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52 Cards in this Set
- Front
- Back
What is meant by hypersensitivity with respect to an immune response |
hypersensitivity is an immune response that is inappropriately triggered or excessive that produces undesirable effects on the body |
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What are the four types of hypersensitive reactions |
Type 1--IgE mediated reactions Type 2 - tissue-specific reactions Type 3 - immune complex mediated reactions Type 4 - t cell-mediated reactions |
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How do the 4 types of hypersensitivity differ with respect to their time course |
Types 1 2 3 are immediate Type 4 is delayed |
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What types of antigens are involved in development of allergic autoimmune and a low immune hypersensitivity reaction |
Allergies involve an environmental antigen Autoimmunity is a self antigen Alloimmunity is an antigen from another individual |
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Describe the sensitization process of type 1 hypersensitivity |
The first exposure to allergen leads to sensitization of mast cells During sensitization allergen-specific ige moleculesare produced and then attach to receptors on the cell membrane of mast cells or basophils subsequent exposure to allergen cause binding to ige molecules located on mast cells and basophils which caused degranulation and leads to an early response occurs within 5 to 30 minutes |
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What happens during the subsequent exposure to type 1 hypersensitivity reaction |
Subsequent exposure to allergen causes binding to ige molecule located on the mast cells basophils which causes degranulation and leads to early response. Occurs within 5 to 30 minutes Granules contain the chemical mediators of the allergy |
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What are the chemicals involved with early and late response of a type 1 hypersensitivity |
Early response Histamine, bradykinin, chemotactic factors in other chemicals Late response Leukotrienes, prostaglandins, chemotactic factors |
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Histamine |
A potent vasodilator increases permeability of capillaries bronchoconstrictor. |
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Kinins eg bradykinin |
Pro-inflammatory proteins causes vasodilation, smooth muscle contraction, leukocyte chemotaxis, and increased vascular permeability |
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Leukotrienes and prostaglandins |
These have a similar effect of histamine |
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Describes the signs and symptoms of allergic rhinitis? What are the typical allergens that trigger this condition |
Symptoms include sneezing itching and watery discharge from eyes and nose Can also produce sinusitis and bronchial asthma Severe attacks may be accompanied by systemic malaise and fatigue Headaches may be present due to sinus obstruction Typical allergens are Polynesians from ragweed, grasses, trees and weeds, fungal spores, house dust mites, animal dander and feathers. Reactions can occur year-round or appear seasonally |
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Desensitization |
Involves frequent injections of the allergen in increasing doses. high levels of IGG are produced which bind to allergen and prevent their interaction with ige molecules. |
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What are the signs and symptoms of food allergies. What are the common allergens for food allergies |
Can produce reactions in the skin gastrointestinal or respiratory tracts the most common allergens in children include milk eggs peanuts soy tree nuts fish and shellfish. In adults peanuts shellfish and fish An acute reaction would be hives systemic anaphylaxis or chronic reactions such as asthma atopic dermatitis and GI disorders |
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Describe how systemic anaphylaxis develops. what are the major signs and symptoms |
Large amounts of the chemical mediators are released from mast cells into general circulation. Systemic vasodilation leads to a sudden severe decrease in blood pressure Bronchoconstriction and edema can occur in the lungs reducing air flow decrease in oxygen within tissues can cause loss of consciousness within minutes signs and symptoms include generalized itching or tingling all over the body, difficulty in breathing followed by feelings of weakness dizziness or fainting and sense of fear and panic Hives may appear on the skin Edema may be found around eyes lips tongues hands and feet |
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What is the treatment for systemic anaphylaxis. How does it work |
Emergency treatment includes injection of epinephrine this leads to vasoconstriction in an increase in blood pressure and increases heart rate Relaxes bronchiolar smooth muscle to restore air flow |
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Vasculitis |
Inflammation of blood vessels causes changes in blood vessel walls including thickening weakening narrowing or scarring. These changes can restrict blood flow resulting in organ and tissue damage. |
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Indicate the location of antigens in a type 2 and type 3 hypersensitivity reaction |
The location of the antigens would be within the body. |
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What is meant by the ABO and Rh blood groups |
