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137 Cards in this Set
- Front
- Back
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What is the order of the first line of defense?
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- Physical defense (skin, mucous membranes)
- Chemical factors (sweat, tears) - Normal flora (bacteria that inhabit the body) |
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What is the order of the second line of defense?
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- Leukocytes (macrophages, neutrophils)
- Complement, inflammation (tissue response to infection) - Fever (body response to infection) - Fever |
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What is the order of the third line of defense?
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- B cells that produce antibodies
- T cells that regulate the immune response |
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An organism’s ability to fight off bacteria, viruses, and bacterial toxins is called ___
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immunity
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Which immunity ...
- Provides a rapid response (within seconds). - Acts against all microbes in the same way. Involves pattern recognition. - Does not have a “memory” component. |
Innate Immunity
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Which immunity ...
- Provides a slower response (requires 7-10 days to be activated). - Recognizes the antigen molecule of particular microbes. - Has a “memory” component (immunological memory). |
Adaptive Immunity
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What are the properties of neutrophils?
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- most abundant leukocyte
- usually found in blood - leaves the blood and hunts bacteria - destroys bacteria by phagocytosis - binds to bacteria - many die while destroying bacteria |
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What are the properties of an Eosinophil?
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- recognizes worms (helminths)
- dumps granules onto surface of helminth to kill them |
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What are the properties of monocytes?
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- circulate within the blood.
- become macrophages when they leave the blood and enter the tissues |
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What are the properties of macrophages?
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- 2 types (fixed and wandering)
- found in tissues - "wait" for bacteria/viruses - recruits neutrophils - are highly phagocytic. - are important for the initial detection of microbes. - can be recruited from the blood to the site of infection (after neutrophils). |
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**MICROBE TO KNOW**
Candida albicans |
- fungus
- the causative agent of yeast infections |
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What are the symptoms of inflammation?
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- pain
- heat - redness - swelling - loss of function |
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Describe acute inflammation.
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Intense, but short lived response. (cuts, boils)
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Describe chronic inflammation.
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Long lasting, more destructive response. (tuberculosis infection)
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What is involved in the first line of defense in the innate immunity?
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- intact skin
- mucous membranes and their secretions - normal micro-biota |
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What is involved in the second line of defense in the innate immunity?
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- natural killer cells and phagocytic white blood cells
- inflammation - fever - antimicrobial substance |
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What is involved in the third line of defense in the adaptive immunity?
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- specialized lymphocytes : T cells and B cells
- antibodies |
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What are the two layers of the skin?
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Epidermis and Dermis
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Describe the epidermis.
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- outermost layer
- made of tightly packed epithelial cells - contains dead cells and keratin - lacks moisture thereby preventing microbial growth |
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Describe the dermis.
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- layer or tissue beneath the epidermis
- composed of connective tissue |
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the mucous membranes produce mucus which ...
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- prevents drying out
- traps and washes microbes away |
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The ______ protects the eyes.
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lacrimal apparatus
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What is the lacrimal apparatus composed of?
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- lacrimal glands
- lacrimal canals - nasolacrimal ducts |
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what to lacrimal glands do?
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They produce tears that wash the eyes, removing microbes
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What do the lacrimal canals do?
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They drain the microbes from the eyes.
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What do the nasolacrimal ducts do?
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they drain tears into the nose.
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_____ in tears destroys Gram + microbes.
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Lysozyme
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________ dilutes and removes microbes from teeth.
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Saliva
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What is the purpose of hair?
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it traps microorganisms thereby preventing entrance into the respiratory system.
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What is the purpose of the epiglottis?
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It prevents microbes from entering the lungs.
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What is the purpose of the cilia?
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It moves microbes and dust particles out of the lower respiratory system.
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What is the purpose of urine?
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It cleanses the genitourinary system
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What is the purpose of vaginal secretions?
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It removes microbes from the female genitourinary tract.
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What is the purpose of defecation and vomiting?
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Expels microbes from the gastrointestinal tract.
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Substances made by the body that inhibit microbial growth are .....
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- sebum
- perspiration - proteins - gastric juice |
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What are the 4 proteins that are made by the body and inhibit microbial growth?
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- lysozyme
- peroxidase - iron binding proteins - defensins |
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What is sebum?
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It is an oily, acidic substance produced by skin glands that contain unsaturated fatty acids.
