1 / 22

Immune System

Immune System. Biology March 2014 Ms. Boehm. What is the Immune System?. The body’s defense system, which fights off pathogens that cause disease- it keeps you healthy! Pathogen = a foreign substance that can cause disease Bacteria, virus, etc. 1 st Line of Defense.

sherri
Download Presentation

Immune System

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Immune System Biology March 2014 Ms. Boehm

  2. What is the Immune System? • The body’s defense system, which fights off pathogens that cause disease- it keeps you healthy! • Pathogen = a foreign substance that can cause disease Bacteria, virus, etc.

  3. 1st Line of Defense • All first line of defense is non-specific, meaning they don’t distinguish among pathogens • Skin: shields body from harmful invaders (Barrier)

  4. 1st Line of Defense • Mucus & Cilia: (Barriers) • Mucus traps foreign microbes & dust that are allowed in through nasal hair • hair-like structures (cilia) in the lungs sweep mucus upward & out of system

  5. 1st Line of Defense What’s the first thing you do when you cut your finger? • Saliva: contains chemicals that break down bacteria (Barrier)

  6. 1st Line of Defense • Stomach Acid: swallowed bacteria is broken down by strong acids in stomach (Barrier)

  7. 2nd Line of Defense • The second line of defense is non-specific as well, but is now inside the body/bloodstream • White Blood Cells: if invaders do make it inside the body, WBC’s engulf & destroy them • Also known as phagocytes or leukocytes • Perform phagocytosis- cell eating • Breakdown of bacteria occurs in lysosome Video

  8. 2nd Line of Defense • Another 2nd line of defense is the inflammatory response • The chemical response is known as histamines • you have probably taken an antihistamine before

  9. 3rd Line of Defense • The third line of defense is a specific, targeted attack on pathogens • Able to distinguish self vs. non-self invaders • Has a role in immunity Each antibody is specific to a certain antigen

  10. Types of WBC’s • Lymphocytes = originate in the bone marrow & travel throughout lymphatic system to recognize specific invaders • B cells = programmed to make certain antibodies • Develop in bone marrow • T cells = responsible for attacking & destroying harmful pathogens • Develop in thymus gland

  11. How do Antigens work? • Antigensare proteins on the outside of a pathogen, unique to each one • identifies the pathogen as non-self and the body uses it for identification and marks it for destruction • Immune system responds by releasing Antibodies, which fit onto the Antigens perfectly • Antibodies: proteins that attach to specific antigens in the body (made by WBC’s) antibody pathogen antigen

  12. What happens next? • Once the Antibodies are attached to the antigen, it triggers a macrophage to come along and engulf the entire pathogen antibody macrophage (WBC) pathogen antigen

  13. Stop and Review • What is the role of the immune system? • Compare and contrast the 1st, 2nd and 3rd lines of defense. How are they similar, how are they different? • Define antigen and antibody. Relate the two terms to each other. • What type of organelle do you think a macrophage must have a lot of?

  14. Immunity • Why is it impossible to get the same type of cold twice? • Your body has been exposed to the antigen • You make antibodies that eventually destroy it • The next time that same antigen tries to come around, those same antibodies will destroy it immediately

  15. Immunity • How do Vaccines work? • Your body is injected with dead or weakened version of the ________________.

  16. Think the flu is no big deal? • Think again… • In 1918, a particularly deadly strain of flu, called the Spanish Influenza, spread across the globe • A form of H1N1 that is present again today. • It infected 20% of the human population and killed 5%, which came out to be about 100 million people

  17. Immune Disorders • Allergies • When your immune system mistakes harmless foreign particles (dust, pollen) as serious threats • Immune system launches a response, which causes sneezing, runny nose, & watery eyes

  18. Immune Disorders • Autoimmune diseases • The immune system turns against itself • The surface proteins on our own cells are viewed as foreign and the body makes antibodies to destroy the cells • Not sure why the body turns against itself • Examples: • Rheumatoid arthritis, lupus, type I diabetes

  19. Immune Disorders • Acquired Immune Deficiency – AIDS • Caused by Human Immunodeficiency Virus (HIV) • Discovered in 1983 • Targets and kills T-cells • Immune System is weakened • HIV doesn’t kill you • Common diseases that your body can no longer fight off can become life-threatening

  20. Immune Disorders • Acquired Immune Deficiency – AIDS • Transmitted through sexual contact, blood transfusions, contaminated needles • AIDS affects over 40 million people worldwidepeople

More Related