Chapter 16: Nonspecific Responses <ul><li>The immune system functions to recognize and destroy that which is foreign (non ...
Innate or nonspecific immunity <ul><li>Acts to prevent microbes from getting into the body and the elimination of those th...
1 st  line of defense – physical barriers <ul><li>Skin – the dermis and epidermis provide mechanical protection however th...
1 st  line of defense – physical barriers <ul><li>Skin cont.  </li></ul><ul><ul><li>It is home to normal microbiota which ...
The Body’s Surfaces (from a microbe’s persepctive)
1 st  line of defense – physical barriers <ul><li>Mucous membranes line the internal body cavity and act as a mechanical b...
1 st  line of defense – physical barriers <ul><li>Lacrimal apparatus manufactures and drains away tears – flushing action,...
1 st  line of defense – physical barriers <ul><li>Epiglottis – covers the larynx when swallowing and keeps microbes from e...
First-Line Defense
1st line of defense chemical factors <ul><li>Sebaceous glands of the skin produce an oily substance called sebum which for...
1st line of defense chemical factors <ul><li>Gastric juice (pH 1.2 – 3) and enzymes destroy microbes and toxins </li></ul>...
1 st  line of defense genetic components <ul><li>Species immunity – some hosts are immune to diseases of other hosts </li>...
2 nd  line of defense – formed elements in the blood <ul><li>Phagocytes  are WBCs that originate in the bone marrow, circu...
2 nd  line of defense – formed elements in the blood <ul><li>Phagocytes continued </li></ul><ul><ul><li>Neutrophils (PMNs)...
Leukocytes = White Blood Cells
The Phagocytic Process <ul><li>Chemotaxis  = phagocytes are attracted to the area of invading microbes </li></ul><ul><li>A...
The Phagocytic Process <ul><li>Digestion  =lysosomal enzymes digest the bacterium in newly formed phagolysosomes </li></ul...
Phagocytosis “ It is the toll-like receptors on macrophages that enable them to sense that the material is microbial in or...
2 nd  line of Defense - Inflammation <ul><li>Inflammation  – is a reaction to injury or infection, it is a local response ...
The Process of Inflammation <ul><li>Tissue damage  ex. Nail in skin w/ bacteria </li></ul><ul><ul><li>Mast cells are tissu...
The Process of Inflammation <ul><li>Margination  – neutrophils and monocytes  stick to endothelium of blood vessels close ...
Inflammation
Inflammation
4 Cardinal signs of inflammation <ul><li>1.  redness  (rubor) – due to increased blood flow to the area of injury – vasodi...
4 Cardinal signs of inflammation <ul><li>3.  heat  (calor)- due to increased blood flow and the action of pyrogen ( a feve...
Fever is a systemic response that accompanies inflammation <ul><li>Body temperature is set and maintained by the hypothala...
Fever is a systemic response that accompanies inflammation <ul><li>Benefits of fever: </li></ul><ul><ul><li>Inhibits multi...
2 nd  line of defense: The Complement System <ul><li>Consists of 30 different proteins circulating in the bloodstream that...
3 different complement pathways <ul><li>1. Classical pathway – rapid, efficient  </li></ul><ul><ul><li>Antibody-microbe co...
3 different complement pathways <ul><li>2.  Alternative pathway  – slower, less efficient </li></ul><ul><ul><li>Does not i...
3 different complement pathways <ul><li>3. Lectin pathway </li></ul><ul><ul><li>Macrophages stimulate the liver to release...
Results of complement activation <ul><li>Cytolysis  </li></ul><ul><ul><li>5 complement proteins bind to form a complex cal...
Results of complement activation <ul><li>Opsonization  – promotes attachment of a phagocyte to a microbe. </li></ul><ul><u...
Complement 1. Inactive complement proteins are in constant circulation. 2. Complement proteins are activated by various me...
2 nd  line of defense: Interferons <ul><li>Interferon  is a group of proteins that act to interfere with viral replication...
2 nd  line of defense: Interferons <ul><li>Interferons of a species are active against a number of different viruses – the...
Upcoming SlideShare
Loading in …5
×

Chp.16

3,001 views
2,862 views

Published on

0 Comments
1 Like
Statistics
Notes
  • Be the first to comment

No Downloads
Views
Total views
3,001
On SlideShare
0
From Embeds
0
Number of Embeds
2
Actions
Shares
0
Downloads
152
Comments
0
Likes
1
Embeds 0
No embeds

