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Chapter 43 Warm-Up Define the following terms:
Pathogen Antigen Antibody Allergen Vaccine What are lymphocytes? Where do B cells and T cells mature?
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Ch. 43 Review Warm-Up What is the difference between innate vs. adaptive immunity? Contrast the functions of B cells and T cells. How are antigens recognized by immune system cells? What are memory cells? How does HIV affect the immune system?
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DEFENSE! Immunology (Immunology: the scientific study of the way the immune system works in the body, including allergies, resistance to disease, and acceptance or rejection of foreign tissue
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Why do organisms need an immune system?
Protection from external pathogens (ex: bacteria, viruses, fungi, and parasitic protists) Enter the body through the following routes: digestive system, respiratory system, urogenital system, or a break in the skin) Travel through the body using the following transport systems: circulatory system and lymphatic system Protection from internal attack by abnormal human body cells (ex: cancer cells)
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Why an immune system? animals must defend themselves against invaders
VIRUSES HIV, flu, cold, measles, chicken pox, SARS BACTERIA pneumonia, meningitis, tuberculosis FUNGI Yeast, athletes foot PROTISTS amoeba, Lyme disease, malaria cancer cells mutated body cells
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What organs and tissues are considered part of the human immune system?
Lymph vessels = tubes that run parallel to the circulatory vessels (arteries and veins) and serve as a blood filtration system to remove foreign particles Lymph nodes = oval shaped organs in the armpits, neck, etc. that are connected to lymph vessels ; they collect foreign particles and store B and T lymphocyte cells Spleen = stores blood cells ; removes clumped pathogens coated with antibodies from the blood stream
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What organs and tissues are considered part of the human immune system?
Adenoids (aka tonsils) = trap pathogens Bone Marrow = stem cells within the bone marrow differentiate into blood cells ; location where the B lymphocytes (aka B cells) mature Thymus = organ in the neck that is used to create and promote maturation of T lymphocytes (aka T cells)
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These are the parts of the immune System
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What defenses are most organisms born with?
Plants and all animals have nonspecific (aka innate/natural) immune responses that they are born with ; these responses attack any pathogen that tries to invade the body in the same way Example in Plants: Hypersensitivity response (cells that come in direct contact with the pathogen undergo apoptosis and signal other nearby cells to improve defenses in their cell walls)
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What defenses are most organisms born with?
Examples in Humans: First Line of Defense: External Barriers Physical Barriers: Skin; mucous membranes in the eyes, nose, anus, etc ; cilia lining the respiratory tract (sweep out pathogens) Chemical Barriers: Sweat (pH 3-5), tears + saliva (contain an enzyme called lysozyme that digests bacterial cell walls), stomach acid (hydrochloric acid is at pH 2)
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What defenses are most organisms born with?
Second Line of Defense: Internal Barriers Leukocytes (phagocytic white blood cells that “swallow” any foreign particle) Ex: Macrophages The Inflammatory Response: -cells release histamine (causes dilation / widening of blood vessels) -increased blood supply to the injury causes redness, warmth, and swelling -blood brings leukocytes to the area to “swallow” and digest pathogens
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What defenses are most organisms born with?