ABO. Blood groups can be O, A, B, or AB. The serum of blood group O contain IGM antibodies against both A&B carbohydrates. The serum of blood group A some of the h antigens have been modified into a antigens. The serum has antibodies against the B antigen in the serum of blood group b some of the age antigens have been modified into B antigens. The serum has antibodies against the a antigen Those with AB blood have h antigens which I've been modified into both A and B antigens. These individuals do not have antibodies to either A or B antigens The RH blood group is a group of antigens expressed only on red blood cells. It consists of at least 45 separate antigens but the most important is the d antigen. those who Express the d antigen are RH positive where's individuals who do not express the d antigen are RH negative |
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Systemic lupus erythematous sle |
It's a condition with unknown cause that can affect almost any organ system genetics play a role It is a common and serious condition Antibodies are produced against several self antigens including nucleic acids, RBCs, phospholipids ect Possible manifestations include arthritis, arthralgias, butterfly rashes on skin of nose and cheek call my hair loss, kidney damage, pleuritis, as well as others as with most autoimmune diseases is severity of manifestations will vary between flares and remission Occurs more commonly in women |
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What type of cells mediate type 4 hypersensitivity |
T cytotoxic cells or t helper cells |
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Allergic contact dermatitis |
An allergic inflammatory response confined to skin Can be caused by cosmetics hair dyes topical drugs poison ivy Signs and symptoms include blisters reading spots and elevation of skin Other signs can include a demonic resting and development of secondary infection Severity of reaction depends on allergen and person Reactions do not become a parent for 12 to 24 hours or moreremoval of irritant and application of ointments or corticosteroid creams can clear reactions More serious reactions are treated with systemic corticosteroid therapy |
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Latex allergies |
Can elicit a type 1 or type 4 response type one response is normally a reaction toward the latex proteins and can lead to anaphylaxis most common type of reaction with latex is type for response to the additives used in the manufacturing process. This leads to contact dermatitis and rashes |
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Describe how Central and peripheral tolerance is achieved within the immune system |
Central tolerance refers to deletion of t and B cells that react to self antigens during maturation of Central lymphoid organs peripheral tolerance refers to deletion or inactivation of self reactive t and B cells that escaped elimination in central lymphoid organs. Performed by the t regulatory cells |
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Describe the factors that are involved with the development of an autoimmune disease |
1 - genetics 2 - environmental factors including infectious agents 3 - molecular mimicry. Scene in rheumatic fever 4 - breakdown of tolerance |
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Why do autoimmune diseases arise |
They arise due to inappropriate reactions between the immune system and self peptides. these reactions lead to the production of antibodies against the host tissue and cells antibodies are called autoantibodies |
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How are autoimmune diseases treated |
Treatment include administering immunosuppressive therapy - methotrexate or corticosteroids Since the causes unknown the treatment is to reduce symptoms |
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Allograft |
Introduction of foreign tissue from one human into the body of another human |
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Autografts |
Tissue transferred from one part of the body to another part on the same individual |
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Xenograft |
Tissue transferred from a member of one species to a different species |
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Isograft |
Tissue transfer between two genetically identical bodies like identical twins |
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How is a successful transplant achieved |
A successful transfer of tissue or organs occurs with matching MHC (HLA) molecules between donor and recipient |
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Why is immunosuppressive therapy used on someone receiving a transplant |
Immunosuppressant drugs keep the bodies immune system from attacking the new organ |
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List three different patterns of graft rejection |
Hyperacute--occurs immediately after transplant when circulation is re-established Acute - develops after several weeks when unmatched antigens cause a reaction cronic Dodge occurs after months or years with gradual degeneration of the blood vessels. develops due to a weak immune response against minor MHC molecules on the grafted tissue |
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What is the difference between a primary and secondary immunodeficiency disorder |
A primary immunodeficiency disorder is congenital or inherited A secondary immunodeficiency disorder is acquired later in life |