No notes for slide

Chp.16

  1. 1. Chapter 16: Nonspecific Responses <ul><li>The immune system functions to recognize and destroy that which is foreign (non self) - including invading microbes and their secretions, toxins, and enzymes and non normal cells </li></ul><ul><li>The immune system consists of 2 components: </li></ul><ul><ul><li>Nonspecific or innate (inherent) immunity </li></ul></ul><ul><ul><li>Specific or adapted (acquired after birth) immunity </li></ul></ul>
  2. 2. Innate or nonspecific immunity <ul><li>Acts to prevent microbes from getting into the body and the elimination of those that have already penetrated </li></ul><ul><li>Defenses are present at birth </li></ul><ul><li>Acts against all microbes in the same way </li></ul><ul><ul><li>Is not specific </li></ul></ul><ul><li>Always ready to respond to damage or invasion </li></ul>
  3. 3. 1 st line of defense – physical barriers <ul><li>Skin – the dermis and epidermis provide mechanical protection however this barrier can be broken by cuts and abrasions, insect bites, and injections. </li></ul><ul><ul><li>The top layer of dead epidermal cells contain a protein called keratin which is a poor source of carbon for microbes. These dead cells are continually being sloughed off along with the microbes that are on the them. </li></ul></ul>
  4. 4. 1 st line of defense – physical barriers <ul><li>Skin cont. </li></ul><ul><ul><li>It is home to normal microbiota which are antagonistic to pathogens </li></ul></ul><ul><ul><li>Flushing effects of sweat glands helps to remove microbes </li></ul></ul><ul><ul><li>A cut in the skin allows Staphylococci to enter the blood </li></ul></ul><ul><ul><li>An arthropod bite acts like a hypodermic needle – allow microbes that cause disease like malaria or plague to enter </li></ul></ul>
  5. 5. The Body’s Surfaces (from a microbe’s persepctive)
  6. 6. 1 st line of defense – physical barriers <ul><li>Mucous membranes line the internal body cavity and act as a mechanical barrier to microbes. </li></ul><ul><ul><li>Cilia in airways propel microbes and mucus into the pharynx (throat) where they are swallowed into the stomach </li></ul></ul><ul><ul><ul><li>Stomach acid destroys the microbes </li></ul></ul></ul>
  7. 7. 1 st line of defense – physical barriers <ul><li>Lacrimal apparatus manufactures and drains away tears – flushing action, blinking of eyes </li></ul><ul><li>Saliva carries microbes to the harsh environment of the stomach </li></ul><ul><li>Hairs and cilia </li></ul><ul><ul><li>Nasal hairs trap large particles, may initiate a sneeze to expel </li></ul></ul><ul><ul><li>Ciliated epithelium (respiratory tract) called the ciliary escalator moves microbes trapped in mucus out of the respiratory tract </li></ul></ul>
  8. 8. 1 st line of defense – physical barriers <ul><li>Epiglottis – covers the larynx when swallowing and keeps microbes from entering the lower respiratory tract </li></ul><ul><li>Flow of urine removes microbes from the urogenital tract </li></ul><ul><li>Vaginal secretions remove microbes from the female body </li></ul><ul><li>Defecation and vomiting expel pathogens and toxins </li></ul>
  9. 9. First-Line Defense
  10. 10. 1st line of defense chemical factors <ul><li>Sebaceous glands of the skin produce an oily substance called sebum which forms a protective film over the skin and lowers the pH of the skin to pH 3-5 </li></ul><ul><ul><li>Which inhibits the growth of pathogenic fungi and bacteria </li></ul></ul><ul><li>Sweat, tears and saliva contain the enzyme lysozyme which hydrolyzes the peptidoglycan in the cell walls of bacteria </li></ul>
  11. 11. 1st line of defense chemical factors <ul><li>Gastric juice (pH 1.2 – 3) and enzymes destroy microbes and toxins </li></ul><ul><ul><li>Except toxins of Clostridium and Staphylococcus </li></ul></ul><ul><ul><li>Helicobacter pylori – neutralizes acid and causes ulcers </li></ul></ul><ul><li>Vaginal tract has a low pH due to the normal microbiota Lactobacillus producing various acids </li></ul><ul><ul><li>Ab therapy kills off bacteria allowing Candida to overgrow causing a yeast infection </li></ul></ul>
  12. 12. 1 st line of defense genetic components <ul><li>Species immunity – some hosts are immune to diseases of other hosts </li></ul><ul><ul><li>Ex. Cats don’t get mumps and humans don’t get distemper </li></ul></ul><ul><ul><li>Not true for zoonotic pathogens that attack a broad spectrum of animals </li></ul></ul><ul><li>Differences in susceptibility in the same species ex. Gene for sickle cell anemia – resistant to malaria </li></ul>