-Fever = widespread inflammatory response; higher body temperature interferes with bacterial and viral activity When a local response is not enough full body response to infection raises body temperature higher temperature helps in defense slows growth of germs helps macrophages (white blood cells) speeds up repair of tissues
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The first line of defense! Broad "external" defense
Physical Barriers non-specific defense external barriers skin & mucus membranes excretions sweat stomach acid tears mucus saliva “lick your wounds”
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The first line of defense! Broad "external" defense
Mucous Membranes Mucous membranes line the interior surfaces of our bodies Secrete mucous, a sticky fluid that traps pathogens Respiratory and digestive tract mucous membranes delivers pathogens to the stomach where they are killed Urinary and reproductive mucous membranes pass pathogens out of the body Skin Did you know that skin is the largest and most important organ in the human body? Provides a physical barrier to pathogens Releases sweat, oil, and waxes which contain chemicals that kill many pathogens
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Second line of defense…
Patrolling white blood cells attack invaders that get through the skin recognize invader by reading antigen surface name tag phagocyte cells macrophages “big eaters”
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Second line of defense…
Non-specific immunity includes: Inflammatory response Temperature response Proteins Just like the first line of defense (skin and mucous membranes), non-specific immunity is non-specific OR it works the same way against any and all pathogens
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Why do injuries swell? Inflammation
injured cells release chemical signals called Histamines increases blood flow brings more white blood cells to fight bacteria brings more red blood cells & clotting factors to repair
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Inflammatory response
Proteins: Complement proteins circulate in the blood system and kill pathogens when they encounter them. Interferons are proteins that are released by cells infected with a virus to warn nearby cells and help them get ready to resist viral infection
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What defenses do organisms develop throughout their lifespan?
Vertebrates have specific (aka acquired) immune responses that they develop over time in response to encounters with specific pathogens Third Line of Defense
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What defenses do organisms develop throughout their lifespan?
Example in Humans: A specific type of macrophage called an antigen – presenting cell (aka APC), which is part of the innate immune system, swallows an antigen released by a pathogen, chops it up, and presents it on its cell surface (Antigen = a molecule (usually a protein or carbohydrate) found on the surface of a pathogen or released by a pathogen that triggers the production of specific immunity molecules called antibodies) The APC binds with a helper T cell, which initiates the specific immune response
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What defenses do organisms develop throughout their lifespan?
Helper T cells trigger the differentiation of several types of lymphocytes (specific types of leukocytes, or white blood cells) B lymphocytes (aka B cells) – come in two forms, plasma B cells and memory B cells -plasma B cells actively make antibodies to bind to the antigen presented by the original APC -Antibodies = Y shaped proteins with tips that bind specifically to a particular antigen and cause clumping of multiple antigens; this clumping signals a macrophage to swallow the clump and digest it -memory B cells are made to prevent an infection by the same pathogen years later; they can be converted quickly into plasma B cells -B cells are part of Humoral Immunity (regulates destruction of “naked” pathogens in the body fluids – blood, saliva, tears, etc.—that have not yet infected a body cell)
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B-cells develop in the Bone Marrow
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What defenses do organisms develop throughout their lifespan?
T lymphocytes (aka T cells, cytotoxic T cells, or killer T cells) – come in two forms, active cytotoxic T cells or memory cytotoxic T cells -active cytotoxic T cells bind to the antigens displayed on infected body cells and release perforins (protein molecules) to break open the pathogens cell membrane and induce cell death -memory cytotoxic T cells are made to prevent an infection by the same pathogen years later ; they can be converted quickly into active cytotoxic T cells -Cytotoxic T cells are part of Cell-Mediated Immunity (regulates destruction of body cells that have been infected by a particular pathogen)
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T-Cells – develops in Thymus
Gland on Your Heart! How Romantic
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Why can’t humans “catch” the same infection twice?
Memory B and cytotoxic T cells can quickly develop into plasma B cells and active cytotoxic T cells to rapidly eradicate a pathogen recognized by the body This is called the secondary immune response.
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A question released on the 2013 AP Biology practice test that relates to the secondary immune response. An individual’s humoral response to a particular antigen differs depending on whether or not the individual has been previously exposed to that antigen. Which of the following graphs properly represents the humoral immune response when an individual is exposed to the same antigen more than once?
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What is the difference between passive and active immunity?
