3 (21) The Immune System: Innate and Adaptive Body Defenses Flashcards
What is resistance? Susceptibility?
RESISTANCE - the ability to ward off disease
SUSCEPTIBILITY - lack of resistance
What is species resistance?
certain species contract certain diseases, while others do not, usually bc they lack specific receptors that the pathogen needs to bind to in order to infect the organism
What mechanical barriers does the body possess?
skin and mucous membranes: physical barrier, keratin resistant to weak acids and bacterial enzymes and toxins, shedding of dead cells
How do cilia help? Coughing or vomiting?
- fine hairs (cilia) lining your windpipe move mucus and trapped particles away from your lungs
- coughing and sneezing remove harmful substances by flushing action
How does a lowered pH help the body? Where does this occur?
- a decrease in pH decreases and prevents growth of bacteria and fungi in the body
- sebaceous glands produce sebum (fatty acids), lactic acid on the skin, accumulation of salt, gastric juices, vaginal secretions, and lysozymes
What is lysozyme? Where is it found?
LYSOZYME => enzyme that destroy bacteria
found in tears, perspiration, saliva, and tissue fluids
How does your normal microbiota (bacteria on your skin) protect you?
inhibits the growth of pathogens by producing antibodies
How do transferrins prevent the growth of microbes?
TRANSFERRINS => proteins that tie up the free iron in the blood and interstitial fluid (they create an antimicrobial substance)
How does interferon work? Does it help the cell that made it?
INTERFERON => a glycochemical produced by the virus infected cells that cause neighboring cells to produce anti-viral proteins, enhance phagocytosis, and suppresses growth of tumor cells (does not help the cell that made it bc it is already infected)
What is complement, and in what three ways does it act?
part of the immune system that enhances (complements) the ability of antibodies and (opsonization) phagocytic cells to clear microbes and damaged cells from an organism, promote inflammation, and (cytolysis) attack the pathogen’s cell membrane
How does fever help the body fight off infection?
fever causes liver and spleen to confiscate iron and zinc needed by microbes
- increases phagocytosis
- inhibits growth of microbes
- speeds up body repair
What are the four cardinal signs of inflammation?
1 - heat 2 - swelling 3 - redness 4 - pain 5 - sometimes loss of function
What are the three stages of inflammation?
1 - vasodilation and increased permeability of blood vessels
2 - phagocyte migration (neutrophil come first, then macrophages)
3 - tissue repair
Which one accounts for most of the signs of inflammation?
stage 1 - vasodilation and increased permeability of blood vessels
What is phagocytosis?
PHAGOCYTOSIS => “cell eating” or the process by which a cell engulfs a solid particle
What are the body’s two major types of phagocytes?
neutrophils
macrophages
What is chemotaxis?
CHEMOTAXIS => the process by which neutrophils and other various WBCs migrate up the gradient of chemotactic agents to the site of injury where they devour any foreign material
What other steps are involved in phagocytosis?
1 - chemotaxis
2 - adherence
3 - ingestion
Why is adherence of the phagocyte to a bacterium sometimes difficult? What makes it easier?
- adherence can be difficult because some bacteria have external capsules that conceal their carbohydrate signatures allowing them to elude capture because phagocytes cannot bind to them
- Opsonization, coating pathogen’s with opsonins, which are complement proteins or antibodies that provide handles to which phagocyte receptors combined
What are natural killer cells? Do they have the same specificity as B cells and T cells? What do they look for on their target cells?
- Natural killer (NK) cells are a group of defensive sells (lymphocytes) that lyse or kill cancer cells and virus-infected body cells before the adaptive immune system is activated [can kill a variety of microbes, tumor cells]
- NK cells are not as specific as the B and T cells of the adaptive immune system
- NK cells look for MHC on the surface of cells; they will attack the cell if no MHC is present
What is the “magic word” when talking about immunity? What is the “magic number”?
magic word of immunity: SPECIFIC
magic number of immunity: 2