  13. 13. 2 nd line of defense – formed elements in the blood <ul><li>Phagocytes are WBCs that originate in the bone marrow, circulate in the bloodstream for awhile, then leave the circulation, and develop in the tissues </li></ul><ul><ul><li>Macrophages are found in the spleen, bone marrow, lymph nodes, brain </li></ul></ul><ul><ul><ul><li>They develop from monocytes and monocytes are not phagocytic </li></ul></ul></ul><ul><ul><ul><li>Wandering macrophages – roam tissues and go to sites of infection or inflammation </li></ul></ul></ul><ul><ul><ul><li>Fixed macrophages enter tissues and organs and remain there </li></ul></ul></ul>
  14. 14. 2 nd line of defense – formed elements in the blood <ul><li>Phagocytes continued </li></ul><ul><ul><li>Neutrophils (PMNs) –phagocytic and motile, active in the initial stages of an infection </li></ul></ul><ul><ul><li>Eosinophils – produce toxic substances against some parasites, some phagocytosis </li></ul></ul>
  15. 15. Leukocytes = White Blood Cells
  16. 16. The Phagocytic Process <ul><li>Chemotaxis = phagocytes are attracted to the area of invading microbes </li></ul><ul><li>Adherence = phagocyte’s plasma membrane attaches to a microbe or particle surface </li></ul><ul><li>Ingestion = pseudopods surround the bacterium and bring it into the phagocyte’s cytoplasm where fusion with lysosomes take place – now called phagolysosome </li></ul>
  17. 17. The Phagocytic Process <ul><li>Digestion =lysosomal enzymes digest the bacterium in newly formed phagolysosomes </li></ul><ul><li>The process ends with the elimination of bacterial debris during egestion </li></ul>
  18. 18. Phagocytosis “ It is the toll-like receptors on macrophages that enable them to sense that the material is microbial in origin, and must therefore be eliminated quickly.” Chemotaxis = movement toward infections.
  19. 19. 2 nd line of Defense - Inflammation <ul><li>Inflammation – is a reaction to injury or infection, it is a local response </li></ul><ul><ul><li>Ex. Cat scratch, blistering of a burn, infection, allergy sxs </li></ul></ul><ul><li>Acute inflammation – short lived, responsible for a single episode or injury </li></ul><ul><li>Chronic inflammation – lasts for weeks or years, response to continuous or multiple episodes of injury </li></ul><ul><li>Inflammation is a process that limits the extent of injury </li></ul>
  20. 20. The Process of Inflammation <ul><li>Tissue damage ex. Nail in skin w/ bacteria </li></ul><ul><ul><li>Mast cells are tissue cells that trigger an inflammatory rx. By releasing histamine which is a chemical mediator that dilates blood vessels and increases vascular permeability to plasma proteins </li></ul></ul><ul><ul><li>Dilation of blood vessels increase the flow of blood at the site of irritation </li></ul></ul><ul><ul><li>Dilation BVs increases delivery of leukocytes -WBCs </li></ul></ul>
  21. 21. The Process of Inflammation <ul><li>Margination – neutrophils and monocytes stick to endothelium of blood vessels close to the injury </li></ul><ul><li>Emigration – the WBCs start getting between the endothelial cells and squeeze there way out of the vessels to reach the injured area </li></ul><ul><li>Phagocytosis – neutrophils augment phagocytosis while monocytes differentiate into macrophages . </li></ul>
  22. 22. Inflammation
  23. 23. Inflammation
  24. 24. 4 Cardinal signs of inflammation <ul><li>1. redness (rubor) – due to increased blood flow to the area of injury – vasodilation </li></ul><ul><li>2. swelling (tumor) – edema – blood leaks from vessels and you get an accumulation of fluid </li></ul><ul><ul><li>Fluid dilutes toxic substances </li></ul></ul><ul><ul><li>Fluid may contain pus which is a mixture of plasma, dead tissue cells, WBCs, dead bacteria </li></ul></ul>
  25. 25. 4 Cardinal signs of inflammation <ul><li>3. heat (calor)- due to increased blood flow and the action of pyrogen ( a fever producing substance in the blood) </li></ul><ul><li>4. pain (dolor) – caused by injury to the local nerves </li></ul><ul><li>5. the final stage if inflammation is tissue repair </li></ul>