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what is the function of perspiration?
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It flushes and dilutes bacteria from the surface of the skin
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Where is lysozyme found?
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- tears
- saliva - sweat |
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What is the function of peroxidase?
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It generates toxic oxygen products that kill bacteria
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What are iron binding proteins?
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Steal iron from bacteria
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What are defensins?
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proteins that punch holes in bacterial cell membranes
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Describe gastric juice.
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- It contains hydrochloric acid, enzymes, and mucous.
- Destroys bacteria in the stomach |
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The normal flora (E. coli) can serve as microbial antagonists. They can:
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- Compete with pathogens for nutrients.
- Produce substance that are harmful to pathogens (bacteriocins such as colicin from E. coli). - Alter environmental conditions in certain tissues (normal flora of the vagina). |
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The innate immune system recognizes certain molecules (__________, _____________) that are found on many microbes
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- lipopolysaccharide
- peptidoglycan |
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All cells of the immune system are derived from a _________ in the bone marrow.
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hematopoietic stem cell
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Immune cells are generated through a process called __________.
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hematopoiesis
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Describe Neutrophils (PMNs).
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- are important during early stages of infection.
- recruited to an infection site by fixed macrophages. - ingest bacteria and damaged host cells. - compose 50% of circulating leukocytes. |
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Describe Basophils (and mast cells).
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- are in the blood (mast cells are in the tissues).
- protect against parasitic worms (helminths). - are involved in allergic responses. - release histamine. |
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Describe Eosinophils.
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- are mildly phagocytic.
- destroy parasitic worms (helminths). |
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______ in the bloodstream mature to ______ in the tissue.
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Monocytes; macrophages
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Describe Fixed macrophages.
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These function to detect bacteria and/or viruses and alert neutrophils.
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Describe Wandering macrophages.
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Wandering macrophages
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What are 4 examples of Fixed macrophages?
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- Kupffer’s cells (liver)
- Microglia (central nervous system) - Alveolar macrophages (lungs) - Splenic macrophages (spleen) |
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________ are stationed throughout the body and wait for an infection to occur.
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Immature dendritic cells
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Once an immature dendritic cell encounters foreign material (bacteria, viruses), it becomes a _________.
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mature dendritic cell
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________________ migrate to the nearest lymph node to activate T cells.
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mature dendritic cell
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_________________ function to kill cells of the human body that display abnormal proteins on their surfaces.
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Natural killer cells
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Natural killer cells kill virally-infected cells through a process called ______________________.
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antibody-dependent cellular cytotoxicity (ADCC)
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Macrophages and dendritic cells can recognize bacteria and viruses using _______________.
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sensor systems
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Sensor systems include:
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- Toll-like receptors (TLRs)
- NOD (nucleotide-binding oligomerization domain) proteins. |
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Toll-like receptors (TLRs) are _______________________________.
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cytoplasmic membrane proteins which recognize microbes outside of the cell
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Toll-like receptors (TLRs) recognize:
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- Lipopolysaccharides (LPS)
- Peptidoglycan - Flagellin - Bacterial nucleic acids |
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NOD (nucleotide-binding oligomerization domain) proteins recognize:
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bacteria or viruses within the cytoplasm of the cell.
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Phagocytosis is ______
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“cell eating” – ingestion of microorganisms or cell debris
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The mechanism of phagocytosis is ....
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1. Chemotaxis
- phagocytes are attracted to microbes 2. Adherance -toll-like receptors ....on phagocytes bind to lipopolysaccharide, flagellin, nucleic acids of bacteria. - opsonization...process by which bacteria are coated with serum proteins (C3b, antibodies) 3. Ingestion - pseudopods engulf the bacterium 4. Phagosome formation - pH drops (more acidic) activating hydrolytic enzymes 5. Phagolysosome formation - phagosomes fuse with lysosomes 6. Digestion - lysosomes deposit: - enzymes (lysozyme, lipases, proteases, nucleases) - toxic oxygen species (superoxide, hydrogen peroxide) 7. Residual body formation - contains remaining undigested material 8. Exocytosis - release of waste. |
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The ___________ is another sensor system designed to detect bacteria in the bloodstream or tissues.
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complement system
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_______________ are activated when they encounter bacteria in the blood or in the tissues.
