Immune SystemImmune System

DiseaseDisease

A A diseasedisease is any change other is any change other than injury, that disrupts the than injury, that disrupts the normal functions of the body. normal functions of the body. Some diseases are inherited, Some diseases are inherited, others are caused by materials in others are caused by materials in the environment.the environment.

Still others are caused by Still others are caused by agentsagents such as such as bacteriabacteria, , virusesviruses, fungi, , fungi, animals such as worms, etc..animals such as worms, etc..

PathogensPathogens

Disease-causingDisease-causing agents such as agents such as bacteria are called bacteria are called pathogenspathogens. . (sickness makers)(sickness makers)

Diseases caused by pathogens Diseases caused by pathogens are called are called infectious diseasesinfectious diseases, , because the agents that cause because the agents that cause infectinfect the body they enter.the body they enter.

ToxinsToxins

ToxinsToxins are poisons that produce are poisons that produce illness by disrupting bodily illness by disrupting bodily functions.functions.

Some Some bacteriabacteria cause disease by cause disease by producing toxins and injecting producing toxins and injecting them into them into hosthost cells.cells.

AnimalsAnimals that carry disease-that carry disease-causing organisms from person to causing organisms from person to person are called person are called vectorsvectors..

AntibioticsAntibiotics

AntibioticsAntibiotics are compounds that are compounds that killkill bacteriabacteria without harming the cells of without harming the cells of humans or animals.humans or animals.

Antibiotics work by interfering with the Antibiotics work by interfering with the cellular processes of microorganisms.cellular processes of microorganisms.

They have They have no affectno affect on on virusesviruses Penicillin was discovered in 1928 by Penicillin was discovered in 1928 by

Alexander Alexander FlemingFleming.. http://www.biography.com/people/http://www.biography.com/people/

alexander-fleming-9296894alexander-fleming-9296894

VaccinesVaccines

Killed or weakened viruses.Killed or weakened viruses. The The injectioninjection of a weakened or of a weakened or

mild form of a pathogen to mild form of a pathogen to produce produce immunityimmunity is known as a is known as a vaccination.vaccination.

Today more than 20 serious Today more than 20 serious human diseases can be human diseases can be prevented by vaccinations.prevented by vaccinations.

https://www.youtube.com/watch?https://www.youtube.com/watch?v=y0opgc1WoS4v=y0opgc1WoS4

https://www.youtube.com/watch?https://www.youtube.com/watch?v=3aNhzLUL2ysv=3aNhzLUL2ys

First Line of DefenseFirst Line of Defense The body has several physical barriers:The body has several physical barriers:

An outer layer of intact skinAn outer layer of intact skin Hair in the nostrilsHair in the nostrils MucousMucous membranesmembranes CiliaCilia

Mucus in your nose or throat traps Mucus in your nose or throat traps viruses and bacteriaviruses and bacteria

Stomach acidsStomach acids and digestive and digestive enzymesenzymes destroy many pathogens.destroy many pathogens.

Mucus, saliva, sweat, tears contain an Mucus, saliva, sweat, tears contain an enzyme that breaks down the enzyme that breaks down the cell cell wallswalls of many of many bacteriabacteria..

CiliaCilia

Second Line of Second Line of DefenseDefense The The inflammatoryinflammatory response is a response is a

defense reaction to tissue damage defense reaction to tissue damage caused by injury or infection.caused by injury or infection.

White blood cells leak from the White blood cells leak from the vessels to enter the infected tissues. vessels to enter the infected tissues. They They engulfengulf and and destroydestroy bacteria.bacteria.

The infected tissue may become The infected tissue may become swollen and painful.swollen and painful.

The Immune ResponseThe Immune Response

If a pathogen is able to get past If a pathogen is able to get past the bodythe body’’s first few lines of s first few lines of defense the immune system defense the immune system reacts with a series of reacts with a series of specific specific defensesdefenses that attack disease- that attack disease-causing agents.causing agents.

A substance that triggers this A substance that triggers this response is called an response is called an antigenantigen..

White Blood Cells White Blood Cells

Leukocytes Leukocytes (White blood cells)(White blood cells) MacrophagesMacrophages

Lymphocyte (B cells, T cells, & Lymphocyte (B cells, T cells, & cytotoxic)cytotoxic)

Basophil (release of histamine Basophil (release of histamine and inflammatory response)and inflammatory response)

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Third Line of DefenseThird Line of Defense

AntibodiesAntibodies

– AntigensAntigens Are foreign substances that cause an Are foreign substances that cause an

immune response.immune response.

– AntibodiesAntibodies Are proteins found in blood plasma Are proteins found in blood plasma

that attach to one particular kind of that attach to one particular kind of antigen and help counter its effects.antigen and help counter its effects.

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Lock and Keywhat does that remind you

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Permanent ImmunityPermanent Immunity

Once the body has been exposed Once the body has been exposed to a pathogen, millions of to a pathogen, millions of memory B and T cells remain memory B and T cells remain capable of producing specific capable of producing specific antibodies to that pathogen.antibodies to that pathogen.

Immune System Immune System DisordersDisorders AllergiesAllergies result when antigens from result when antigens from

allergens (pollen, dust ball, dust mites) bind allergens (pollen, dust ball, dust mites) bind to a type of immune cells. The immune cell to a type of immune cells. The immune cell becomes activated and produces a chemical becomes activated and produces a chemical called histamine.called histamine.

HistaminesHistamines increase the flow of blood and increase the flow of blood and fluids to the surrounding area. They produce fluids to the surrounding area. They produce the sneezing, runny eyes and nose.the sneezing, runny eyes and nose.

AntihistaminesAntihistamines are drugs that are used to are drugs that are used to counteract the effects of histamines.counteract the effects of histamines.

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Autoimmune DiseaseAutoimmune Disease

When the immune system makes When the immune system makes a mistake and attacks the bodya mistake and attacks the body’’s s own cells, it produces an own cells, it produces an autoimmune disease.autoimmune disease.

A.I.D.S.A.I.D.S.

– HIV, the AIDS virusHIV, the AIDS virus Attacks helper T cellsAttacks helper T cells

– HIV has one of the fastest rates of HIV has one of the fastest rates of mutation of any pathogen ever mutation of any pathogen ever studied.studied.

– Drug-resistant HIV strains are now being Drug-resistant HIV strains are now being documented in newly infected patients.documented in newly infected patients.

– Exhibits how this virus readily adapts through Exhibits how this virus readily adapts through natural selection.natural selection.