+ Immune System and Disease Chapter 35. + What are the basics? Homeostasis Homeostasis is the ability of an organism to maintain a stable internal.

+

Immune System and DiseaseChapter 35

+What are the basics?

Homeostasis is the ability of an organism to maintain a stable internal environment.

Diseases can disrupt this stability.

Your immune system is the organ system that protects your body from disease.

Your body has three different lines of defense against pathogens, or disease causing agents.

+Infectious Diseases

Occurs when pathogens cause a physiological changes that disrupt normal body functions

Pathogens are disease-causing agents

Infectious diseases can be caused by:Viruses (non-living)BacteriaFungiProtistsParasites

+How do diseases spread ?

Coughing, Sneezing, Physical Contact Mostly infect the nose, throat and respiratory

tract

Exchange of body fluids Most sexually transmitted disease

Contaminated water/food Affect the digestive tract Diarrhea is one common symptom

Infected animals Mad cow disease, SARS, West Nile virus, bird

flu, etc

+What are the two types of immune defense?

The immune system includes two general categories of defense mechanisms against infection.

Nonspecific defenses guard against infections by keeping most things out of the body.

Specific defenses track down harmful pathogens that have managed to break throughthe body’s nonspecific defenses.

+The Body’s Defense Systems

INNATE Immunity

1st and 2nd lines of defense

1st defense: Skin Saliva, mucus, tears

2nd defense: Inflammatory

response

ACQUIRED Immunity

3rd line of defense

The body distinguishes between “self” and “foreigner”

Respond to particular pathogens

Non-Specific Defense Specific Defense

+Question Break:

Why do you think the 1st and 2nd defense are called innate and the

3rd defense called acquired?

HINT: Innate means “instinctual” or “born with” & acquired means to

obtain

+1st Line of Defense: Barriers to Infection

To cause disease, a pathogenmust invade the body.

Your body has barriers to keep this pathogens out.

Skin provides a protective barrier.

Mucous membranes line up interiorsurfaces that come into contact withthe environment.

Pathogens that are swallowedare likely to be destroyed byyour stomach acids.

Sweat and tears contains salts, acids,and enzymes that help kill pathogensin your skin and eyes.

+2nd Line of Defense: Inflammatory Response

The inflammatory response is the body’s responseto tissue damage.

As soon as pathogen enters your body, damaged tissue releases chemical signal (histamines).

Blood vessels expand. What is a consequence of this?

Plasma carries macrophages that engulf and destroy pathogens during phagocytosis

If infection persists, body may increasetemperatureresulting in a fever.Why?

+3rd Line of Defense: Immune Response (Acquired immunity) The immune response attacks specific

pathogens using specialized cells and proteins

Leukocytes: white blood cells (2 types):

1. T cells are white blood cells that attack and kill harmful bacteria.

2. B cells are white blood cells that make antibodies.

+Signaling the problem

An antigen is any foreign substance in the body and stimulates an immune response

An antibody is a Y-shaped protein that attaches to a specific antigen,

bind to the pathogen's membrane proteins

Acts as a flag for destruction weaken the pathogen’s membrane Made by B-cells

+Immune response has 2 styles of Action

1. Humoral ResponseSignaling responseActivates production of B-cells

2. Cell-Mediated ResponseDestruction responseActivates T-cell response

+

+The Story of Your Body’s Soldiers

An antigen of a pathogen attaches to an antibody of a B-cell

Helper T-cells activate B cells to grow and divide rapidly into1. Plasma B-cells

2. Memory B-cells (secondary response)

Plasma B-cells release more antibodies that mark antigens for destruction

+The Story of Your Body’s Soldiers

Helper T-cells bind to antigen and are activated to go and activate:1. More helper T-cells- to activate B cells

2. Cytotoxic T-cells

3. Produce Memory T-cells (secondary Response)

Cytotoxic T-cells Bind to infected cells containing antigen destroy infected cell

Puncture membrane Initiate apoptosis (cell suicide)

+Secondary Response- Memory B and T cells

The next time the same pathogen enters the body, the immune response is much

faster at fighting it because of the memory B and T cells

Memory B and T cells are already “trained” with the antibodies produced in the

primary response

Immunity: ability to resist diseasePossible because of memory B and T cells

+

+Homework

Outline chapter 35.1

+Immune System Day 2Fighting Infectious Diseases

+Bellringer- Review Specific Immune Response

http://highered.mcgraw-hill.com/sites/0072507470/student_view0/chapter22/animation__the_immune_response.html

http://www.sciencelearn.org.nz/Contexts/Fighting-Infection/Sci-Media/Animations-and-Interactives/The-immune-system

http://hippocampus.org/HippoCampus/Biology?loadLeftClass=CourseCombination&loadLeftId=9&loadTopicId=354

+How do we fight infectious disease when our immune system isn’t strong enough on its own?

CASE STUDY: Smallpox and Chicken Pox

Smallpox was once found throughout the world.

Caused illness and death wherever it occurred.

Smallpox spreads easily from one person to another.

People were once vaccinated against this disease.

