The Immune The Immune SystemSystem

Chapter 9Chapter 9

Blue BookBlue Book

First Line DefensesFirst Line Defenses

These work against These work against all all harmful substances.harmful substances.

Unbroken skinUnbroken skin is a barrier is a barrier that prevents many that prevents many pathogens from entering the pathogens from entering the body.body.Skin’s secretionsSkin’s secretions, such as , such as perspiration or oil can be perspiration or oil can be acidic and prevent acidic and prevent pathogens from growing.pathogens from growing.

More First Line More First Line DefensesDefenses

Respiratory system uses Respiratory system uses ciliacilia and and mucusmucus to trap to trap pathogens. Mucus also has pathogens. Mucus also has an an enzymeenzyme that weakens that weakens the walls of some the walls of some pathogens.pathogens.

SneezingSneezing and and coughingcoughing expel expel some of the trapped some of the trapped pathogens.pathogens.

And even more first line And even more first line defenses!defenses!

Digestive systemDigestive system::SalivaSaliva – kills bacteria – kills bacteria

EnzymesEnzymes (from stomach, pancreas and (from stomach, pancreas and liver) kill pathogensliver) kill pathogens

Hydrochloride acidHydrochloride acid – kills some – kills some bacteria and stops the activity of bacteria and stops the activity of some viruses that enter the body from some viruses that enter the body from foodfood

MucusMucus – has a chemical that coats – has a chemical that coats bacteria and prevents it from binding bacteria and prevents it from binding to the inner lining of your digestive to the inner lining of your digestive organs.organs.

Yes, even more first line Yes, even more first line defenses!defenses!

Circulatory systemCirculatory system: White bloods : White bloods cells surround and digest foreign cells surround and digest foreign organisms and chemicalsorganisms and chemicalsFevers:Fevers: High temperatures slow High temperatures slow the growth of bacteria and the growth of bacteria and speeds up the body’s defenses.speeds up the body’s defenses.Inflammation:Inflammation: chemicals released chemicals released by damaged cells cause by damaged cells cause capillaries to expand, more blood capillaries to expand, more blood with more white blood cells to with more white blood cells to surround pathogens. surround pathogens.

Specific ImmunitySpecific Immunity

Molecules that don’t belong in Molecules that don’t belong in your body are called “your body are called “antigensantigens””Lymphocytes (white blood cells) Lymphocytes (white blood cells) respondrespond

Killer T cells release enzymes to Killer T cells release enzymes to destroy invadersdestroy invadersHelper T cells turn on the immune Helper T cells turn on the immune systemsystemB cells form antibodies that attach to B cells form antibodies that attach to the antigen and make it useless.the antigen and make it useless.Memory B cells remain in the body Memory B cells remain in the body and defend against another invasion and defend against another invasion by that same pathogen.by that same pathogen.

Active Immunity vs. Passive Active Immunity vs. Passive ImmunityImmunity

In active immunity your body In active immunity your body makes its own antibodies in makes its own antibodies in response to an antigen.response to an antigen.

In passive immunity, In passive immunity, antibodies that have been antibodies that have been produced in another animal produced in another animal are introduced into your are introduced into your body.body.

VaccinesVaccines

Vaccines are a form of the Vaccines are a form of the antigen that gives you active antigen that gives you active immunity against a disease.immunity against a disease.

Example: Measles vaccine is Example: Measles vaccine is injected into your body. Your injected into your body. Your body forms antibodies against body forms antibodies against the measles antigen. If you later the measles antigen. If you later encounter the same measles, encounter the same measles, the antibodies that are needed the antibodies that are needed are already in your bodyare already in your body

Infectious DiseasesInfectious Diseases

Louis Pasteur learned that Louis Pasteur learned that micro-organisms might cause micro-organisms might cause disease in humans. He also disease in humans. He also discovered that they could discovered that they could spoil wine and milk.spoil wine and milk.

He developed pasteurization He developed pasteurization – a process of heating a – a process of heating a liquid to a temperature high liquid to a temperature high enough to kill bacteria.enough to kill bacteria.

Koch’s RulesKoch’s Rules

Louis Pasteur knew bacteria Louis Pasteur knew bacteria caused disease, but he didn’t caused disease, but he didn’t know which bacteria caused know which bacteria caused a certain disease. Robert a certain disease. Robert Koch developed a way to Koch developed a way to isolate and grow one type of isolate and grow one type of bacteria at a time.bacteria at a time.

