Chapter 13 MED TERMS – Flashcards
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Lymphatic system has the following functions
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it reduces tissue edema by removing fluid from capillary beds. it returns the proteins from the fluids to the blood it traps and filter cellular debris such as cancer cells and microbes with the help of cells called macrophages it recycles body fluid to various parts of the body it circulates lymphocytes to assist with the immune response it moves fats from the gastrointestinal GI tract to the blood
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Immune system is the body's defense system and has the following functions
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it protects the body against foreign body invasion in normal function, it coordinates activities in the blood, body tissues and the lymphatic system to protect the body from foreign body invasion. it fights off infections and protects against future infections by producing a variety of immune responses it produces antibodies (immunoglobulins)
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lymph
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fluid that contains white blood cells and other substances and flows in the lymphatic vessels
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lymphatic pathways lymphatic vessels
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the vessels that transport lymph (the fluid of the lymphatic system) around the body. the smallest parts of these pathways are the microscopic capillaries located in the capillary beds of the body. The capillary beds are thin-walled vessels that receive fluid and debris from the bloodstream. Once inside the beds the fluid is known as lymph. The lymph travels throughout the lymphatic vessels in one direction only back toward the heart. Lymphatic vessels contain valves that prevent backflow of lymph. As the vessels approach the heart they carry more fluid and are larger in size
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lymph node
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Specialized organ that filters harmful substances from the tissues and assists in the immune response. The lymph passes through many lymph nodes for filtering so that it is ready for transferring back to the vascular system. By the time the fluid reaches the thoracic cavity, it has been filtered many times. The lymph nodes contain special cells (macrophages) that devour foreign substances. Lymph nodes become swollen with lymphocytes (lymph cells) and macrophages. Lymph nodes are located throughout the body except in the central nervous system. They are quite numerous near the joints of the body. The major groups of lymph nodes are located in the throat (the tonsils and adenoids are actually lymph tissue), neck, axilla (armpit), mediastinum, and groin.
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spleen
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Organ of lymphs system that filters and stores blood, removes old red blood cells, and activates lymphocytes. The largest lymphatic organ, it is located in the upper left portion of the abdominal cavity where unfortunately it can easily be injured and ruptured. In such cases, it must be repaired or removed (its functions are taken over by the lymph nodes, liver and bone marrow). The function of the spleen is to filter foreign material from the blood, to store blood, to remove damaged or old red blood cells and activate lymphocytes that destroy some of the foreign substances filtered from the blood. The spleen is important not only to the lymphatic system but also to the circulatory system; its association with the lymphatic system. The spleen is also a major site for immunoglobulin (antibody) production by B lymphocytes that have differentiated into antibody-producing plasma cells
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Thymus gland
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Soft gland with two lobes that is involved in immune responses located in mediastinum. It is large during infancy and early childhood when immunity is most crucial but gradually shrinks until it becomes connective tissue in adulthood (when the body has acquired other types of immunities).
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T cells (T lymphocytes
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Specialized white blood cells that receive markers in the thymus are responsible for cellular immunity and assist with humoral immunity
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B lymphocytes, B cells
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a kind of lymphocyte that manufactures antibodies
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Thymosin
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Hormone secreted by the thymus gland that aids in distribution of thymocytes (T lymphocyte) and lymphocytes
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adeno
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gland
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immuno
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immunity
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lympho
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lymph
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lymphadeno
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lymph nodes
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lymphagio
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lymphatic vessels
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spleno
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spleen
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thymo
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thymus
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toxo, toxi, toxico
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poison
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The lymphatic pathways are the vessels that transport lymph (the fluid of the lymphatic system) around the body
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Located along the lymphatic vessels are the lymph nodes, small lumps of lymphatic tissue that serve as collecting points to filter the lymph
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The largest lymphatic organ the spleen
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is located in the upper left portion of the abdominal cavity where unfortunately it can easily be injured and ruptured
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The thymus is a two-lobed soft gland located in the thoracic cavity
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The thymus gland contains a high number of T lymphocytes or T cells and a decreased number of B lymphocytes or B cells. After being produced in the bone marrow some of the thymosin a hormone secreted by the thymus
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The immune system relies on several other systems to accomplish its duties.
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The reitculoendothelial system (RES), hematopoietic system, mononuclear phagocytic system (or phagocytic system) and lymphoid system play significant roles in the functions of the immune system. The hematopoietic system is responsible for the production of the blood cells in the bone marrow. The blood cells include the erythrocytes (red blood cells), leukocytes (white blood cells), and thrombocytes (platelets). The immune system shares several parts with the lymphatic system (lymph nodes, spleen, and thymus gland). These parts serve as defense mechanisms protecting the body. Parts of other systems such as the skin and tonsils also play an important role in protecting the body from disease. The immune system of the body consists of all the processes that perform a series of defenses to protect from and respond to disease.
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The leukocytes include lymphocytes, monocytes and granulocytes (polymorphonucleated cells or PMN). The RES and phagocytic systems provide the phagocytes of the tissues and the phagocytes of the blood that are called macrophages and microphages.