+Case Study: Small Pox

The United States stopped giving the smallpox vaccine in 1972.

In 1980, the World Health Organization (WHO) recommended that all countries stop vaccinating for smallpox.

The vaccine is no longer given to the general public because the virus has been wiped out. Or has it?

+The last naturally occurring case of smallpox was diagnosed on 26 October 1977.

In ordinary type smallpox the bumps are filled with a thick, opaque fluid and often have a depression or dimple in the center.

Acquired ImmunityMore than 200 years

ago, the English physician Edward Jenner wondered if it might be possible to produce immunity against smallpox.

Jenner knew that people who had been affected by a mild disease called cowpox developed an immunity to smallpox.

Acquired ImmunityJenner took fluid from

one of the sores of a cowpox patient and put the fluid into a small cut that he made on the arm of a young farm boy named Jamie Phillips.

Two months later, he injected Jamie with fluid from a smallpox infection and …

The rest is history.

+Active Immunity and Vaccination

A Vaccination is the injection of a weakened or a similar but less dangerous form of a pathogenStimulates immune system with an antigen Body produces memory B and T cellsQuicken and Strengthen immune response

This is an example of Active ImmunityNatural exposure to antigen Deliberate exposure to antigen (Vaccine)

+ Vaccines Save Lives By Preventing Disease

Vaccine’s prevent the infection of a pathogen

There are vaccines for more than 20 serious human diseases

Not every disease has a vaccine

that we have discovered

+Passive Immunity

Diseases can be prevented also by injecting antibodies produced by other animals or individualsThis gives an individual temporary immunity Immune system eventually destroys foreign

antibody

Can also occurNaturally (through mother’s breast milk or

placental transfusion)Deliberately (injection)

+See the Difference?

Active Immunity

Inject a pathogen

Long-term immunity

Strengthens immune system

Passive Immunity

Inject antibodies

Short-term immunity

Temporarily defeats pathogen

Both can occur naturally or deliberately

+Antibiotics

Antibiotics drugs are those that can kill bacteria without harming the host Ex: Penicillium

They have NO effect on viruses Why? (hint- break down the word)

There are, however, antiviral drugs that can slow down viral activity Viruses are very difficult to get rid of Some never are able to leave your body

+New and Re-emerging Diseases

Why are infectious diseases changing? New Diseases coming from

ongoing merging of human and animal habitats

Misuse of medications Evolving resistance to drugs

http://wps.prenhall.com/esm_freeman_biosci_1/0,6452,499512-,00.html

+Immune System Day 3Immune System Disorders

+Misguided Immune Response

Sometimes an strong immune response to a harmless antigen will produce Allergies Asthma Autoimmune diseases

Harmless particles: pollen, dust mites, mold, pet dander, their own cells

+Allergies

Allergens: antigens that cause allergies

When an allergen enters the body, the inflammatory response is triggeredMast cells release histaminesSymptoms: rashes, sneezing,

watery eyes, runny nose

Antihistamines are drugs that relieve allergy symptoms

+AsthmaAllergic reaction in the respiratory

system Air passages narrow Causing short breath, wheezing,

coughing

Triggered by: Genetic predisposition Environmental factors Respiratory infections Exercise Emotional distress Cold/dry air Smoke, dust, pet dander, etc

+Autoimmune diseasesSometimes diseases occur where the

immune system fails to properly recognize “self” Attacks the own body’s cells or

compounds Thinks they are pathogens

Examples: Type I diabetes Rheumatoid Arthritis Lupus

Some treatments can alleviate symptoms and some suppress the immune response Sadly, there are no cures

+HIV/AIDS- Human Immunodeficiency

HIV- Human Immunodeficiency Virus The CAUSE of AIDS Known as a retrovirus Attacks the Helper T-Cells Becomes difficult for the immune

response to defend against diseases and pathogens

AIDS- Acquired Immunodeficiency Syndrome When the amount of T-cells in the

body is reduced to less than 1/6 normal count

+HIV and AIDS attacks the immune system

HIV/AIDS is not actually the killer itself directlyThe disease debilitates the

immune systemThe immune system can no

longer efficiently respond to pathogens it normally fights off

Causes opportunistic diseases- diseases that attack a person with a weakened immune system

+Spread and Prevention

Only transmitted through contact with Infected blood Semen Vaginal Secretions Breast milk

4 main ways it spreads:1. Sexual intercourse2. Shared needles3. Blood contact4. Mother-to-child (during

pregnancy, birth, breast-feeding

+Spread and Prevention

No-risk behavior includesSexual abstinence Intravenous drug-use abstinence

Many people do not know they have HIV/AIDS because they have not progressed far enough in the disease This is why it is so important to KNOW

a potential sexual partner EVERYONE being tested is essential to

stop the spread

+There is NO cure.

Currently there s no cure for aids

Only drugs that can help survive for some yearsVERY expensive

DEADLY misconception Just because there are

treatments, some people now believe AIDS is not serious

DEAD WRONGhttp://www.whitehouse.gov/admin

istration/eop/onap/nhas