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Ch 22 Immune System
A&P Ch 22 Immune System
Question | Answer |
---|---|
What is the function of the immune system? | Provide immunity --> protect us from infection and harmful substances |
What is the immune system function dependent on? | specific type of infectious agent |
What can infectious agents do? | Damage or kill a host |
What do pathogenic agents do? | Cause harm |
What are the 5 major categories of infectious agents? | Bacteria, viruses, fungi, protozoans, and multicellular parasites |
What are bacteria? | Single-celled prokaryotes. Most of them are harmless, some are virulent (cause serious illness) |
What are some examples of virulent (cause serious illness) bacteria? | Clostridium tetani (tetanus) and streptococcal bacteria (strep throat) |
What are viruses? | Pieces of DNA or RNA in a protein shell |
What are some examples of Viruses? | Common cold, ebola, and chickenpox |
What are fungi? | Eukaryotic cells with membrane and cell wall |
What do fungi include? | Include molds, yeasts, multicellular fungi that produce spores |
What can fungi cause? | Superficial diseases in the integument (e.g. ringworm) |
What do gunfi infect? | Infect the mucosal linings (e.g. vaginal yeast infections) |
What are Protozoans? | Eukaryotic cells without a cell wall |
What do protozoans include? | Intracellular and extracellular parasites |
What are some examples of Protozoans? | Malaria and trichomoniasis |
What is an example of a multicellular parasite? | Tapeworm? |
What are prions? | Neither cells nor viruses, but rather fragments of infectious proteins |
Where are Leukocytes formed? | In the red bone marrow |
What do granulocytes include? | Neutrophils, eosinophils, basophils |
What do monocytes become? | Macrophages |
What do lymphocytes include? | B-lymphocytes, T-lymphocytes, NK (natural killer) cells |
Where are most leukocytes found? | In body tissues (instead of blood) |
What are lymphatic tissue? | Secondary structures |
What house macrophages? | Select organs |
What houses dendritic cells? | Epithelial layers of skin and mucosal membranes |
What houses mast cells? | Connective tissue |
Where are mast cells abundant? | In dermis and mucosa of respiratory, GI, and urogenital tracts |
What are cytokines? | small proteins that regulate immune activity |
What produces Cytokines? | Cells of both innate and adaptive immune system |
What are some effects of cytokines? | Signaling cells, controlling development and behavior of immune cells, regulating inflammatory response, destroying cells |
Chemical messenger released from one cell that bind to receptors of target cells --> what is autocrine? | It can act on cell that released it |
Chemical messenger released from one cell that bind to receptors of target cells --> what is paracrine? | It acts on local cells |
Chemical messenger released from one cell that bind to receptors of target cells --> >what is endocrine? | It acts on distant cells after circulating through the blood |
What are some cytokine categories? | Interleukin (IL), Tumor necrosis factor (TNF), Colony-stimulating factor (CSF), Interferon (IFN) |
How do innate immunity and adaptive immunity differ? | Based on cells involved, specirficity of cell response, mechanisms of eliminating harmful substances, amount of time for response |
Although innate and adaptive immunities are distinct, they work together in _______. | Body defense |
What is innate immunity? | Immunity present at birth that protects against variety of different substances (non-specific), no prior exposure to substance necessary |
What does innate immunity include? | Barriers of skin and mucosal membranes, nonspecific cellular and molecular internal defenses |
How does innate immunity response? | Immediately to potentially harmful agents |
What is adaptive immunity? | Acquired immunity |
How does adaptive immunity respond? | Takes several days to be effects |
What does adaptive immunity respond to? | Response to antigen involves specific T- and B-lymphocytes; a particular cell responds to one foreign substance but not another |
What are some characteristics of innate immunity? | Prevents entry of potentially harmful substances, responds nonspecifically to a range of harmful substances, first line of defense is skin and mucosal membrane, and second line of defense involves internal processes |
What happens in the second line of defense in innate immunity? | Physiological processes such as inflammation and fever ; activities of neutrophils, macrophages, dendritic cells, eosinophils, basophils, and NK cells |
Describe the skin as a barrier | It is a physical barrier of epidermis and dermis; skin releases antimicrobial substances and has normal nonpathogenic flora (microorganisms) |
What lines the body openings? | Mucosal membranes that are lined by harmless bacteria that suppress growth of more virulent types |
What do neutrophils and macrophages destroy? | Engulfed particles |
What do dendritic cells destroy? | Particles and the present fragments |
What are present on dendritic cell surface to T-lymphocytes? | Antigens |
