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33 Cards in this Set
- Front
- Back
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Parenchymal |
The functioning cells of an organ example the hepatocytes of the liver |
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Stromal |
The supporting connective tissues of the organ-- blood vessels and nerve fibres |
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Fibrosis |
injured tissues heal by regeneration of parenchymal cells or by connective tissue repair in which scar tissue is substituted for lost parenchymal cells and stroma |
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Regeneration |
Occurs when injured cells are replaced with the same cells |
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Resolution |
Restoration of original structure and physiologic function |
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Labile cells |
Cells that continually divide and regenerate such as squamous epithelium of the skin |
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Permanent cells |
They are unable to proliferate and leave the cell cycle. An example would be neurons |
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Stable cells |
Have a low level of replication and can regenerate when signalled. For example hepatocytes of the liver |
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Connective tissue repair |
Extensive damage to both parenchymal cells and extracellular Matrix leads to repair by connective tissue instead of resolution Connective tissue repair will also occur if the parenchymal cells cannot undergo regeneration connective tissue repair allows replacement of non regenerated parenchymal cells by scar tissue. Process is called fibrosis |
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Scar tissue |
Connective tissue to replace parenchymal cells when they cannot undergo regeneration |
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Why is the intact basement membrane important for healing tissue |
Extracellular Matrix is important in acting as a scaffolding during tissue renewal. example an intact membrane is important during wound healing to allow the renewal process to occur in an organized manner |
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Explain the difference between primary and secondary intention and give examples of each |
A primary intention is a small wound for example a sutured surgical incision or a paper cut Secondary intention like Burns and large surface wounds. The tissues have undergone greater loss of tissue and contamination. Slower than primary intention with formation of larger amounts of scar tissue Infection of a wound might delay healing and change repair process from primary to secondary intention |
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Describe what happens in the three stages of healing |
The three stages of healing are inflammation, proliferation and new tissue formation, and maturation Inflammation. Begins at the time of injury and is important for preparing the wound environment for healing arterioles dilated and there is an increase in the permeability of capillaries these changes allow plasma components to leak into injured area Clotting is initiated during this time by platelets in a small surface wound to clot loses fluid and becomes hard dried scab that protects the area phagocytic cells neutrophils are first to arrive, macrophages will follow, entered the area of injured tissue remove any invading organisms debris and other foreign matter. Clean up of area is called debridement Macrophages stay for an extended period of time to secrete growth factors that stimulate epithelial cell growth, attraction of fibroblasts and angiogenesis |
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What is the role of macrophages during healing |
They enter the area of injured tissue remove any invading organisms debris and other foreign matter. This cleanup is called debridement. |
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Angiogenesis |
The growth of blood vessels from the existing vasculature |
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Role of fibroblasts in wound healing |
fibroblasts are critical and supporting New normal wound healing involved in key processes such as breaking down the fibrin clot, creating new extracellular Matrix and collagen structures to support other cells associated with effect of wound healing, as well as wound contraction |
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Granulation tissue |
New connective tissue and microscopic blood vessels that form on the surface of a wound during the healing process. Lots of fibroblasts, infiltrated inflammatory cells in a loose extracellular Matrix |
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Proliferation and new tissue formation |
Usually begins within three to four days after injury in May last as long as two weeks Fibrin clot is replaced by granulation tissue first, followed by normal tissue or scar tissue during this time period As early as three to five hours granulation tissue is formed More granulation tissue is found in tissues healing by secondary intention fibroblasts are important for production of collagen and intercellular elements that will fill in wound space scar tissue epithelial cells at the margin of the wound begin to regenerate forming a new surface layer that is similar to the destroyed ones Collagen synthesis continues in peaks within a week and continues for several weeks depending on wound size |
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Why is wound contracture important |
