CE Credit Package 5A 12 Credits for $1900
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CE Credit Package 5A 12 Credits for $1900 Please submit your completed Master Answer Sheet along with payment to AST Member Services 6 W. Dry Creek Circle, Suite 200 Littleton, CO 80120 Or fax with credit card information to (303) 694-9169. Or scan and e-mail with credit card information to [email protected]. Table of Contents CE Credit Package 5A Blood Components The Challenges of Medical Futility Origins and Early Years of General Anesthesia IBD and Abdominal Surgery Role of the Surgical Technologist in Bariatric Surgery Treating Colon Cancer Surgically When Unexpected Complications Arise During Surgery Obesity: An American Epidemic bloodc componentsTERI JUNGE, CST/CFA d hole blood consists of two main elements: the formed ele- ments and the liquid element. The formed elements are cell fragments and cells, known as corpuscles, which account for approximately 45% of the total volume of the blood. The liquid element is the intracellular matrix, known as wplasma, which accounts for approximately 55% of the total volume of the blood. In the adult, hematopoiesis (blood cell production) occurs in the red bone marrow (myeloid tissue) and all types of blood cells are pro - duced from a single type of pluripotent stem cell (hemocytoblast). Addi- tionally, some leukocytes are produced by the lymphatic system. Editor’s Note: This is part of a review series of short articles about blood. An article on blood basics was published in the January 2003 issue. The attached CE covers the first two articles in this series. The Surgical Technologist 17 ATEGORY 1 Corpuscles red blood cells are replaced per second. Red The formed elements of blood are the erythro blood cells are not capable of division. cyte (red blood cell, RBC), leukocyte (white The process of erythropoiesis (red blood blood cell, WBC), and thrombocyte (platelet). cell production) is as follows: Erythrocytes • The pluripotent stem cell is stimulated by Normal mature erythrocytes are red nonnu the hormone thrombopoietin (secreted cleated biconcave disks that measure approx by the liver) to become a blood cell (red imately 7.5 microns in diameter. The bicon blood cell, white blood cell—with the cave shape increases the surface area of the exception of the lymphocyte, or a platelet) cell and allows flexibility of the cell during in the myeloid tissue (myeloid progeni passage through the capillaries. Each red tor). blood cell consists of a cell membrane, which • The myeloid progenitor is stimulated by encloses the hemoglobin and the cytoplasm. erythropoietin to produce the megakary- Hemoglobin is the red-pigmented portion ocyte/erythroid progenitor (proerythrob of the erythrocyte. Each hemoglobin mole last), which is the differentiated stem cell ccule consists of four polypeptide chains that will eventually become the erythro (known as globin) and four nonprotein pig cyte (takes approximately 12 hours) or the ments (known as heme) that contain one fer thrombocyte. rous iron atom at the center. This configura • As the euchromatic nucleus of the proery tion allows four binding sites per hemoglobin throblast begins to shrink and the cyto molecule. Hemoglobin synthesis depends on plasm darkens with ribosomes, the the presence of iron and vitamins C, B2, B3, basophilic erythroblast is formed (takes B6, B12, E, and folate (a form of a water-sol- approximately 19 hours). uble B vitamin). Hemoglobin is responsible • The basophilic erythroblast begins to pro for carrying oxygen to the cells (in the form duce hemoglobin and becomes a poly of oxyhemoglobin) and waste products (such chromatophilic erythroblast (takes as CO2 in the form of carbaminohemoglo approximately 32 hours). bin) away from the cells. Antigens (agglutino • The polychromatophilic erythroblast gens) contained within the membrane of the becomes an orthochromatic erythroblast erythrocyte determine an individual’s blood (takes approximately 48 hours). type (ABO and Rh, positive or negative). • The reticulocyte forms as the orthochro Red blood cell production is triggered by matic erythroblast shed its nucleus. an oxygen sensing (negative feedback) mech • The reticulocyte (marrow reticulocyte) anism within the cells of the kidney. A begins to mature in the bone marrow reduced number of erythrocytes results in less (takes approximately 41 hours). oxygen being delivered to the kidney (hypox • The marrow reticulocyte transitions (is ia) which in turn causes the kidney cells to extruded) into the blood (blood reticulo release an enzyme capable of converting one cyte) where it continues to mature (takes of the plasma proteins into a hormone called approximately 32 hours). erythropoietin. Erythropoietin causes the red • The circulating mature red blood