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Complement proteins
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The three pathways of activation:
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- Classical pathway
- Alternative pathway - Lectin pathway. |
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Activation occurs when antibodies bind to molecules (antigens) on the surface of a bacterium. What pathway does this describe?
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Classical pathway
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Activation occurs when the complement protein C3b interacts with the surface of a bacterium. What pathway does this describe?
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Alternative pathway
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Activation occurs when mannose-binding lectins (MBLs) recognize the sugar mannose on the surface of a bacterium. What pathway does this describe?
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Lectin pathway.
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When bacteria penetrate the host tissues, __________ is triggered.
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inflammation
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What are the 3 purposes of inflammation?
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1. To destroy the infectious agent.
2. To limit the effects of the injury. 3. To repair the tissue that has been damaged by the injury. |
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Damaged tissues release chemicals that lead to inflammation:
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Histamine
Kinins Prostaglandins Leukotrienes |
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Inflammation produces:
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1. Changes in the properties of blood vessels (vasodilation and increased permeability).
2. Migration of phagocytes (neutrophils, wandering macrophages) from the bloodstream to the site of infection, ingestion of microorganisms (phagocytosis). 3. Tissue repair. |
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What results in increased blood flow and erythema (redness)?
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Blood vessels dilate (vasodilation)
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What allows fluid (complement, antibodies) and cells (neutrophils) to enter the injury site, results in edema (swelling)?
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Blood vessels become more permeable (leaky)
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_____ contains dead microbes, dead host cells, and fluid.
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Pus
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A large collection of pus is an __________.
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abscess
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Tissue is repaired by cell division in the ____ or _____.
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parenchyma/ stroma
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Functional part of the tissue (epidermis of the skin). Tissue repair forms more functional tissue. is the definition of ____________.
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Parenchyma
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Supportive framework of a tissue (dermis of the skin). Tissue repair forms scar tissue is the definition of _______.
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Stroma
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What are 3 ways that fever is helpful?
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- more immune cells are produced
- immune system chemical reactions speed up - increased body temperature may kill microbes or slow growth |
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Prolonged fever can result in ________________?
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- rapid heart rate
- dehydration - seizures - coma - death |
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When _________ is eliminated, the body experiences crisis.
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interleukin-1
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The three activation pathways activate a complement protein called_____.
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C3
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C3a and C3b then can produce three outcomes:
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- inflammation
- lysis of bacteria - opsonization of bacteria |
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When microbes are introduced into tissues, several processes are initiated:
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- The Toll-like receptors on the surfaces of fixed macrophages are activated by bacterial proteins such as lipopolysaccharide and peptidoglycan.
- Bacteria activate the complement cascade. - The damaged tissue leak chemicals that activate inflammation including - Mast cells are activated |
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_______________ are used to detect microbes in the cytoplasm of phagocytes, while _____________ is (are) used to detect microbes outside of phagocytes.
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NODs; TLRs
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Mast cells can release ______________ to activate inflammation.
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histamine
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Which of the following is a false statement?
- The first step in phagocytosis is chemotaxis. - Fever leads to increased immune cell production by the bone marrow. - The classical complement cascade involves MBLs. - The ingestion step of phagocytosis involves pseudopods. - Inflammation involves vasodilation and increased vascular permeability. |
The classical complement cascade involves MBLs.
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__________can coat microbes, leading to opsonization.
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C3b
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Which of the following lymphocytes function mainly to destroy parasitic worms?
- Eosinophils - Dendritic cells - Natural killer cells - Neutrophils Monocytes |
Eosinophils
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____________ is released by the fixed macrophage to activate the fever response.
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Interleukin-1
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_________ is found within a membrane attack complex.
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C6
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_______ can activate the inflammatory response.
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C5a
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__________ is a process used by natural killer cells to detect and destroy virally-infected host cells.
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ADCC
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_______________ deliver antigens to T cells to activate the third line of defense.
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Dendritic cells
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Adaptive immunity has the following features:
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- Displays immunological memory.
- Produces a specific response to each microbe. - Distinguishes “self” proteins from foreign proteins (tolerance to self). |
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The ________ is a group of organs designed to ensure that bacteria and viruses come into contact with B and T cells.
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lymphoid system
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A fluid called ______ circulates through the lymphoid system.
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lymph
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Macrophages and _______ (B and T cells) are present in lymph nodes.
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lymphocytes
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What are the 2 primary lymphoid organs?
