1. The Immune System

2. Immune System
Your immune system is your body’s defense against pathogens.
Pathogens = disease causing agents.
A disease is any condition that disrupts the normal functioning of the body.
Two types of Diseases:
Infectious Diseases
Noninfectious Diseases

3. Infectious Diseases
Infectious Disease - diseases that are caused by pathogens; microorganisms, viruses and parasitic worms and can be spread.
use the host’s resources for food and reproduction and create an infection inside the host’s body.
Two Types:
Bacterial and Viral

4. Noninfectious Diseases
Noninfectious Disease – diseases not caused by a pathogen and can’t be spread.
Stroke – disease of the circulatory system
Asthma – disease of the respiratory system
Cancer – uncontrolled multiplication of cells
Diabetes – Inability to control sugar levels
Each disease has its own characteristic pattern of symptoms and signs.
Doctors ask about the symptoms before they recommend an effective treatment.

5. Transmission of Pathogens
Pathogens move from host to host in many ways:
Person to person
Coughing, sneezing, kissing, shaking hands
Animal to person
bite
Nonliving thing to person
Desks, phones, papers, water fountains
If a disease is widespread and affects a large number of people it is considered an epidemic.
Bubonic plague – killed more than 25 million people in Europe during the 14th century.

6. Pathogens and Disease Type of Pathogen Diseases Caused Bacteria
Food poisoning, strep throat ,sinus infection , plague
Virus
Cold, influenza, pneumonia, AIDS, chicken pox, rabies
Protozoan
Malaria, diarrhea, dysentery
Fungus
Athlete’s foot, ringworm
Animal (worm)
Tapeworm, hookworm

7. Medicine and Disease Louis Pasteur – (1822-1895)
French chemist and biologist
Famous for developing the “germ theory”
Pathogens cause diseases.
library.thinkquest.org/
Louis Pasteur & Pasteurization – movie (2:51min)

8. Medicine and Disease Sir Alexander Fleming – (1881-1955)
Scottish biologist and pharmacologist
Famous for discovering – the antibiotic penicillin
Kills bacteria cells and has saved millions of lives.
nobelprize.org/

9. Nonspecific Defense System
System that keeps foreign cells out of the body tissue and destroys them if they do get inside.
Not specific to one certain invader by fights all possible invaders.
2 Lines of Defense:
Barriers
Inflammatory Response

10. 1st Line of Defense - Barriers
Skin
Largest organ of the body
Keeps body fluids in
Keeps foreign materials out
Conditions:
Dry and acidic
Sweat & Oil contain proteins that disrupt bacterial cell walls.

11. 1st Line of Defense - Barriers
Mucous Membranes
If pathogens make it past the skin and enter the body.
Easiest points of entry: eyes, nose and mouth
Conditions:
Mucous - Sticky liquid
Trap foreign particles.
Cilia - tiny hairs
sweep particles toward throat to be coughed out or swallowed.

12. 2nd Line of Defense Inflammatory Response - If the first line fails
Cells at the site of damaged area release chemicals that create an inflammation
Swelling, redness, heat & pain
Processes:
Blood vessels expand allowing fluid to leak out.
Blood platelets flow into sealing site of wound.
Fever may develop slowing pathogen reproduction.
White blood cells swarm in and kill invaders.

14. Specific Immune System
Immune System – body’s defense system against disease causing organisms.
Responds to a specific pathogen through alerts triggered by antigens on the pathogen.
Recognizes them as foreign particles.
White blood cells, phagocytes, are produced for that specific invader – antibodies
Attracted to the antigens, attack them and kill them.
Creates a memory for that specific invader and develops an immunity for it.
You should not be able to get sick again from that invader.

15. Types of Immunity
Active Immunity – when your immune system makes its own antibodies in response to an antigen.
Occurs in two ways:
You either have to come down with a pathogen
Receive a vaccination for a disease
How long do they last?
Common colds with antibodies – weeks
Chicken Pox Vaccine – a lifetime
But requires boosters – an update to remind your body or the disease it’s making antibodies for.

16. Vaccines Disease Ave. Number of Cases Prior to Vaccine
Cases in 1998 – After Availability of Vaccine
Measles
503,282 89
Diphtheria
175,885 1
Tetanus
1314 34
Mumps
1,152,209
606
Rubella
47,745
345
Whooping Cough
147,271
6,279

17. Types of Immunity
Passive Immunity – Antibodies received from another source.
You are born without any memory cells in the immune system but received antibodies from your mother:
During development through the placenta
Through breast milk
How long do they last?
Only a few weeks – antibodies break down in the body.

18. Immune System Disorders
Allergic Reaction
An oversensitivity to a certain substance.
Can be a food, medicine or chemical.
Symptoms:
Itching, sneezing, runny nose, and coughing.
Autoimmune Disorder
When the immune system attacks the cells of its own body.
Rhumatoid Arthritis