The Immune System: Your Defense Against Diseasemoodle.monashores.net/.../0/Microsoft_PowerPoint_-_Immune_Syste… · Immune System: body’s primary defense against disease-causing

The Immune System:Your Defense Against Disease

Terms:

Immune System: body’s primary defense against disease-causing microorganisms.

Immune: condition in which a body is able to permanently fight a disease.

Disease: any change, other than an injury, that interferes with the normal functioning of the body.

Pathogen: disease-causing microorganisms—viruses, bacteria, fungi, & protozoans.

Infection: condition that results when the body is successfully invaded by a pathogen.

I. Two parts of the Immune System:

A. Nonspecific defenses

1. Generalized; not directed at a specific pathogen, but all pathogens.

http://www.ehponline.org/members/2004/112-1/pathogens.jpg

2. First line of defense against pathogens:

a. Skin: Pathogens must penetrate the layers of dead skin cells in order to get inside the body.

1) Oil & sweat glands, produce an acidic environment killing many microorganisms.2) When cut; microorganisms can penetrate causing infection.

b. Respiratory Defenses: cilia, mucous, & hairs

c. Mouth: Saliva

d. Stomach: gastric fluids (acidic)

http://www.mypharmacy.co.uk/health_information/topics/m/mouth_problem/mouth.jpg

3. Inflammatory response: 2nd line of defense

a. Bacteria in a wound are attacked by white blood cells (leukocytes).

http://www.affordablehousinginstitute.org/blogs/us/white_blood_cell_among_red_small.jpg

b. If the infection remains small and in one place, a reddish swollen area develops (“inflamed”).

c. Fever is sometimes produced, which often slows or stops the growth of such microorganisms.

http://www.nuigalway.ie/postgrad/go4th/images/MHE_070.jpg

B. Specific Defenses:

1. If the nonspecific defense fails, a series of specific defenses attack the disease-causing agent. (A specific antibody will only attack a specific antigen.)

http://www.hepatitis-c.de/bilder/antigen.jpg

2. Examples: antibodies, T & B cells (specialized leukocytes).

3. Leads to permanent immunity.

http://www.lbl.gov/Publications/Currents/Archive/view-assets/Oct-03-2003/t-cell2.jpg

II. Vaccinations:

A. The injection of a weakened or mild pathogen to produce immunity.

B. Rabies1. Fatal virus.2. Transmitted through the bite of an animal.

http://www.amarilloanimalcontrol.com/images/dog_bite.jpg

C. Polio (1955)

1. Caused by 3 different viruses that attacks the nervous system, specifically the motor neurons.

2. Most common among children.

http://www.immune.org.nz/site_resources/Professionals/Diseases/Polio/Polio.jpg

III. Immune System Disorders:

A. Allergies:1. Overreaction of the immune system.2. Antigens cause the release of histamines.

http://www.guysandstthomas.nhs.uk/resources/Image/P/paediactricallergy/PaedAllergy_Sneeze.jpg

3. Histamines: increase flow of blood & fluids to infected area, resulting in sneezing, runny nose, itchy eyes, etc…

B. Asthma: respiratory disease; often arises b/c of allergies; smooth muscle in airways contract, limiting airflow, thus breathing becomes difficult.

http://www.bbc.co.uk/health/images/300/asthma_inhaler.jpg

IV. Transmission and Agents of Disease:A. Disease Transmission:

1. Entrance into the body (cut, wound).

a. Tetanus or lockjaw-- caused by bacterium Clostridium tetani, present in soil. b. Symptoms: fever, muscle spasms, even death.

http://www1.peterson.scu.k12.ca.us/~babad/thermometer.jpg

2. Coughing/sneezing a. Cold, measles, mumps,

influenza

3. Contaminated water or food

4. Infected animalsa. Ticks, mosquitoes

5. Sexual contact

http://www.img.uni-karlsruhe.de/download/aqul05_02.jpg

1. Viruses a. Contain RNA, and can be enclosed in a membrane

b. Are able to invade almost any type of livingorganism.

http://www.armageddononline.net/image/virus1.JPG

B. Types of Pathogens

c. Must invade a living cell � by attaching to the cell’s surface, then inserting its genetic material into the cell, enabling the virus to replicate or reproduce (i.e. HIV, smallpox, measles, polio).

http://www.uwosh.edu/departments/biology/shors/textbook/images/smallpox.jpg

2. Bacteriaa. Most are harmless

to humans.

b. Treatment: antibiotics

c. Ex. Strep throat

d. Lyme Disease

1. Caused by ticks that carry a bacterium.

http://www.nlm.nih.gov/medlineplus/ency/images/ency/fullsize/19617.jpg

2. Rash will develop near tick bite (bulls eye)

3. Symptoms: headache, fever, fatigue, pain in joints and muscles.

4. Spread most commonly by deer, but found in the outdoors

5. Present in Michigan

http://www.eurekaspringswest.com/images/deer%20&%20fawns,small.jpg

Lyme Disease cont.

3. Fungi

a. Most do not cause disease.

b. Most common fungal infections are those of the skin (i.e. types of ringworm; such as athlete’s foot-rough, irritable patches on the toes.

http://www.nlm.nih.gov/medlineplus/ency/images/ency/fullsize/2468.jpg

4. Protozoans

a. More than 30 different species.

b. Most serious infections are caused by those found in tropical regions(warm and moist).

http://ebiomedia.com/stock/images/ciliarray.jpg

c. Infections caused by protozoans: 1) Malaria (Diagram on page 388)2) Caused by protozoan Plasmodium, which lives in the blood.

3) Spread by mosquitoes.http://content.answers.com/main/content/wp/en/thumb/e/e9/400px-Anopheles_albimanus_mosquito.jpg

5. Other Infections

a. Tapeworm: pg. 5751) Parasitic flatworm. (What phylum?) 2) Absorbs digested food from the host’s intestine.3) Adult can be up to 18 meters long.

http://www.dogbreedinfo.com/images14/TapewormImg_1395.jpg

4. We get them from eating raw or incompletely cooked meat (beef).

5. Almost never kills the host, but do use up a lot of food� hosts may lose weight and become weak.

http://images.inmagine.com/168nwm/mixa/mx031/mx031013.jpg

b. Hookworm: pg. 577

1) Serious human intestinal parasite.2) Burrow into human skin and enter the bloodstream through an unprotected foot.3) Travel through the bloodstream, lungs, throat, and attach to our intestines.4) ¼ of the world may be infected.

http://www.humanillnesses.com/original/images/hdc_0001_0002_0_img0135.jpg