Wound contraction assist enclosure of wounds so that's car is smaller than original wound. It is performed by cells within granulation tissue called myofibroblast It becomes noticeable 6 to 12 days after injury aesthetically Moon contraction is beneficial however over joints this could limit movement and cause deformities |
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What is contracture of scar tissue |
Excessive contraction is called contracture of scar tissue. It can occur with burn injuries and also lead to abdominal adhesions after surgery or infection |
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Factors that affect wound healing |
Malnutrition slow the healing process and causes wounds to heal inadequate ly or incompletely Blood flow and oxygen delivery is important to supply healing tissues with nutrients and remove waste & debris Oxygen is important for collagen synthesis and digestion of microorganisms wounds in ischemic tissue become more infected more frequently than wounds in well vasculated tissue impaired inflammatory and immune response can be caused by disorders of phagocytic function, diabetes mellitus, and therapeutic administration of corticosteroid drugs |
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Define immunity what is the difference between innate and adaptive immunity |
Immunity is the ability for the body to fight off disease Innate immunity is the body's first line of defense including skin and mucous membranesas well as the second line of defense with phagocytes antimicrobial proteins natural killer cells and inflammation Adaptive immunity helps clear specific foreign matter. It takes longer to mount but is more effective in providing long-term protection |
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Describe what constitutes the first and second line of defenses |
The first line of defense is protective chemicals on the skin and mucous membranes the second line of defense includes mechanisms that help clear the body of foreign matter that have breached the first line of defense |
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What is the role of natural killer cells in immunity |
natural killer cells patrol the body and length and have the ability to kill cancer cells virus-infected cells before the third line of defense is activated they attacked our targets known specifically by identifying the lock up self cell surface receptors and recognizing cell surface carbohydrates on target cells Killing is accomplished by release of cytolytic chemicals called perforins |
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Describe how antimicrobial proteins and complement are involved with immunity |
They work by attacking microorganisms directly or inhibiting their reproduction Includes interferon and complement proteins interferon is a group of related proteins that are produced by different cells of the body--interferon Alpha, interferon beta, interferon gamma. Interferon helps protect cells from being infected by viruses they are released by viral infected cells. Interferon also activate macrophages and mobilize natural killer cells complement proteins consist of a group of plasma proteins that normally circulate in an inactive form c1, c2,...c9, factors B d & p as well as some regulatory proteins. once activated complement can directly destroy pathogens in the body as well as enhance many aspects of the inflammatory a d immune response Can be activated by three pathways classical lectin and alternative pathways |
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Describe what is meant by the following terms as it relates to adaptive immunity--specific, systemic, adaptive |
When operating effectively the immune system protect against most invading microorganisms, cancer cells and transplanted organs. Immunity is not restricted to the initial site of infection. This is systemic protection. Immune system works by recognizing one pathogen from another specificity as well as foreign substances from normal cells and proteins the system is adaptive such that it is able to produce a memory response in which it can produce a quicker and height and response when encountering a pathogen for a second or subsequent time |
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Antigen |
Substances that are foreign to the host and can induce an immune response examples include bacteria virus fungus pollen poison ivy plant resin insect venom and transplanted organs |
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Epitopes |
These are small pieces of antigens called antigenic determinants. An antigen can have several epitopes that can elicit an immune response |
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Hapten |
a small substance that usually does not elicit an immune response but can stimulate the immune system went down to larger carrier proteins. Examples include poison ivy animal dander penicillin can lead to allergies |
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Where are lymphocytes born |
Lymphocytes are produced in the bone marrow from stem cells called hemocytoblasts |
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Immunocompetence in self tolerance |
This describes the ability of the cell to tell what is image and what is foreign |
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Where do t & B lymphocytes undergo maturation |
T lymphocytes undergo maturation in the thymus B lymphocytes undergrove maturation in the bone marrow |
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Where do lymphocytes go after the maturation process |
after maturation t & B lymphocytes will circulate in the blood and lymph as well as move into the lymph nodes spleen and mucosal tissues where they await challenge by specific antigen |