Active immunity involves an individual making his/her own antibodies, which are long-lasting -Natural = antibodies produced by B cells in response to infection by a particular pathogen -Artificial = antibodies produced by B cells in response to a vaccine (weakened / killed antigen) Exposure to harmless version of germ stimulates immune system to produce antibodies to invader rapid response if future exposure
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Jonas Salk 1914 – 1995 Developed first vaccine against polio
April 12, 1955 Poliomyelitis (polio) is caused by a virus that enters the body through the mouth. The virus multiplies in the intestine and invades the nervous system. It can cause total paralysis in a matter of hours. One in 200 infections leads to irreversible paralysis. Among those paralyzed, 5-10 percent die when their breathing muscles are immobilized. Polio mainly affects children under age 5. Poliomyelitis (polio) is caused by a virus that enters the body through the mouth. The virus multiplies in the intestine and invades the nervous system. It can cause total paralysis in a matter of hours. One in 200 infections leads to irreversible paralysis. Among those paralyzed, 5-10 percent die when their breathing muscles are immobilized. Polio mainly affects children under age 5.
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Polio epidemics 1994: Americas polio free
1916 The first major polio epidemic strikes in the United States; 27,000 people suffer paralysis and 6,000 die. Increasing numbers of outbreaks occur each year. 1921 Franklin D. Roosevelt is diagnosed with polio. 1928 Iron lungs are introduced to help patients with acute polio breathe. 1932 Franklin D. Roosevelt is elected President of the United States 1949 Dr. John Enders, Dr. Frederick Robbins and Dr. Thomas Weller develop a way to grow poliovirus in tissue culture, a breakthrough that aided in the creation of the polio vaccine. Their work earned the three scientists the Nobel Prize in physiology and medicine in 1954. 1952 The United States reports 57,628 polio cases -- the worst U.S. epidemic on record. 1979 The last U.S. case of polio caused by wild poliovirus is reported. 1988 Worldwide, polio continues to affect some 350,000 people in 125 countries. 1994 The Americas are certified polio-free. 2000 The Western Pacific region is certified polio-free. 2002 Europe is certified polio-free.
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Protecting you from disease
Vaccinations advantage don’t get illness long term immunity produce antibodies for life works against many viruses & bacteria disadvantage not possible against all invaders
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What is the difference between passive and active immunity?
Passive immunity involves antibodies being transferred from another organism, which are short-lasting -Natural = mothers pass antibodies to their fetus via the placenta and newborn via breast milk -Artificial = antibodies produced by a mouse in response to a pathogen can be injected into human tissue to protect against the same pathogen
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Koch's Postulate Dr. Robert Koch – first person to establish a clear procedure for identifying pathogens that cause infectious disease He studied anthrax (a common cattle disease that could be passed to humans)
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Why is HIV so harmful to the human body?
HIV = human immunodeficiency virus The HIV virus attacks the body’s Helper T cells, so that the body cannot create new cytotoxic T cells or B cells to fight against other, unrelated infections (ex: pneumonia, tuberculosis) When the Helper T cell count drops below 200 cells per cubic millimeter of blood, a patient has AIDS (acquired immunodeficiency syndrome) ; normally, a healthy individual’s T cell count ranges from 500 to 1800 cells per cubic millimeter of blood So in other words, HIV is the virus that causes the condition AIDS People who have AIDS typically die due to an inability to fight off other infections
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What are autoimmune diseases?
Autoimmune diseases occur when the T cells and B cells fail to recognize the body cells as “self cells” and attack them as they would a pathogen Ex: Auto-immune diseases - immune system attacks own cells psoriasis lupus antibodies attack many different body cells rheumatoid arthritis antibodies causing damage to cartilage & bone Type 1 diabetes insulin-making cells of pancreas attacked & destroyed multiple sclerosis T cells attack myelin sheath of brain & spinal cord nerves fatal
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Curing you of bacterial disease
Antibiotics = medicine advantage kill bacteria that have successfully invaded you make you well after being sick disadvantage use only after sick only good against bacteria possible development of resistance by bacteria (if don’t use correctly) can get sick again
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Immune system malfunctions
Allergies over-reaction to harmless compounds allergens proteins on pollen proteins from dust mites proteins in animal saliva body mistakenly thinks they are attackers
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