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Microbiology
Chapter 15
Question | Answer |
---|---|
First line of host defense | Skin, mucous membranes, lacrimal apparatus, normal microbiota, antimicrobial peptides |
Second line of host defense | Blood cells and types, phagocytosis defense mechanisms, complement, interferons, inflammation, fever |
The Body’s First Line of Defense | skin mucous membranes |
Skin | Physical barrier to pathogens (has chemicals that defend against pathogens) *Perspiration secreted by sweat glands *Sebum secreted by sebaceous (oil) glands |
Perspiration | Salt Antimicrobial peptides – sweat glands Lysozyme |
Sebum | Lowers the pH of the skin to a level inhibitory to many bacteria |
Where can mucous membranes be found? | line all body cavities open to the outside environment *Tightly cells packed to prevent entry of pathogens *Continual shedding of cells carries attached microorganisms away (GI tract, respiratory tract, urinary tract) |
mucous | *has different variety lysozyme is present to break down peptidoglycan *Antimicrobial peptide- puncture holes in the cell membrane of pathogen enzyme shutting down cell signal inside pathogen |
mucocilary elevator | is had by cilia in respiratory tract, holds mucous. When clearing throat the mucous is either swallowed or coughed out. When coughed out the bacteria is expelled from the body;when swallowed it is killed off by the acidity of the stomach |
Lacrimal apparatus | *Produces and drains tears *Blinking spreads tears and washes surface of the eye *Lysozyme tears w/ lysozyme drain into nasal cavity that has antimicrobial peptide (host defense mechanism; on skin, mucous membranes, neutrophils, 1st line of defense) |
Role of Normal Microbiota in Innate Immunity | *helps protect the body by competing with potential pathogens *Helps stimulate the body’s second line of defense (antimicrobial peptide found in neutrophil (WBC)) |
Examples of normal microbiota | *urine has lysozyme *vomiting gets rid of organisms *pooping, coughing, sneezing, peeing |
The Body’s Second Line of Defense | *Operates when pathogens succeed in penetrating the skin or mucous membranes *Composed of cells, antimicrobial chemicals, and processes *Many of these components are found in the blood |
Defense Components of Blood | *Plasma: iron-binding compounds, complement proteins, antibodies *Erythrocytes – carry oxygen and carbon dioxide in the blood *Platelets – involved in blood clotting *Leukocytes – involved in defending the body against invaders |
Phagocytosis | non-specific host defense that uses chemotaxis to move towards infection *Cells capable of phagocytosis are called phagocytes |
Nonspecific Chemical Defenses Against Pathogens | *Complement *Interferons *Inflammation |
Complement | Set of serum proteins that once activated, results in lysis of foreign cell |
Interferons | Protein molecules released by host cells to nonspecifically inhibit the spread of viral infections |
Inflammation | Nonspecific response to tissue damage resulting from various causes Characterized by redness, heat, swelling, and pain |
Monocyte | constantly circulates in the blood stream, phagocytic, when inflammation occurs we get loosening up of venules and monocyte leaving blood cycle goes into tissue (diapedesis) |
Fever | non-specific defense against pathogen, body temp above 37 degrees Celsius. |
pyrogens | trigger the hypothalamus types: bacterial toxins (LPS, diptheria) cytoplasmic contents of bacteria released by lysis antibody-antigen cmplexes |
How do doctors use the immune response to protect you from disease? | vaccinations |
Physical barriers? | skin, mucous membrane |
What are some ways that diseases spread? -e.g.? | exchange of bodily fluid (AIDS virus, TB) |
Ingestion of contaminated food/water – e.g.? | E. coli, cholera |
Inhalation – e.g.? | Anthrax, Influenza, TB |
Vectors – e.g.? | mosquitoes (biological)/malaria fly/salmonella |
What is an example of a disease that attacks the immune system? | Rheumatoid Arthritis, lupus, HIV |
What problems can prevent the immune system from working properly? | stress, lack of sleep, etc. |
Why are immunosuppressant drugs necessary when someone has an organ transplant? | stop the body from rejecting the (host graph rejection); more susceptible to viruses |
Why is rapid detection of disease exposure important? | prevent illness or effects form worsening |
The ELISA method | *Stands for Enzyme-linked immunosorbent assay *In our lab, we used this method to detect the presence of an antigen (foreign material) |