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Immunology

Immunology. LINES OF DEFENSE. We live in a virtual sea of bacteria; we have evolved ways of protecting ourselves. BARRIERS : Our Goal? Keep the Beasties Out! 1. SKIN: protected by many layers of dead dry cells that are leathery. pores are protected by sweat sweat washes out pores

justin-jenkins
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Immunology

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  1. Immunology

  2. LINES OF DEFENSE • We live in a virtual sea of bacteria; we have evolved ways of protecting ourselves. • BARRIERS: Our Goal? Keep the Beasties Out! • 1. SKIN: protected by • many layers of dead dry cells that are leathery. • pores are protected by sweat • sweat washes out pores • contains lytic enzymes which burst whatever beasties that try and get in. • hair shafts protected by oils and lytic enzymes

  3. LINES OF DEFENSE • 2. EYES: Protected by • tears contain lytic enzymes and wash the eyeballs. • 3. EARS: Protected by • Wax: semi-liquid paste that traps beasties and contains lytic enzymes • Cilia: microscopic hairs that ‘wave’ rhythmically and transport the wax out of the ear. • Hairs: help to trap the beasties. • Eardrum: physical barrier keeps beasties out of middle and inner ear.

  4. LINES OF DEFENSE • 4. NOSE & RESPIRATORY SYSTEM: Protected by • Mucus: sticky and has lytic enzymes. • Cilia: transports “dirty” mucous from the lungs back to the throat where it is swallowed. • White Blood Cells: live in the air sacks (alveoli) of our lungs; they eat dirt, debris, and beasties = scavengers. • 5. MOUTH: Protected by • Saliva: contains lytic enzymes • Native Bacteria: normal bacteria that • live in your mouth will attack and destroy the new bacteria (competitive)

  5. LINES OF DEFENSE • 6. STOMACH: Protected by • Hydrochloric Acid (HCl): strong (3M) kills a lot • of bacteria & spores(?) • 7. INTESTINES: Protected by • Small Intestine: digests beasties for food • Large Intestine: is protected by native bacteria (E. coli) that fights off foreigners. • 8. REPRODUCTIVE SYSTEM: Protected by • Male system – not usually any problems. • Female system: • Barrier is at the cervix – mucous plug. • Also native bacteria, acidic environment, and WBC’s.

  6. LINES OF DEFENSE • If the bacteria gets past our physical barriers, then… • IMMUNE SYSTEM: BEASTIES IN BLOOD STREAM • 1. WHITE BLOOD CELLS (WBC’s) are phagocytic; they engulf and digest beasties. • They leave the blood go to the site of infection. • Problem: WBC’s reproduce every 3 hours and when they engulf a beasties they both die. Bacteria reproduce every 20 minutes (under optimum conditions). • Solution: Fever (increased metabolic rate) • This will slow the bacterial reproduction rate down (every 3 hours) so our WBC can keep up!

  7. White Blood Cells • Produced in our bone marrow • Our stem cells can produce several different kinds of bacteria-fighting immune cells.

  8. Phagocytosis • Leukocytes (neutrophils, eosinophils, and macrophages) engulf foreign invaders. • Complement, or complementary proteins help phagocytotic cells engulf foreign cells

  9. Phagocytosis • After phagocytosis, the cell releases a packet of enzymes that destroy the bacteria • Unfortunately the white blood cell dies too.

  10. Lymphocytes-2 kinds • Lymphocytes produce antibodies. • One kind, T cells, find antigens on bacteria, or receives messages from leukocytes, and then signal an attack.

  11. B Cells • T cells pass information along to B cells • B cells produce antibodies • Antibodies can stay on the surface of B cells, or they can be released and travel through the body to attack bacteria.

  12. Antibodies • Are “Y” shaped proteins that targe foreign invaders • Antibodies have specific genes that allow them to “match” certain bacteria and viruses • Antibodies attach and hang on to the foreign invader, and wait for a macrophage to come along and eat the whole thing.

  13. Memory • After an infection is gone, most of your white blood cells that were used, die. • Memory T cells remain though • They hold an imprint of the antigen, and can mobilize B cells super fast if they need to again • Invading pathogens are destroyed before they are even able to multiply. • This is why we rarely get the same infection twice

  14. So why do we have allergies?

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