The Immune System

1. The Immune System Hakière Parker & Ethan Dimmock HL IB Biology January 31, 2012

2. About The Immune System • The Immune System is made up of special cells, proteins, tissues, and organs. • Through a series of steps called the immune response, the immune system attacks organisms and substances that invade body systems and cause illness and disease.

3. What Does The Immune System Consist Of? The Immune System consist of these special cells, proteins, tissues, and organs. • Blood Vessels • Bone Marrow • Lymph Nodes • Lymphatic Vessels • Spleen • Thymus • Tonsils

4. What Does Our Immune System Do? The immune system defends the human body against germs and microorganisms every day. In most cases, the immune system does a great job of keeping people healthy and preventing infections. But sometimes problems with the immune system can lead to illness and infection.

5. Defenses & Immunity • Humans have several different kinds of defenses • External Defenses • Internal Defenses • Non-specific defenses • Specific defenses • Humans have three different kinds of immunity • Innate • Adaptive • Passive

6. External Defenses Are Non-Specific • First line of defense for the body • Physical and Chemical barriers • Skin • Cannot normally be penetrated by bacteria and viruses • Secretions from sweat glands keep the skin in a pH range of 3 to 5, killing most microbes • Mucous Membranes • Line digestive, respiratory, and genitourinary tracts • Also prevents entry of harmful microbes • Traps microbes and particles in mucus • Mucus, tears, and saliva contain antimicrobial proteins such as the enzyme lysozyme

7. Non-Specific Internal Defenses • Second line of defense for the body • Functions through specialized cells and the Inflammatory Response • Natural Killer (NK) cells • Seek out virus infected or abnormal cells and burst the cell membrane (lysing) • Not phagocytic • Phagocytic Cells • Specialized cells that engulf microbes into a vacuole which fuses with a lysosome killing it • Different types • Antimicrobial proteins • A variety of proteins • Attack microbes directly

8. The Inflammatory Response • Response to tissue damage in body • Includes something like a cut, which allows entry of microorganisms into body • Blood flow increased to injured area, bringing in phagocytes to engulf the invading microbes, as well as clotting elements to begin the repair and healing process • In severe infection leukocytes release pyrogens, stimulating a fever, helping slow microbe growth, speeding tissue repair, and facilitating phagocytosis

9. Innate Immunity • Everyone is born with it • This is what allows diseases that get other organisms sick to not harm us and vice versa. • This also includes the external defenses • Such as the skin and mucous membranes

10. Adaptive Immunity • This develops throughout our lives • Adaptive immunity involves the lymphocytes and develops as people are exposed to diseases • It also develops when people are immunized against diseases through vaccination.

11. Passive Immunity • This is “given” to us by another source and only last for a short while • Responds in specific ways to particular toxins, microorganisms, aberrant body cells, and other substances marked as foreign molecules • Such as antibodies in a mothers breast milk

12. Leukocytes • A type of infection fighting white blood cell • They are vital to an effective Immune System. • They circulate through the body between the organs and nodes via lymphatic vessels and blood vessels • They are produced or stored in many locations in the body, including the thymus, spleen, and bone marrow.

13. Two Basic Types of Leukocytes • Phagocytes– Cells that destroy invading organisms. Major part of non-specific immunity. • Mainly neutrophils and macrophages • Lymphocytes – Cells that allow the body to remember and recognize previous invaders and help the body destroy them. Integral to specific immunity. • There are two kinds of lymphocytes which are B lymphocytes and T lymphocytes.

14. Neutrophil The most common type of phagocyte is the neutrophil, which primarily fights bacteria. • Usually the first to arrive • Attracted to chemical signals released by infected tissue • Self-destruct while destroying invaders • Short life span

15. Monocytes/Macrophages • Monocytes comprise about 5 percent of leukocytes • Develop into macrophages – the largest phagocytic cells • Migrate around body, going wherever needed • Destroy microbes by trapping them with long pseudopodia which attach to a microbe’s cell membrane and then engulfing and destroying them within their lysosomes • Some macrophages reside permanently in some tissues, particularly the lungs, liver, kidney, brain, and the lymphatic system

16. B Lymphocytes • Also called B Cells • Mature in Bone marrow • Consist of effector B cells (plasma cells) and memory B cells, which have receptors specific to the antigen of the foreign molecule • Plasma cells combat pathogens through the creation of antibodies • They seek out their targets and send defenses, in the form of antibodies, to lock onto them. • Antigen = anti-body generator

17. T Lymphocytes • Also called T Cells. • Mature in the Thymus • Consist of effector T cells and memory T cells • Interact with cell membrane glycoproteins encoded by the gene family called Major Histocompatibility Complex (MHC) which mark body cells as ‘self’ • Destroying the invaders that the B lymphocytes have identifiedfunction of effector T cells

18. The Process • Antigens are detected, making several types of cells work together to recognize them and respond • These cells trigger the B lymphocytes to produce antibodies. • These antibodies exist in a person's body, as to protect it from that particular antigen.

19. Antigens & Antibodies • Antigens • Viruses • Bacteria • Fungi • Antibodies • Proteins produced by B cells • Each antigen has a unique molecular shape • Used by the immune system to identify and neutralize foreign objects

20. Antibiotics • Drugs used to treat infections caused by bacteria. • Antibiotics can not be used to kill viruses however, such as HIV or Aids • There are many different types of antibiotics and they work in one of two ways. • A bactericidal antibiotic kills the bacteria. • A bactericidal either interferes with the making of the bacterium's cell wall or its cell contents. • A bacteriostatic stops bacteria from multiplying.

21. Videos • http://www.youtube.com/watch?v=IWMJIMzsEMg&feature=related • (The Immunological System – Recognition, Attack and Memory)

22. Sources Information Pictures http://medicalcenter.osu.edu/greystone/images/ei_0255.gif http://www.biocarta.com/pathfiles/h_neutrophilPathway.gif http://www.merckmanuals.com/media/home/figures/MMHE_16_183_01_eps.gif http://upload.wikimedia.org/wikipedia/commons/thumb/f/f7/B_cell_activation.png/300px-B_cell_activation.png • http://medicalcenter.osu.edu/patientcare/healthcare_services/infectious_diseases/immunesystem/pages/index.aspx • http://kidshealth.org/parent/general/body_basics/immune.html • http://www.uta.edu/biology/britton/classnotes/1442/CH43.pdf • http://www.medicalnewstoday.com/articles/10278.php • http://www.fda.gov/animalveterinary/safetyhealth/antimicrobialresistance/default.htm