1. And infectious diseases
Immune System
And infectious diseases

2. Immune System
The network of cells, tissues, and organs that work together to protect the body against infectious invaders.
The organs involved in the immune system are called the lymphatic system and consist of:
Thymus
Spleen
Bone Marrow
Lymph Nodes
These are important parts of the immune system because they produce or store leukocytes

3. Leukocytes
Leukocytes circulate through the blood and lymphatic system and there are two types:
Phagocytes
Lymphocytes
Cells that engulf and break down the invading organism
Most common is neutrophils, which fight bacteria
cells that allow the body to remember and recognize previous invaders and help the body destroy them
B-cells and T-cells find organisms identified by antibodies and destroys them

4. Lymphocyte Response
When foreign organisms (antigens) are recognized by the body B-cells produce antibodies
Antibodies are proteins that are developed to lock onto specific antigens
These antibodies will be present in your body for life, so the next time that antigen enters your body it is destroyed very quickly
That is how immunizations work, they introduce a weakened
antigen into your body, so your body
can produce antibodies in case a
stronger antigen returns
Antibodies cannot destroy these
antigens on their own, the T-cells
destroy the antigens

5. Types of Immunity Humans have three different types of immunity:
Innate – immunity you are born with
Adaptive – immunity that develops throughout our lives
Passive – immunity that is borrowed from another person or source

6. Innate Immunity This includes lots of our external
barriers that prevent antigens from
ever entering our bodies
Our skin prevent germs from entering our blood stream
If there is a break in the skin, it will try to heal and blood flows outward preventing the infection from getting inside
Our breathing passages are covered in hairs and mucus that are meant to trap foreign organisms and expel them from our bodies
Organisms that enter through our mouth will either be killed by the chemicals in our saliva or the acid in our stomach

7. Adaptive Immunity
Adaptive immunity includes the antibodies we develop by being exposed to different diseases throughout our lives and the vaccinations we receive

8. Passive Immunity
Sometimes we can borrow immunity from another source, but this does not usually last for very long
The most common example of this is when babies get antibodies from the mother’s breast milk, which is one reason breast feeding is beneficial for babies
Milk really does a body good (breast milk)

9. Inflammatory Response
Inflammatory response is when fluid and white blood cells leak out of the blood vessels and into the tissues.
The white blood cells fight the pathogens
During an inflammatory response, the blood vessel get wider to increase the flow of blood to that area
Because of the increase blood flow and the fluid leaking into the tissue, an inflamed area will look red and swollen. Also, the inflamed area will feel warn to the touch.
In some cases, the inflammatory response will result in you having a temperature. This high temperature keeps pathogens from reproducing.

10. Infectious Diseases
a disease that can be passed from one organism to another (called antigens or pathogens)
When you have an infectious disease, a pathogen has gotten into your body and harmed it
Pathogens make you sick by damaging individual cells
There are four major groups of pathogens

11. Bacteria Bacteria are single cell organisms
Bacteria are classified as PROKARYOTES
Most bacteria cannot make their own food; they have to break down, or decompose, other living things to obtain their energy
Most bacteria do not cause diseases
Bacteria are almost everywhere:
air, food, water, soil.
Example: Strep throat

12. Viruses
Virus – a nonliving particle consisting of a core of hereditary material surrounded by a protein coat.
Viruses can reproduce ONLY inside a living cell.
Examples: Flu, common cold

13. Fungi Most fungi are multicellular
Fungi obtain food by secreting enzymes onto the dead material outside of their bodies (external digestion). The fungi then absorb the nutrients into their cells. Organisms that feed this way are called SAPROPHYTES
Example: Athlete’s foot

14. Protists One cell organisms (unicellular) that have organelles
Example: Malaria

15. Man-Made Defenses
PASTERUIZATION – a heating process that is used today to kill microorganisms in food products such as milk
ANTIBIOTICS – a chemical that is used to kill bacteria or slow their growth without harming your body cells. Unfortunately, there is no way to cure viral diseases.

16. Spread of Disease PERSON-TO-PERSON TRANSFER CONTAMINATED OBJECTS
Diseases can be transferred by direct contact such as kissing and shaking hands
Diseases can be transferred by indirect contact such as sneezing and coughing
CONTAMINATED OBJECTS
Food and water can become contaminated
You can get ill by using contaminated objects such as towels and silverware
ANIMAL BITES
An infected animal can pass on pathogens through their bite
Examples: rabies (dog, raccoon), Lyme disease (tick), malaria (mosquitoes in tropical areas)
PATHOGENS FROM THE ENVIRONMENT
Some pathogens live naturally in the soil and water
Example: tetanus, botulism (causes food poisoning)

17. http://www. learner. org/courses/envsci/interactives/disease/disease