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Immunity part i intro_innate physical barriers
- 1. Immunity: Part I Body Defenses Against Infection
- 2. What is immunity? • The body’s defense against disease causing organisms, malfunctioning cells, and foreign particles Video
- 3. • Overview ofImmunity: • Reconnaissance, Recognition, and Response • Two major kinds of defense have evolved that counter threats: – Innate immunity – Adaptive immunity Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings
- 4. Innate Immunity •Is present before any exposure to pathogens and is effective from the time of birth • Involves nonspecific responses to pathogens • aka. Nonspecific Defenses or Innate Immunity Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings 3 m
- 5. Innate Immunity Includes: • Species resistance • Physical barriers • Phagocytic cells • Immunological surveillance • Interferons • Complement system • Inflammation • Fever Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings
- 6. Adaptive Defenses •Also called: – Specific defenses – Specific immunity – Acquired immunity • Develops only after exposure to inducing agents such as microbes, toxins, or other foreign substances (acquired) • Involves a very specific response to pathogens Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings
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- 9. External Defenses ~Skin~ - The dead, outer layer of skin, known as the epidermis, forms a shield against invaders and secretes chemicals that kill potential invaders - You shed between 40 – 50 thousand skin cells every day!
- 10. External Defenses: Hair http://www.hairdirect.com/hair/systems/s kin/hd10.aspx http://www.hmh.net/adamhealth/In- Depth%20Reports/10/000032.htm
- 11. • Secretions ofthe skin and mucous membranes – Provide an environment that is often hostile to microbes • Secretions from the skin – Give the skin a pH between 3 and 5, which is acidic enough to prevent colonization of many microbes – Also include proteins such as lysozyme, an enzyme that digests the cell walls of many bacteria Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings
- 12. Sweat • http://www.examiner.com/article/wiping-your-sweat-away-can-actually- make-your-workout-harder Tears • http://creativephotographymagazine.com/30-heart-touching-photographs- of-tears/
- 13. External Defenses ~Mucousand Cilia~ - As you breathe in, foreign particles and bacteria bump into mucus throughout your respiratory system and become stuck
- 14. External Defenses ~Mucousand Cilia~ - Hair-like structures called cilia sweep this mucus into the throat for coughing or swallowing
- 15. External Defenses ~Saliva~ - Saliva contains many chemicals that break down bacteria - Thousands of different types of bacteria can survive these chemicals, however
- 16. External Defenses ~StomachAcid~ - Swallowed bacteria are broken down by incredibly strong acids in the stomach that break down your food - The stomach must produce a coating of special mucus or this acid would eat through the stomach!
- 17. Urinary Tract •Urine flushes the urinary passageways
- 18. Reproductive Tract •Glandular secretions flush structures of the reproductive system
- 19. Think of thehuman body as a hollow plastic tube… Substances enter within the hole in the tube, but it never actually enters into the solid plastic material directly. Tube inner surface ~Digestive System~ Plastic interior ~Body~ Tube outer surface ~Skin~
- 20. Escherichia coli iscommon and plentiful in all of our digestive tracts. Why are we all not sick? - These bacteria are technically outside the body and aid in digesting material we cannot - Only if E.Coli are introduced in an unnatural manner can they break through the first line of defense and harm us
Editor's Notes
- #5 Nonspecific immunity is maintained by mechanisms that attack any irritant or abnormal substance that threatens the internal invironment. Nonspecific immunity confers general protection rather than protection from certain kinds of invading cells or substances. These defenses function the same way regardless of the invader or the number of times a particular type of organism invades.
- #9 1st line of defense for the body! External Defenses: Intact skin and mucous membranes Form physical barriers that bar the entry of microorganisms and viruses Certain cells of the mucous membranes produce mucus A viscous fluid that traps microbes and other particles
- #10 The epidermis sloughs off, removing superficial bacteria with it. Sweat is a fluid that rinses away microorganisms and foreign substances.
- #13 Mechanical washing away of substances Chemical agents within the fluid
- #14 Normal airway lining diagram 1Cilia 2Mucous gland 3Mucous layer 4Goblet cell Mucus = a viscous fluid that traps microbes and other particles
- #15 In the trachea, ciliated epithelial cells sweep mucus and any entrapped microbes upward, preventing the microbes from entering the lungs
- #16 Human saliva is composed of 99.5% water, while the other 0.5% consists of electrolytes, mucus, glycoproteins, enzymes, and antibacterial compounds such as secretory IgA and lysozyme.
- #17 Stomach = extremely hostile, even to our own cells Acidity = pH ranges from 1-2 to 4-5, depends on if and what you are eating (ex: with high protein meal, pH drops to lowest!)
- #20 As long as the barriers remain intact, many pathogens are unable to penetrate them.
- #21 Example of potential pathogen