cell is bone marrow to produce more red blood functional for approximately 120 days. cells. In turn, the additional red blood cells deliver more oxygen to the kidney cells and Normal destruction of aged, abnormal, or the signal to release the enzyme is disrupted. damaged red blood cells takes place primari The life span of a red blood cell is 120 days; ly in the spleen and liver but can also occur in approximately 2.5 million (1% of the total) bone marrow and lymph nodes via phagocy The Surgical Technologist 18 tosis. Hemoglobin is divided into globin and oxidants (expose the cell to destruc heme. Globin is broken down into amino tive oxygen), lysozymes (enzymes acids that are recycled. The heme is further destructive to certain bacterial cell divided into bilirubin and iron. Iron is recy membranes), or defensins (antibiotic cled to the red bone marrow and bilirubin is polypeptides that are destructive to sent to the liver and is secreted in bile. The certain bacterial cell membranes). bile is excreted into the intestine where the Neutrophils develop as follows: bilirubin is converted into pigment that is expelled with the feces. • The pluripotent stem cell is stimu lated by the hormone thrombopoi Leukocytes etin (secreted by the liver) to Leukocytes are round colorless nucleated become a blood cell (red blood cell, cells that are part of the body’s defense mech white blood cell—with the excep anism. White blood cell production is called tion of the lymphocyte, or a leukopoiesis. Leukocytes are initially released platelet) in the myeloid tissue from the bone marrow into the blood stream; (myeloid progenitor). however, they do not remain in the circulat • The myeloid progenitor is stimulat ing blood. From the blood, the various cells ed by granulocyte monocyte colony escape through the capillary walls by a stimulating factor to produce the process called diapedesis. Leukocytes are granulocyte macrophage progeni mobile cells that migrate to the extravascular tor, which is the differentiated stem tissues using amoeboid motion. Each type of cell that will eventually become leukocyte performs a different function and either a granulocyte or a monocyte. has a different life span. Leukocytes are divid • The granulocyte macrophage prog ed into two main categories: granulocytes enitor is stimulated by granulocyte and agranulocytes. colony stimulating factor to become a neutrophil. Granulocytes The cytoplasm of the granulocyte con Eosinophils tains granules. Formation of granulocytes Eosinophils account for approximate is called granulopoiesis. There are three ly 1%-3% of all leukocytes. Eosino types of granular leukocytes: neutrophils, phils use phagocytosis to ingest the eosinophils, and basophils. undesirable material and destroy it by releasing its cytotoxic granules. Func Neutrophils tion of the eosinophil is not complete Neutrophils are the most common ly understood. Eosinophils are associ type of leukocyte accounting for ated with allergic reactions, inflamma approximately 54%-62% of all leuko tion, and the destruction of parasites cytes. Mature neutrophils are released and certain types of cancer cells. from the bone marrow into the blood. Eosinophils develop from the gran The neutrophils migrate from the ulocyte macrophage progenitor (refer blood to the interstitial fluid where to neutrophil development for the ini they await activation (due to an injury tial developmental stages) when the or infection). Neutrophils use phago granulocyte macrophage progenitor cytosis to ingest other cells, bacteria, that has been stimulated by granulo necrotic tissue, and foreign particles cyte colony stimulating factor to and then destroy them with the use of become a neutrophil is additionally The Surgical Technologist 19 influenced by interleukin-5 to become neutrophil development for the initial an eosinophil. developmental stages) when the gran ulocyte macrophage progenitor is Basophils stimulated by macrophage colony Basophils account for less than 1% of stimulating factor to become a mono all leukocytes. Basophils accumulate cyte (which eventually matures to at the site of an infection or inflamma become a macrophage). tion, then release their granules that contain mediators (such as heparin, Lymphocytes histamine, and serotonin), which Lymphocytes account for approxi increase blood flow to the area. mately 25%-38% of all leukocytes. Basophils contribute to (intensify) There are two main types of lympho allergic responses such as hay fever or cytes: B-lymphocytes (cells) and T- anaphylaxis related to an insect sting. lymphocytes (cells). Lymphocytes Basophils develop from the granu mediate the immune response. locyte macrophage progenitor (refer to Lymphocytes develop as follows: neutrophil development for the initial developmental stages) when the gran