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Flashcards in Immunity Deck (27)
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1

Susceptibility

 

Immunity

 

Innate immunity

 

Adaptive immunity

Lack of resistance to a disease

 

Ability to fight off a disease

 

Defense against any pathogens

 

Resistance to a specific pathogen (immunity)

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First line of defense vs Second Line

1st line of defense (Innate)

  • Intact Skin
  • MM/secretions
  • Normal microbiota

2nd line of defense (Innate)

  • Phagocytes (neutrophil, eosinophils & Macrophages)
  • Dendritic cells
  • Inflammation
  • Fever
  • Antimicrobial substances

3rd line of defense  (Adaptive)

  • Specialized lymphocytes (T-cells & B-cells)
  • Antibodies

3


Innate Immune System

aka Nonspecific defense

from birth

 

Physical Factors - skin, mm, microbiota (prevention of entry)

Cellular Factor - phagocytes (substances in body that inhibits microbial growth)

Does not gain effectiveness with subequent infections

Responds rapidly to infection

4


How does the innate immune system recognize foreign materials such as bacteria?

Toll-like receptors (TLR) attaches to the Pathogen-associated molecular patterns (PAMP)

 

TLR induces cytokines - regulates intensity and duration of immune responses

 

 

5


Skin

Epidermis - Outer layer of skin (Tightly packed epithelial cells)

 

Upper most layer:  Dead cells contain w/ Keratin protein

Keratin Protein:  increases hydrophobicity which dries out skin and inhibits microbial growth.

 


Dermis - Inner layer of skin  (Connective tissues)

 

 

6


Mucous membrane


Consist of epithelial layer & connective tissue layer except does not have dead keratinized cells

 

Secretes fluid = mucous, glycoprotein.  Prevents tract from drying.  Produced in goblet cell of mm.

 

Mucous linnings

  • RI
  • GI
  • Genitourinary tract

7


Lacrimal apparatus


Manufactures and Drains away tears

Prevents microbes from settling on surface of eye

8


Saliva


Dilutes and washes away number of microbes

Produced in salivary gland

Contains Lysozyme, Urea, Uric acid, antibodies from adaptive immunity

9


Respiratory Tract

Mucus coated nose hairs - filters/trap inhaled air w/ dust, microoraganism & pollutant

 

Ciliated cells of lower respiratory tract - propels inhaled dust/microbes upwards toward the throat

aka ciliary escalator

 

Epiglottis - prevents infection in larynx by covering when swallowing

10


GI Tract


Expels microbes via Peristalsis, defecation and vomitting

 

Gastric Juice in stomach:  pH 1.2-3

Destroys bacterias and most toxins

11


Genitrourinary Tract


Prevents microbes from colonization by flow of urine through the urethra

 

Vaginal Secretion pH:  3.5 (inhibits microbes)

Cervical mucus has antimicrobial activity

 

Urine: Contains lysozyme, Urea, Uric acid, Hippuric acid and indicant (inhibits growth)

12

Sebum

  • Oily substance produced by sebaceous gland in skin
  • Unstaurated fatty acid in sebum - inhibit growths of certain pathogenic bacteria and fungi
  • Skin pH:  3-5 (discourages growth)
  • Perspiration flushes microbes and contains lysozymes which breaks down cell walls

13


Normal Microbiota

Normal Flora:  Humans contain 1x1013

 

  • Takes permanent residence of our body
  • Do not usually cause diseases unless opportunistic
  • i.e. Neisseria meningitidis:  normally resides in R.I. tract but can cause meningitis
  • Not innate immune system
  • Prevents overgrowth of pathogens by competiting for nutrients, producing harmful substance for pathogens and altering pH

 

Bacterial Cells:  Humans contain 1x1014

14

Second line of defense


Activated when microbes passes 1st line of defense

Encounters 1st type of cell:  Phagocytic cells

AND stimulates inflammation, fever and antimicrobial substances

15


Blood


Plasma - Fluid component

 

Formed elements - cellular component (innate & adaptive)

Leukocytes (WBC)

16


Leukocytes

 

Granulocytes vs Agranulocytes


Granulocytes - Basophil, Neutrophils, Eosinophils

 

Agranulocytes - Monocyte, Lymphocyte, Dentritic cells

17


Neutrophil


aka polymorphonuclear leukocytes (PMN)

 

highly phagocytic and motile

Activated in the 1st stage of infection

18


Basophil


Releases histamine stored in granules

 

important in inflammation and allergic responses

19


Eosinophils


Somewhat phagocytic

motile

Produces toxic proteins against multicellular parasites

 

Attaches to parasites and discharges Peroxide ions (toxin)

20


Monocytes


Turns into phagocyte when activated

Leaves bloodstream and enters tissues and matures into macrophages - removes microbes via phagocytosis

21

Dendritic cell


Abundant in epidermis, mm, thymus & lymph nodes

Are phagocytic

Initial adaptive response

22


Lymphocytes

Produces antibodies


Natural killer cells (Innate)

  • in blood, spleen, lymph nodes, red bone marrow
  • Targets infected body cells & Tumor cells by releasing perforin protein or granzymes causing cytolysis or apoptosis

 

T cells & B cells (Adaptive)

 

 

Destroys cells by cytolysis (perforin protein) and infected cells undergo apoptosis (Self destruction)

 

 

23


Diapedesis

Phagocytes squeezeing b/t endothelial cells

24


Phagocytic Cells


Fixed macrophages - does not leave tissue

  • Kupffer's cells - liver macrophages
  • Alveolar - Lung macrophages
  • Microglial Cell - Nervous system

 

Phases

  • Chemotaxis - chemical that attacts phagocytes to microorganism:  microbial product, cytokines, complement peptides, microbial products
  • Adherence - attachment of PAMP to TLR or Opsonization (mediated by antibodies or complement proteins)
  • Ingestion - extends projections (Pseudopods).  Then plasma membrane fuses to form phagosome sac where H+ ions are pumped in, reducing pH to 4.  Hydrolytic enzymen is now activated.
  • Digestion - Phagosome detaches from plasma membrane and enters cytoplasm and combines with lysosome (digestive enzyme) forming phagolysosome.

 

 

25


Inflammation


Local defensive response triggered by damaged tissue

 

Redness

Swelling (Edema)

Pain

Heat

Loss of Function

26

Histamine & Kinins

 

Prostaglandins

 

Leuktrienes

Vasodilation & Increase permeability of blood vessels

 

Intense histamine and kinnin effect

 

Increase permeability of blood vessels & phagoctyic attachment

27


Complement system

complements immune system

defensive system consisting 30+ proteins

Produced by liver

Circulates throughout body

not adaptable nor changeable

Proteins destroys by cytolysis, inflammation, phagocytosis

"C1, C2, C3...."

Inactive until split into fragments

Acts as a cascade (one triggers another until all is turned on)