Chapter 40 “The Immune System” 40.1 “Disease” 40.1 “Disease” Objective: Objective: Define the term “disease” Define the term “disease” Describe “Germ Theory”

Chapter 40 “The Immune Chapter 40 “The Immune SystemSystem””

40.1 “Disease”40.1 “Disease” Objective: Objective:

Define the term “disease”Define the term “disease”Describe “Germ Theory” & Describe “Germ Theory” & “Koch’s Postulates”“Koch’s Postulates”

Discuss disease Transmission & Discuss disease Transmission & Prevention.Prevention.

IntroductionIntroduction (Do not write) (Do not write)

How would you define an infection?How would you define an infection? Sickness, contamination of some sort.Sickness, contamination of some sort. By what?By what? Bacteria, or some “other” disease Bacteria, or some “other” disease

causing organism.causing organism. How does the human body become How does the human body become

infected?infected? Cuts, breathing, eatingCuts, breathing, eating

DiseaseDisease

A A diseasedisease is any change, other is any change, other than injury, that disrupts than injury, that disrupts “normal” body functions“normal” body functions..

Some are inherited Some are inherited (hemophilia), some are caused (hemophilia), some are caused by environment, others by by environment, others by bacteria, viruses, or fungi.bacteria, viruses, or fungi.

PathogensPathogens

Infect the bodyInfect the body Cause diseaseCause disease

VirusVirus

BacteriaBacteria

Malaria ParasiteMalaria Parasite

The Germ TheoryThe Germ Theory

Observations made by Louis Observations made by Louis Pasteur & Robert Koch concluded Pasteur & Robert Koch concluded that diseases were caused by that diseases were caused by “germs”, rather than “evil “germs”, rather than “evil spirits”.spirits”.

Koch developed guidelines to Koch developed guidelines to identify microorganisms that identify microorganisms that caused diseasescaused diseases

Agents of DiseaseAgents of Disease Ideal conditions for pathogen Ideal conditions for pathogen

growth - your body! growth - your body! Most are harmlessMost are harmless

Bacteria release toxins which Bacteria release toxins which make you sickmake you sick

Viruses (non-living) invade cells Viruses (non-living) invade cells and eventually cause them to pop and eventually cause them to pop

TransmissionTransmission Coughing, sneezing, physical Coughing, sneezing, physical

contact.contact. Contaminated food & water.Contaminated food & water. Infected animals.Infected animals. Vectors - animals that carry the Vectors - animals that carry the

disease causing organism (ticks, disease causing organism (ticks, mosquitoes)mosquitoes)

Fighting PathogensFighting Pathogens

PreventionPrevention Drugs Drugs Antibiotic – attacks cell Antibiotic – attacks cell

wall of bacteriawall of bacteria Do not work against Do not work against

viruses – no cell wallviruses – no cell wall

40.2 “The Body’s 40.2 “The Body’s Defense SystemDefense System””

Objective:Objective: Identify Non-Specific & Identify Non-Specific &

Specific Defenses.Specific Defenses. Define/describe the term Define/describe the term

Immunity.Immunity.

IntroductionIntroduction (do not write)(do not write)

With so many pathogens, why With so many pathogens, why aren’t you sick all the time?aren’t you sick all the time? Your body has a protective system; Your body has a protective system;

a series of defenses that guard a series of defenses that guard against disease.against disease.

Like walls that act as barriers & Like walls that act as barriers & security guards trained to spot security guards trained to spot invaders.invaders.

Immune SystemImmune System

Primary defense against Primary defense against pathogenspathogens

Nonspecific defensesNonspecific defensesBlock out everythingBlock out everything

Specific defensesSpecific defensesAttack a specific pathogenAttack a specific pathogen

Nonspecific DefensesNonspecific Defenses

First line of defenseFirst line of defense = = the skin, mucus, sweat, the skin, mucus, sweat, stomach acidstomach acid

Skin is the most Skin is the most important nonspecific important nonspecific defense.defense.

Inflammatory ResponseInflammatory Response Second line of non-specific Second line of non-specific

defensesdefenses Pathogens may enter body Pathogens may enter body

through a cutthrough a cut Area swells, gets redArea swells, gets red WBC released into injured areaWBC released into injured area Pathogens vs. WBC Pathogens vs. WBC

Inflammatory ResponseInflammatory Response

SkinWound

Bacteria enter the wound

WBCs move into the area and engulf the bacteria and cell debris

Capillary

Specific DefensesSpecific Defenses Powerful defense against a Powerful defense against a

“specific” pathogen.“specific” pathogen. S. defenses produce immunity S. defenses produce immunity

against pathogens.against pathogens. Two types of immunity: Anti-Two types of immunity: Anti-

body & Cell Mediated body & Cell Mediated Immunities.Immunities.

Antibody ImmunityAntibody Immunity Molecules on Molecules on

surface of surface of pathogens called pathogens called antigensantigens

Antigens trigger Antigens trigger immune responseimmune response

B cells (WBC) make B cells (WBC) make proteins called proteins called antibodies which antibodies which stick to antigens stick to antigens

VaccinesVaccines First vaccine was in late 1700s First vaccine was in late 1700s

against small poxagainst small pox Weakened pathogen is injected Weakened pathogen is injected

into bodyinto body Body mounts an immune response Body mounts an immune response

without getting sickwithout getting sick Immune system develops a memory of Immune system develops a memory of

the pathogen = permanent immunitythe pathogen = permanent immunity

Cell-Mediated ImmunityCell-Mediated Immunity

Powerful Immune System Powerful Immune System weapon = Killer T cell.weapon = Killer T cell.

Kill infected body cells.Kill infected body cells. Can cause transplantation Can cause transplantation

rejection.rejection. Helper T cells & Suppressor T Helper T cells & Suppressor T

cells.cells.

Immune DisordersImmune Disorders Two main types of disorders: Auto-Two main types of disorders: Auto-

Immune (overreaction) & Immune (overreaction) & Weakening of I.S. (AIDS).Weakening of I.S. (AIDS).

Allergies: overreaction to antigen Allergies: overreaction to antigen in environment.in environment.

Histamines are released = Histamines are released = inflammatory response.inflammatory response. AsthmaAsthma

Auto-Immune DiseasesAuto-Immune Diseases

Immune System attacks Immune System attacks body’s own cells.body’s own cells.

Ex - Rheumatoid arthritis Ex - Rheumatoid arthritis & Multiple sclerosis& Multiple sclerosis

HIV/AIDSHIV/AIDS

HIV attacks T HIV attacks T cellscells

Kills T cells = Kills T cells = kills immune kills immune systemsystem

New viruses leaving an New viruses leaving an infected T cellinfected T cell

40.3 “Cancer40.3 “Cancer””

Objective: Objective: Define Cancer.Define Cancer. Identify causes of Identify causes of

Cancer.Cancer.

CancerCancer

2nd leading cause of death in 2nd leading cause of death in U.SU.S

Cancer is uncontrollable cell Cancer is uncontrollable cell growth which forms malignant growth which forms malignant tumors.tumors.

Caused by mutations, or Caused by mutations, or changes in DNA.changes in DNA.

CausesCauses

VirusesViruses HPV is sexually HPV is sexually

transmitted and may transmitted and may lead to reproductive lead to reproductive cancers. cancers.

Hepatitis leads to Hepatitis leads to liver cancer.liver cancer.

Causes of Cancer...Causes of Cancer...

RadiationRadiation = UV light = UV light from the Sun.from the Sun.

ChemicalsChemicals = = carcinogencarcinogenGeneticsGenetics

Treatment: surgeries, Treatment: surgeries, chemotherapychemotherapy