  26. 26. Fever is a systemic response that accompanies inflammation <ul><li>Body temperature is set and maintained by the hypothalamus (brain) </li></ul><ul><li>Fever is initiated when a circulating substance called pyrogen sets the hypothalamus to a higher setting </li></ul><ul><li>Pyrogens are exogenous (coming from outside of the body) or endogenous (originating internally) </li></ul><ul><ul><li>Exogenous pyrogens are products of infectious agents </li></ul></ul><ul><ul><li>Endogenous pyrogens are liberated by monocytes, neutrophils, macrophages during phagocytosis </li></ul></ul>
  27. 27. Fever is a systemic response that accompanies inflammation <ul><li>Benefits of fever: </li></ul><ul><ul><li>Inhibits multiplication of temperature sensitive microbes </li></ul></ul><ul><ul><li>Increases metabolism and stimulates the immune response </li></ul></ul><ul><li>Complications of fever are tachycardia, dehydration, electrolyte imbalance, seizures, delirium, coma </li></ul>
  28. 28. 2 nd line of defense: The Complement System <ul><li>Consists of 30 different proteins circulating in the bloodstream that act in an ordered sequence or cascade – 1 protein activates another, etc. </li></ul><ul><ul><li>There are 9 major components C1-C9 that are sequentially activated to participate in inflammation, phagocytosis, and cytolysis </li></ul></ul>
  29. 29. 3 different complement pathways <ul><li>1. Classical pathway – rapid, efficient </li></ul><ul><ul><li>Antibody-microbe complex binds to and activates C1 which triggers the complement cascade </li></ul></ul><ul><ul><li>C3 initiates cytolysis and opsonization (coating of microbes) to promote attachment of phagocyte to microbe </li></ul></ul>
  30. 30. 3 different complement pathways <ul><li>2. Alternative pathway – slower, less efficient </li></ul><ul><ul><li>Does not involve antibodies like the classical pathway </li></ul></ul><ul><ul><li>Pathogen surface binds to C3 </li></ul></ul><ul><ul><li>Once the complement proteins combine and interact – C3 participates in inflammation, cytolysis, and opsonization </li></ul></ul>
  31. 31. 3 different complement pathways <ul><li>3. Lectin pathway </li></ul><ul><ul><li>Macrophages stimulate the liver to release lectins which enhance microbial opsonization by binding to cell CH2Os </li></ul></ul><ul><ul><li>Lectin coated pathogens bind to C4, C2 </li></ul></ul>
  32. 32. Results of complement activation <ul><li>Cytolysis </li></ul><ul><ul><li>5 complement proteins bind to form a complex called the Membrane attack complex (MAC) which embeds itself in the plasma membrane of the microbe </li></ul></ul><ul><ul><li>Channels are created in the membrane and water and salt leak into the microbe causing the cell to lyse. </li></ul></ul><ul><li>Inflammation can develop from complement proteins which combine with mast cells and trigger the release of histamine. Histamine increases blood vessel permeability. </li></ul>
  33. 33. Results of complement activation <ul><li>Opsonization – promotes attachment of a phagocyte to a microbe. </li></ul><ul><ul><li>Complement C3 coats the microbe and then reacts with receptors on the phagocytes for attachment </li></ul></ul><ul><li>Complement can be inactivated by regulatory proteins in the blood that cause the break down of activated complement </li></ul>
  34. 34. Complement 1. Inactive complement proteins are in constant circulation. 2. Complement proteins are activated by various mechanisms. 3. These are the consequences...
  35. 35. 2 nd line of defense: Interferons <ul><li>Interferon is a group of proteins that act to interfere with viral replication. </li></ul><ul><li>They are small proteins that are in 3 different types: </li></ul><ul><ul><li>Alpha and Beta INFs are produced by virus infected host cells and diffuse to neighboring uneffected cells </li></ul></ul><ul><ul><ul><li>They induce uninfected cells to manufacture mRNA for synthesis of antiviral proteins that interfere w/ viral multiplication </li></ul></ul></ul><ul><ul><ul><li>They have no effect on viral multiplication of cells already infected </li></ul></ul></ul>
  36. 36. 2 nd line of defense: Interferons <ul><li>Interferons of a species are active against a number of different viruses – they are not virus specific </li></ul><ul><li>Gamma INF is produced by lymphocytes and induce nuetrophils and macrophages to kill bacteria by phagocytosis </li></ul>

×