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Examples of primary immunodeficiency disorders |
X-linked agammaglobulinemia which is low antibody production because of a b-cell defect DiGeorge's syndrome hypoplasia of the thymus and therefore impaired t cell immunity SCIDS severe combined immunodeficiency syndrome. A severe genetic mutation that leads to absence of all immune function. Children usually die by age 2 from opportunistic infections |
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List examples of secondary immunodeficiency disorders |
AIDS acquired immunodeficiency syndrome. Cancer. Example Hodgkin's lymphoma. Cancer of B cells leading to a reduction in normal function Immunosuppressive therapy. Corticosteroid or transplant rejection medications. |
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Indicate the common modes of transmission for HIV infection |
Transmitted person-to-person via blood semen or vaginal fluids. Through sexual intercourse or sharing of needles or from mother to fetus through the placenta. |
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Which cells are targeted by HIV |
T helper cells |
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How does HIV replicate |
it infects cells by entering a host cell and stimulating the host cell to produce new viral components in order for the virus to replicate in some cells replication occurs for years before release of new virus and other cells replication leads to cell death and release of new virus to infect other cells |
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How long does it take most individuals infected with HIV to progress to AIDS |
It can take several years |
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What are the three stages of HIV infection. What is occurring during each stage |
Primary infection. Leads to signs and symptoms of fever fatigue rash headache myalgia GI problems etc. Appears 2 to 4 weeks after exposure and last for a few days to two weeks. The immune system reduces viral numbers but does not completely eliminate them Latent period. There are no real signs or symptoms of illness as viral numbers climb this can last for several years AIDS. Persons t helper cell count has dropped to less than 200 cells per microliter. Person develops opportunistic infections in malignancies. Without medication death occurs within two to three years |
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Nociception |
Pain sense. Activation of nociceptors and the subsequent feeling of pain |
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Nociceptors |
Pain receptors. Non encapsulated free nerve endings. |
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What type of stimuli activate pain receptors |
In the unimodal nociceptors. They respond to a single stimulus mechanical or thermal. They are found primarily in the skin and mucous membranes The polymodal nociceptors respond to a variety of stimuli. Thermal chemical and mechanical |
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Which area of the body contains the majority of nociceptors |
The skin has many more nociceptors than internal structures and is therefore more sensitive to pain |
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Nociceptors adaptation |
Nociceptors do not adapt to stimulation. Adaptation means that it would become less sensitive over time |
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Neuropathic pain |
Occurs when there is damage or dysfunction in the peripheral or central nervous system |
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Types of nerve fibres a fibres |
Alpha fibres transmit motor impulses and proprioceptive information Beta fibres transmit touch and pressure sensation Gamma fibres transmit touching motor excitation of muscle spindles Delta fibres transmit pain heat cold and pressure sensations |
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What is the difference between a Delta and c fibres in terms of transmission of pain information |
A Delta fibres conduct pain impulses at a speed of 10 to 30 metres per second. Fast pain fibres. Pain conducted along these fibres usually described as sharp stabbing and localized c fibres are small and unmyelinated fibres which transmit pain and itch sensations at a speed of .5 to 2.5 metres per second. they are called slow pain fibres and comprise more than half of the sensory fibres in the peripheral nerves and all postganglionic fibres of the autonomic nervous system. Pain along these fibres are as described as diffused all an aching. |
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Describe the two function of acute pain transmitted to the central nervous system |
Acute pain information travelling to the central nervous system from the gnosis sceptre is involved with two functions Reflex motor response Alerting the brain that tissue damage is occurring or about to occur |
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Alerting the brain |
Primary order neurons enter the spinal cord via the dorsal root of a spinal nerve. Once in the dorsal Horn of the spinal cord sn1 releases neurotransmitters. Glutamate released by a Delta fibres. Glutamate and substance p release by small c fibres second-order neurons carry the pain impulses to the opposite side of the spinal cord these are interneurons |
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What is the difference between Neospinothalamic and paleospinothalamic tracts |
The Neospinothalamic tract is for fast pain The Paleospinothalamic tract is for slow pain |