNITY AUTOIMMUNITY Autoimmunity is when an individuals immune system Autoimmunity goes awry. It forms antibodies to its own tissues which destroy these tissues. destroy Also known as an autoimmune disorder. (i.e. Rheumatic fever – A person may get “strep” throat, which slightly alters heart tissue. Later strep infections can cause further heart damage. This is because the antibodies formed against the strep will also attack the altered heart tissue). Other autoimmune disorders include rheumatoid arthritis, Other multiple sclerosis, fibromyalgia, lupus, Crohn’s disease, etc. etc. HYPERSENSITIVITY HYPERSENSITIVITY Hypersensitivity occurs when the body’s immune system Hypersensitivity fails to protect itself against foreign material. Instead, the antibodies formed irritate certain body cells. irritate A hypersensitive or allergic individual is generally more hypersensitive sensitive to certain allergens than most people. (A few allergens common examples of allergens include grass, ragweed, pollen, foods, penicillin and other antibiotics, bee and wasp stings). wasp Such allergens stimulate antibody formation. The Such antibody antibodies bind to certain cells in the body, causing a characteristic allergic reaction. characteristic ANAPHYLAXIS ANAPHYLAXIS An An even more severe and sometimes fatal allergic reaction is called anaphylaxis or anaphylaxis anaphylactic shock. It is the result of an antigenanaphylactic antibody reaction that stimulates a massive antibody secretion of histamine. The individual may experience breathing The problems, headache, facial swelling, falling blood pressure, stomach cramps and vomiting. blood The antidote is an injection of either adrenaline The or antihistamine. If not attended quickly, death antihistamine If may result. may As As health care professionals we should always ask patients whether they are sensitive to any allergens or drugs. This precaution is necessary in order to This prevent negative and sometimes fatal fatal allergic responses to injected drugs. allergic In lesson 5, we have discussed the immune system and the body’s response to pathogens. We can conclude by saying, the immune system is both natural and acquired, as well as, active and passive. THE END THE Reading Assignment: Chapter 15 pp. 380-402 and Chapter 16 pp.403-446 ...
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This note was uploaded on 08/19/2011 for the course DEA 1135 taught by Professor Guilford during the Spring '05 term at Gulf Coast Community College.

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