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Phagocytes remove foreign particles from the body by the process of phagocytosis the internalization or "eating" of the particles and the digestion of the particles for presentation to the appropriate cells of the immune system. The immune response is divided into two kinds; the cellular response and the humoral or immunoglobulin (antibody) response
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The B cells are responsible for the production of
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antibodies (also called immunoglobulins) the humoral response
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The human body includes a number of mechanical, chemical and other defenses against disease.
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When disease causing agents, pathogens, try to enter the body they are often stopped by the skin the cilia int he nostrils and by various mucous membranes all of which are mechanical barriers to intrusion
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In the bloodstream certain substances called
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antigens may provoke an immune response to certain diseases
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Mechanical or chemical defenses work together to avert or attack disease. In addition the body has specific defenses of the immune system called immunity
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immunity that provides resistance to particular pathogens. There are three major types of immunity - natural immunity, acquired active immunity and acquired passive immunity
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natural immunity
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is the human body;s natural resistance to certain diseases
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The body develops acquired active immunity either by having a disease and producing natural antibodies to it or by being vaccinated against the disease.
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immunization or vaccination is the injection of an antigen a substance that provokes an immune response from an organism that causes active immunity via the production of antibodies. This substance is called a vaccine
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Acquired active immunity is further divided into two types. The first humoral immunity is immunity provided by plasma cells which produce antibodies called immunoglobulins
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Immunoglobulin G (IgG) is effective against bacteria, viruses and toxins Immunoglobulin A (IgA) is common in exocrine gland secretions such as breast milk, tears, nasal fluid, gastric juice and so on. IgA transfers immunity from mother to infant through breast milk Immunoglobulin M (IgM) develops in the blood plasma in response to certain antigens within the body or from foreign sources. It is the first antibody to be produced after infection Immunoglobulin D (IgD) is important in B cell activation which helps immunity by transforming itself into a plasma cell in the presence of a specific type of antigen Immunoglobulin E (IgE) appears in glandular secretions and is associated with allergic reactions
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The second type of acquired active immunity or cell-mediated immunity is provided by the action of T cells. The T cells respond to antigens by multiplying rapidly and producing proteins called lymphokines (for example interferons and interleukins) that have antiviral properties or properties that affect the actions of other cells in the body. T cells also produce substances to stimulate B cells to differentiate into plasma cells and to produce antibodies
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Three types of other specialized T cells are: helper cells or CD4 cells that stimulate the immune response cytotoxic cells or CD8 cells that help in the destruction of infected cells suppressor cells or T cells (mainly CD8 and some CD4) that suppress B cells and other immune cells
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Acquired passive immunity
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is immunity provided in the form of antibodies or antitoxins that have been developed in another person or another species. Acquired passive immunity is necessary in cases of snakebite and tetanus or any problem where immediate immunity is needed. In such cases a dose of antitoxin (antibody directed against specific toxins) is given to provide antibodies. Passive immunity may also the severity of the course of the disease. Gamma globulin is a preparation of collected antibodies given to prevent or lessen certain diseases such as hepatitis A, varicella and rabies
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Spleenectomy
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is removal of the spleen
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immunosuppressor
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an agent that suppresses the immune response
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lymphangitis
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inflammation of the lymphatic vessels
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adenocarcinoma
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glandular cancer
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lymphocyte
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is a white blood cell associated with the immune response
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toxicosis
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systemic poisoning
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lymphadenopathy
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is a disease affecting the lymph nodes
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thymectomy
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removal of the thymus
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Abnormalities of lymph organs can be checked in a CAT scan. Several blood tests that indicates the number and condition of white blood cells are used in diagnosing lymph and immune systems diseases. Human immunodeficiency virus (HIV) infection is diagnosed mainly with two blood serum tests, enzyme-linked immunosorbent and assay (ELISA or enzyme immunoassay (EIA)).
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ELISA tests blood for the antibody to the HIV virus (as well as antibodies to other specific viruses such as hepatitis B) and the Western blot is a confirming test for the presence of HIV antibodies. A diagnosis of acquired immune deficiency syndrome (AIDS) is made based on the presence of opportunistic infections and T-cells counts in specified ranges.
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Allergy tests are performed by an allergist.
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Tests usually consist of some form of exposure to a small amount of the suspected allergen to see if a reaction occurs. Now there are even home allergy tests available that can detect allergies by testing a small amount of blood.
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Cancers of the lymph system may require a lymph node dissection removal of cancerous lymph nodes for microscopic examination
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Lymphadenectomy is removal of a lymph node and a lymphadenotomy is an incision into a lymph node. A splenectomy is removal of the spleen which is usually required if it is ruptured. Other organs of the body such as the liver will take over the functions of the spleen if it is removed. a thymectomy is removal of the thymus gland which is very important to the maturation process but not as serious once a patient reaches adulthood
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Diseases of the lymphatic and immune systems are often treated with relatively high doses of chemotherapy and/or radiation. Autoimmune diseases are often managed for symptoms although some newer drugs have been able to slow the advance of such disease once thought fatal. A "cocktail" of anti-HIV drugs (such as HAART - highly active antiretroviral therapy) a potential AIDS vaccine and other newer drug compounds are bringing hope for long-term vitality to people with AIDS. Other drug compounds have been developed to fight opportunistic infections. A wide variety of antiviral drugs have been developed that are used to block virus growth and a particular anti-microorganism agent - pentamidine - is used to prevent PCP
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Allergic reactions are treated with antihistamines many of which are available over the counter. certain antihistamines are abused so that even over the counter sales may be limited .