Basophils and mast cells promote inflammation. They release granules containing chemicals. | The chemicals increase movement of fluid from blood to injured tissue and attract immune cells (chemotactic). |
What does histamine do? | Increase vasodilation and capillary permeability |
What does heparin do? | Act as an anticoagulant |
Where does mast cells reside in? | Connective tissue, mucosa, internal organs |
What do Natural Killer (NK) cells do? | destroy a variety of unwanted cells, They form in bone marrow, circulate in blood, and accumulate in secondary lymphatic structures |
What cell performs immune surveillance (patrol the body detecting unhealthy cells)? | NK cells |
What cells do NK cells destroy? | Virus-infected cells, bacteria-infected cells, tumor cells, cells of transplanted tissue |
How do NK cells destroy unwanted cells? | They release cytotoxic chemicals |
What do eosinophils attack? | Multicellular parasites |
How do eosinophils kill parasites? | They degranulate, release enzymes and other toxic substances |
What kind of responses to eosinophils participate in? | Immune responses of allergy and asthma |
How can cells of innate immune system recognize microbes as foreign? | Because of receptors |
What are antimicrobial proteins? | Molecules that function against microbes |
What are interferons? | A class of cytokines that non-specifically impede viral spread |
What produces IFN-a and IFN-b ? | Leukocytes and virus-infected cells |
What do IFN-a and IFN-b do? | Bind to neighboring cells and prevent their infection ; stimulate NK cells to destroy virus-infected cells |
What is inflammation? | An immediate response to ward of unwanted substances. A local, nonspecific response to vascularized tissue to injury. |
What type of immunity is inflammation a part of? | Innate immunity |
Describe the initiation of inflammation. | Injured tissue, basophils, mast cells, and infectious organisms release chemicals that initiate response. The chemicals include histamine, leukotrienes, prostaglandins, and chemotactic factors |
What do released chemicals cause in the event of inflammation? | Vascular changes - vasodilation, increased capillary permeability, increased endothelial expression of molecules for leukocyte adhesion (cell-adhesion molecules, CAMS). |
What happens within 72 hours of the inflammatory response? | it slows - monocytes exit blood becoming macrophages that eat bacteria, damaged host cells, dying neutrophils; tissue repair begins as fibroblasts form new CT |
What are the cardinal signs of inflammation? | Redness, heat, swelling, pain, loss of function |
What is the duration of acute inflammation? | 8 - 10 days |
What is another name for fever? | Pyrexia |
What is fever (pyrexia)? | abnormal body temperature elevation as result from release of pyrogens from immune cells or infectious agents? |
During a fever, what does the pyrogens and hypothalamus do? | Pyrogens circulate through blood and target hypothalamus. Hypothalamus releases prostaglandin E2 and raises temp leading to fever? |
What are the fever stages? | Onset, stadium, and defervescence |
What happens in the onset stage of fever? | Temperature begins to rise - hypothalamus stimulates dermis blood vessels to constrict (less heat loss) and shivering generates heat (may be in response to chills) |
What happens in the stadium stage of fever? | Elevated temperature is maintained - metabolic rate increases to promote elimination of harmful substance; liver and spleen bind zinc and iron slowing microbial reproduction |
What happens in the defervescence stage of fever? | Temp returns to normal - hypothalamus no longer stimulated by pyrogens, prostaglandin release decrease, hypothalamus stimulates mechanisms to release heat (vasodilation, sweating) |
What are the benefits of fever? | Inhibit reproduction of bacteria and viruses, promotes interferon activity, increases activity of adaptive immunity, accelerates tissue repair, increases CAMs on endothelium of capillaries in lymph nodes, recommended to leave low fever untreated |
What are the risks to a high fever? | Changes in metabolic pathways and denaturation of protein pose risks, possible seizures, irreversible brain damage at greater than 106°F , death likely if temperature greater than 109°F |
What is considered a high fever? | 103°F in children and slightly lower in adults |
What does pus (exudate) contain? | Destroyed pathogens, dead leukocytes, macrophages, cellular debris |
How is pus removed? | By lymphatic system or through skin |
What happens if pus is not removed? | It forms an abscess |
What is an abscess? | Pus walled off with collagen fibers that requires surgical intervention to remove |
Why is ice recommended for acute inflammation? | Causes vasoconstriction of blood vessels (decreases inflammatory response), numbs the area, less painful |
What is chronic inflammation? | Inflammation continuing for longer than 2 weeks |
What is chronic inflammation characterized by? | Macrophages and lymphocytes (not neutrophils) |
What can cause chronic inflammation? | Overuse injuries, acute inflammation unable to eliminate pathogen, autoimmune disorder |
What can chronic inflammation lead to? | Tissue destruction and scar tissue formation |