AP Biology 2006-2007 Immune System WBC attacking cancer cell lymph system.

AP Biology

200

6-20

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Immune System

WBCattackingcancer cell

lymphsystem

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Vocabulary of Immunity

DiseaseAny condition that disrupts the homeostasis of an organism.

PathogenForeign organisms that cause disease. (microorganisms)

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1. Pathogens2. Toxins in the environment3. Inheritance… Gee thanks, mom!

What causes disease?

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Pathogens of DiseaseVirus Common Cold, Influenza, HIV, Chicken Pox, Measles

Bacteria Strep Throat, Syphilis, E-coli, Food Poising

Fungus Athletes foot, Ringworm

Parasites Leeches, Tapeworms, Malaria, Lyme Disease

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Other Causes of Disease

Cause of Disease

Examples

Inherited Disorders

Down Syndrome, Cystic Fibrosis, Sickle Cell Anemia, Type 1 Diabetes

Exposure to toxins

Exposure to asbestos -> MesotheliomaLead poisoning, radiation poisoning

Poor nutrition Scurvy, Blindness, Lack of Iodine (Goiter)

Organ malfunctions

Hear Attack, Diabetes, Stroke

High risk behaviors

Lung Cancer, Drug Addiction, Skin Cancer, STD’s

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HOW ARE DISEASES SPREAD?

Coughing Sneezing Physical Contact (Saliva, Blood, Bodily

Fluids, Skin Contact) Contaminated Food or Water Infected Animals (Vectors)

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To protect and defend the body against pathogens

The Immune System

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How does the Immune System Work?

2 ways:

1. Nonspecific defenses-

Tries to keep everything OUT! Skin, mucus, cilia, tears, stomach acid, saliva, sweat

2. Specific Defenses-

Fights off infection once the

pathogen gets inside the body. White Blood Cells (WBC’s)

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If the pathogen gets inside anyway, there are things your body usually does to try to slow the invader down…

1. Increased Body Fever: Denatures pathogen’s proteins

2. Expanding blood vessels: (red and warm)

Increased blood flow to area

= More RBC’s & clotting factors for repair

= More WBC’s to fight bacteria (pus)

Inflammation

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Antigen chemical name tags on the surface of every cell = Protein

The body recognizes invaders!

disease-causingbacteria

disease-causingvirus

one of yourown cells

antigens say:“I belong here”

antigens say:“I am an invader”

antigens say:“I am an invader”

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Some kill pathogens

Some produce antibodies

White Blood CellsAKA: leukocytes, lymphocytes, plasma cells, eosinophils, neutrophils, basophils,

monocytes, macrophages

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Patrolling B cells make antibodies against invader immediately

Memory B cells remembers invader can make antibodies

quickly the next time!

B cells

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Antibodies- proteins that either kill invaders or mark them for killing

Antibodies are SHAPE SPECIFIC to pathogens!

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B cells immune response

invader(foreign antigen)

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B cells

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Memory B cells

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Patrolling B cells

Make & release antibodies

recognition

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Antibody “fits” with antigen

Antibodies already in blood

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The antibody tag says “this is an invader” quick…eat him!

Antibodies:

macrophageeating tagged invaders

invading germs tagged with antibodies Y

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B cells releasing antibodies

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T Cells

Helper T Cells: Notifies other WBC’s of invasion! Killer T Cells: Hunts down pathogens & destroys them!

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1. Exposure to harmless

version of a pathogen

“dead”, weakened

Vaccinations

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2. Immune response produces antibodies to

mark and destroy the invading pathogen!

Antibodies = Shape Specific!!

3. Antibody production guarantees a rapid immune response if there is future exposure to the SAME pathogen!

Most successful against viral diseases Ex: flu, chicken pox, HPV, MMR, swine flu, whooping

cough, polio, small pox

Vaccinations

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Immunity

Immunity = the condition your body has when it already knows how to make the antibodies for a specific disease.

If you get sick with an illness and fight it off, you can’t get the same illness again

Pathogen is recognized! Helper T cells signal the immune system to respond!

B cells make antibodies. Killer T cells start killing!

Types of Immunity

Active Immunity Occurs when a organism is: 1. infected with a disease or 2. gets a vaccine

The organism makes it own antibodies specific to antigen

This type of immunity last a life time (stimulates B cells to make antibodies if re-exposed)

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Types of Immunity

Passive Immunity Antibodies made by another organism (not

you!)

Only last a short time (~1 month, your body will eventually destroy the borrowed antibodies)

Ex: Babies will receive antibodies from their mother when they breastfeed.

Ex: Travelers to foreign countries can get antibodies (injected) against tropical diseases.

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Curing You of Disease

Antibiotics = medicine

Ex: Penicillin, Streptomycin, Tetracycline.

Advantage kill bacteria that have successfully invaded you, without harming

your cells

Disadvantages use only after sick only good against bacteria possible development of resistance by bacteria

(if don’t use correctly) – ALWAYS TAKE THE ENTIRE Rx can get sick again by the same pathogen

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Disruption of Homeostasis…

Auto-Immune DiseasesImmune system attacks body cells

lupus antibodies attack many different body cells

rheumatoid arthritis antibodies cause damage to cartilage & bone

diabetes insulin-making cells of pancreas are attacked & destroyed

multiple sclerosis T cells attack myelin sheath of brain & spinal cord nerves fatal

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AllergiesThe response of the immune system to harmless environmental substances. (It thinks they are pathogens!)

Histamines are the chemicals released to cause the inflammatory response

Ex: Pollen can cause a fever, runny nose, and sneezing

Some allergies can trigger a severe reaction, called anaphylactic shock

This can cause choking due to a constricted airway

When things go wrong…

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Allergens

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Organ Transplants

People who are LIVING can donate a Kidney or a PART of THE:Lung, Liver, Intestine, Pancreas

Tissues that can be donated are:Cornea (coating of the eyeball), Middle ear, Skin, Heart valves, Bone, Veins, Cartilage, Tendons, Ligaments

Organs of the body that can transplanted after death:Kidneys, Heart, Liver, Pancreas, Intestines, Lungs, Skin, Bone marrow, Cornea

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Organ Transplants

When a person receives someone else's organ, the organ has foreign antigens on it.

The recipient’s white blood cells will recognize the organ as foreign, think it is a pathogen, and attack it. (Killer T!)

So, the recipient has to take

immunosuppressant drugs

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Organ Transplants

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HIV: Human Immunodeficiency Virus

Infects helper T cells Helper T cells can’t activate rest of immune system

The body doesn’t hear the alarm

AIDS:Acquired ImmunoDeficiency Syndrome

T cell count very low (200 cells/mm3 instead of the normal 500-1000)

infections by other (normal) pathogens can cause death

Disease of the Immune System

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HIV AIDS

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AIDS:fatigue

diarrheanauseavomiting

feverchills

night sweats

Death fromopportunistic

Infections

HIV/AIDSSymptoms

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HIV/AIDS

Over 33.4 million people are infected with

HIV/AIDS worldwide

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Transmission of HIV

Healthy skin is an excellent barrier against HIV and other viruses and bacteria.

HIV cannot enter the body through unbroken skin.

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Transmission of HIV