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Allergy
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is an immune overresponse to a stimulus
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The most widespread virus that attacks the immune system is the human immunodeficiency virus (HIV)
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a virus spread by sexual contact exchange of bodily fluid or intravenous exposure. A person may be HIV positive meaning that the person carries the HIV virus but not yet come down with HIV infections (diseases that tend to occur in HIV-positive people) or has not been given a diagnosis of AIDS. Many people are HIV-positive without knowing it only a test can make that diagnosis when there are no symptoms.
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AIDS (acquired immunodeficiency syndrome) is the most widespread immunosuppressive disease that suppresses the ability of the immune system to defend against infection.
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AIDs is a complex of symptoms and caused by the HIV virus. The HIV virus is a type of retrovirus a ribonucleic acid (RNA) that causes reversal of normal cell copying. The word "retro-" (reverse) refers to its being the opposite of the ordinary method of DNA copying itself onto RNA
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AIDS patients are subject to a number of opportunistic infections, infections that a healthy immune system can easily fight off but take hold because of the lowered immune response. Many of these infections are present in other body systems.
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AIDs affects the entire body with diseases such as herpes, candidiasis, and Kaposi's sarcoma appearing on the skin and Pneumocystis carnii (proposed new name Pneumocystis jiroveci) pneumonia (PCP) appearing in the lungs. Opportunistic infections also attack the immune systems of people with immunosuppressive disorders other than AIDS. Any recipient of an organ transplant must take immunosuppressive drugs to avoid organ rejection. These drugs leave the patient open to opportunistic infections. There are a number of other immunosuppressive disorders. Some are congenital and may be inherited. Others are a result of disease for example a severe case of diabetes can weaken the immune system
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Lymphoma cancer of the lymph nodes is a relatively common cancer with high cure rates. Some AIDS patients are especially susceptible to lymphomas because of their lowered immune systems. There are many different types of lymphomas. Two of the most common are Hodgkin's lymphoma (Hodgkin's disease) a type of lymph cancer of uncertain origin that generally appears in early adulthood and non-Hodgkin's lymphoma a cancer of the lymph nodes with some cells resembling healthy cells and spreading in a diffuse pattern.
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It usually appears in mid-life. Depending on how far the disease has spread (metastasis) both types can be arrested with chemotherapy and radiation. Surgery (bone marrow transplantation) is also useful in Hodgkin's lymphoma
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Malignant tumors appear in many places in the lymph system. A thymoma is a tumor of the thymus gland. Hodgkin's lymphoma is a malignancy of the lymph nodes and spleed.
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Enlarged lymph nodes, enlarged spleen (splenomegaly) and overactive spleen (hyperslenism) characterize this disease. Non-Hodgkin's lymphoma is a disease with malignant cells that resemble large lymphocytes (lymphocytic lymphoma) or large macrophages called histiocytes (hence the name histiocytic lymphoma)
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Nonmalignant lesions on the lymph nodes, lungs, spleen, skin, and liver can indicate the presence of sarcoidosis an inflammatory condition that can affect lung function. Swollen lymph node (lymphadenopathy) can also indicated the presence of infectious mononucleosis an acute infectious disease caused by the Epstein-Barr virus. Infectious mononucleosis is often called the "kissing disease" because it is usually transmitted through mouth-to-mouth contact during kissing sharing drinks and sharing eating utensils.
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Rest is generally the only cure
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Allergies are a problem of the immune system that affect millions of people. They are due to the production of IgE antibodies against an allergen an allergy-causing substance
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Antibodies and some antigens cause a histamine to be released into the tissues and some antigens cause a histamine to be released into the tissues. This histamine release is the cause of allergy symptoms.
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Allergies vary for different people depending on time of year amount of exposure to different allergens and other immunological problems
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Hypersensitivity increases as exposure increases sometimes resulting in anaphylaxis (or anaphylactic reaction or shock) a reaction so severe that it can be life-threatening by decreasing blood pressure, affecting breathing and causing loss of consciousness. Some people are extremely allergic to peanuts. A person with a severe peanut allergy who ingests even a tiny amount of peanuts (as in a cookie) will immediately go into an anaphylactic reaction. Some people are allergic people carry a dose of epinephrine to slow the reaction
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The immune system can also turn against its own healthy tissue.
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Autoimmune disease such as rheumatoid arthritis, lupus and scleroderma results from the proliferation of T cells that react as though they were fighting a virus but are actually destroying healthy cells. Autoimmune responses often result from the body's need to fight an actual infection during which the immune system becomes overactive.