Keeping CleanKeeping Clean

Joseph Lister recognized the Joseph Lister recognized the relationship between infection relationship between infection rate and cleanliness. He rate and cleanliness. He dramatically reduced the dramatically reduced the number of deaths among his number of deaths among his surgery patients by washing surgery patients by washing their skin, his hands and his their skin, his hands and his instruments and bandages with instruments and bandages with carbolic acid. More and more of carbolic acid. More and more of his patients began to survive his patients began to survive surgery.surgery.

How Diseases are SpreadHow Diseases are Spread

A disease caused by a virus, A disease caused by a virus, bacterium, protist or fungus is bacterium, protist or fungus is spread from an infected organism or spread from an infected organism or the environment to another the environment to another organism.organism.

Direct contact with the infected Direct contact with the infected organism through water, air, food, organism through water, air, food, contact with contaminated objects contact with contaminated objects and by disease carrying organisms and by disease carrying organisms called biological vectors (dogs, rats, called biological vectors (dogs, rats, fleas, mosquitoes, birds, flies, etc.) fleas, mosquitoes, birds, flies, etc.)

Sexually Transmitted Sexually Transmitted DiseasesDiseases

Bacterial STD’s – gonorrhea, Bacterial STD’s – gonorrhea, chlamydia, and syphilis are all chlamydia, and syphilis are all caused by bacteria and may caused by bacteria and may be treated with antibiotics.be treated with antibiotics.Viral STD’s – herpes and HIV Viral STD’s – herpes and HIV are both caused by viruses. are both caused by viruses. The symptoms may be treated The symptoms may be treated by antiviral medications, but by antiviral medications, but there is no cure and no there is no cure and no vaccine.vaccine.

Noninfectious DiseasesNoninfectious Diseases

Allergies – an overly strong Allergies – an overly strong reaction of the immune reaction of the immune system to a foreign substance.system to a foreign substance.

Allergens – substances that Allergens – substances that cause an allergic response. cause an allergic response. These can cause hives, diarrhea, These can cause hives, diarrhea, runny nose, asthmarunny nose, asthmaYour immune system forms Your immune system forms antibodies and releases antibodies and releases chemicals call histamines the chemicals call histamines the promote red, swollen tissues.promote red, swollen tissues.

DiabetesDiabetes

A chronic disease associated A chronic disease associated with insulin levels.with insulin levels.

Type I – too little or no Type I – too little or no insulin production.insulin production.

Type II – body doesn’t Type II – body doesn’t properly process insulin.properly process insulin.

Chemicals and DiseaseChemicals and Disease

Chemicals that are harmful to Chemicals that are harmful to living things are called “toxins”living things are called “toxins”Toxins can cause birth defects, Toxins can cause birth defects, cell mutations, cancers, tissue cell mutations, cancers, tissue damage, chronic diseases, and damage, chronic diseases, and death.death.How much and for how long How much and for how long you take in a toxin determines you take in a toxin determines how it affects you.how it affects you.

CancerCancer

Uncontrolled cell growthUncontrolled cell growthCells do not function as part Cells do not function as part of your body.of your body.These cells take up space These cells take up space and interfere with normal and interfere with normal body functionsbody functionsCells travel through the body Cells travel through the body via blood and lymph vesselsvia blood and lymph vesselsProduce tumors anywhereProduce tumors anywhere

Causes of CancerCauses of Cancer

Smoking Smoking

Exposure to certain chemicals Exposure to certain chemicals called carcinogenscalled carcinogens

Exposure to X-rays, nuclear Exposure to X-rays, nuclear radiation and UV radiationradiation and UV radiation

Smoked or cured foodsSmoked or cured foods

Food additivesFood additives

Some virusesSome viruses

Genetic predispositionGenetic predisposition

TreatmentTreatment

Surgery to remove cancerous Surgery to remove cancerous tissuetissue

Radiation with X-rays to kill Radiation with X-rays to kill cancer cellscancer cells

Chemotherapy – the use of Chemotherapy – the use of chemicals to destroy cancer chemicals to destroy cancer cells.cells.

PreventionPrevention

Lifestyle choices:Lifestyle choices:No smokingNo smoking

No drinkingNo drinking

Healthy diet – limit fats, salt Healthy diet – limit fats, salt and sugarand sugar

Use sunscreen and limit Use sunscreen and limit sunlight exposuresunlight exposure

Careful handling of home and Careful handling of home and garden chemicalsgarden chemicals