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- Bone marrow
- Thymus |
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What are the 6 secondary lymphoid organs?
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- lymph nodes
- spleen - mucosal-associated lymphoid tissue (MALT) - Skin-associated lymphoid tissue (SALT) - tonsils - adenoids |
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Humoral immunity involves lymphocytes called ______ and proteins called antibodies.
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B cells
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B cells detect foreign molecules (antigens) through a protein on the surface of a B cell, called a ____________.
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B cell receptor (BCR).
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Binding to an antigen activates the B cell. The B cell matures to produce:
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- plasma cells
- memory B cells |
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_________ are molecules that interact with antibodies. Some antigens elicit a strong immune response (immunogens).
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Antigens
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What are 4 examples of antigens?
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- Bacterial capsule polysaccharides
- Sugars within peptidoglycan - Flagella proteins - Virus spike proteins |
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Antigens are made of many smaller components called ____ or antigenic determinants.
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epitopes
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Describe antibodies.
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- compact and globular in structure
- Y shaped. - Highly soluble in blood - Bind to antigens very tightly - Have multiple antigen binding sites |
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Number of binding sites is defined as ____.
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valence
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Most antibodies have 2 antigen binding sites. What 2 antibodies have more than 2 binding sites?
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- IgA
- IgM |
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Antibodies are held together by _____.
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disulfide bonds (S-S)
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Portions of the “arms” are called _____
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variable regions (V)
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The "arms" are also called ______.
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Fab (fragment antigen binding)
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Stem” and base of the “arms” is the ____________.
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constant region (C)
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“Stem” alone is called the ______.
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Fc region.
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What happens when antibodies bind to antigens?
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1. Opsonization
2. Complement activation 3. Agglutination and precipitation 4. Immobilization 5. Prevention of adherence 6. Neutralization 7. Antibody-dependent cellular cytotoxicity (ADCC) |
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The liquid portion of the blood left after the blood clots is the ____.
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serum
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The most abundant antibody in serum is ____.
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IgG (gamma globulin)
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Which antibody :
- can readily enter tissues and lymph - is a monomer - is long lived - protect against bacteria cells, toxins, and viruses - Triggers complement, enhances phagocytosis by opsonization, and neutralizes viruses - can cross the placenta - is present in colostrum |
IgG (gamma globulin)
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Which antibody :
- accounts for 5-10% of antibodies in serum - is a pentamer of 5 antibody molecules - cannot enter the tissue - involved in the initial response to antigens, particularly the bloodstream Activates complement and enhances phagocytosis by opsonization |
IgM
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Which antibody:
- Accounts for 10% of the antibodies within the serum. - Most common antibody in the body. It is abundant in the mucous membranes and body secretions. - Secretory IgA (sIgA) is a dimer of two antibody molecules. - Prevents attachment of bacteria to mucous membranes. - Neutralizes bacterial toxins and viruses. |
IgA
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Which antibody:
- Found at very low levels in the serum. - Found on the surfaces of B cells and serves as the B cell receptor. |
IgD
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Which antibody:
- Found at very low levels in the serum. - Found on the surfaces of mast cells and basophils. - Participate in the allergic responses by causing mast cells and basophils to release histamine. |
IgE
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Which of the following outcomes of antibody-antigen interaction protect the body against viruses?
- Neutralization - Prevention of adherence - Immobilization - Complement activation - Opsonization |
Neutralization
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______ is actually composed of five antibody monomers.
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IgM
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________ is the most abundant antibody in body tissues, coats the mucous membranes, and is present in body secretions
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IgA
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_________ is found in the cytoplasmic membranes of mast cells. Environmental factors that activate this antibody result in allergies.
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IgE
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A monomeric antibody molecule is composed of ______ light chain proteins and ______ heavy chain proteins.
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2;2
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Which of the following is a false statement?
- Antigens that induce an immune response are called immunogens. - Bacterial antigens can include cell wall material and flagellar proteins. - Antibodies are also called immunoglobulins. - Antibodies recognize and bind to epitopes. - Epitopes are composed of antigens |
Epitopes are composed of antigens
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The ___________ is an example of a primary lymphoid organ.
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thymus
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The “stem” portion of an antibody is also called the ________ region.
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Fc
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_______ can cross the placenta, protecting the developing fetus.
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IgG
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The __________ remove(s) antigens from the blood.
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spleen
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