Chapter 13 Goals Page 503 Students will be able to: Identify terms relating to the composition, formation, & function of blood. Differentiate among the four major blood types Identify terms related to blood clotting Build words & recognize combining forms used in blood system terminology Identify various pathologic conditions affecting blood Describe various laboratory tests & clinical procedures used with hematologic disorders, & recognize relevant abbreviations Apply your new knowledge to understanding medical terms in their proper contexts, such as medical reports & records

Blood System Chapter 13 Pages 503 – 546

Page 504 Introduction The primary function of blood is to maintain a constant environment for the other tissues. Blood: transports nutrients, gases, & wastes. transports chemical messengers called hormones from their sites of secretion in glands to distant sites where they regulate growth, reproduction, & energy production. contains proteins, white blood cells & antibodies that fight infection, & platelets (thrombocytes) & other proteins that help the blood to clot. Nutrients from food, digested in the stomach & small intestine, pass into the bloodstream through the lining cells of the small intestine. Blood then carries these nutrients to all body cells. Oxygen enters the body through the air sacs of the lungs. Red blood cells then transport the oxygen to cells throughout the body. Blood also helps remove the waste products released by cells. It carries gaseous waste (such as carbon dioxide) to the lungs to be exhaled. It carries chemical waste, such as urea, to the kidneys to be excreted in the urine.

Composition & Formation of Blood Page 504 Composition & Formation of Blood Blood is composed of: Cells = 45% of the blood – erythrocytes, leukocytes, & platelets or thrombocytes. Liquid = 55% of blood – plasma, a solution of water, proteins, sugar, salts, hormones, lipids, & vitamins.

Composition & Formation of Blood Page 504 Composition & Formation of Blood Cells All blood cells originate in the marrow cavity of bones. Both the red blood cells that carry oxygen & the white blood cells that fight infection arise from the same hematopoietic stem cells. Under the influence of proteins in the blood & bone marrow, stem cells change their size & shape to become differentiated. In this process, the cells change in size from large (immature cells) to small (mature forms), & the cells nucleolus shrinks (in red cells, the nucleus actually disappears) Hematopoietic = blood-forming Differentiated = specialized

Composition & Formation of Blood Pages 504 – 506 Composition & Formation of Blood Erythrocytes As a red blood cell matures (from erythroblast to erythrocyte), it loses its nucleus & assumes the shape of a biconcave disk. The large surface area allows for absorption & release of gases (oxygen & carbon dioxide). Red cells contain the unique protein hemoglobin, composed of heme (iron-containing pigment) & globin (protein). Hemoglobin enables the erythrocyte to carry oxygen. The combination of oxygen & hemoglobin produces the bright red color. Shape of a red blood cell = a depressed or hollow surface on each side of the cell, resembling a cough drop with a thin central portion

Composition & Formation of Blood Pages 504 – 506 Composition & Formation of Blood The hormone call erythropoietin (secreted by the kidneys) stimulates the production of erythrocytes (-poiesis means formation). They live & fulfill their role of transporting gases for about 120 days in the bloodstream. After this time, macrophages (in the spleen, liver, & bone marrow) destroy the worn-out erythrocytes. From 2 million to 10 million red cells are destroyed each second, but because they are constantly replaced, the number of circulating cells remains constant (4 million to 6 million per μL of blood).

Composition & Formation of Blood Pages 504 – 506 Composition & Formation of Blood Macrophages break down erythrocytes & hemoglobin into heme & globin (protein) portions. The heme releases iron & decomposes into a yellow-orange pigment call bilirubin. The iron in hemoglobin is used again to form new red cells or is stored in the spleen, liver, or bone marrow. Bilirubin is excreted into bile by the liver, & from bile it enters the small intestine via the common bile duct. Finally it is excreted in the stool, where its color changes to brown.

Composition & Formation of Blood Pages 506 – 507 Composition & Formation of Blood Leukocytes White blood cells are less numerous than erythrocytes, but there are five different types of mature leukocytes. 3 polymorphonuclear granulocytic leukocytes (basophil, eosinophil, & neutrophil) They end with the suffix –phil (meaning attraction to). This reflects their affinity for various dyes. 2 mononuclear leukocytes (lymphocyte & monocyte) White blood cells = 7000 to 9000 cells per μ of blood Basophils contain granules that contain heparin (an anticlotting substance) & histamine (a chemical released in allergic responses). Eosinophils contain granules that increase in allergic responses & engulf substances that trigger the allergies. Neutrophils are phagocytes (phag/o means to eat or swallow) that accumulate at sites of infection, where they ingest & destroy bacteria.

Composition & Formation of Blood Pages 506 – 507 Composition & Formation of Blood Basophils contain granules that contain heparin (an anticlotting substance) & histamine (a chemical released in allergic responses). Eosinophils contain granules that increase in allergic responses & engulf substances that trigger the allergies. Neutrophils are phagocytes (phag/o means to eat or swallow) that accumulate at sites of infection, where they ingest & destroy bacteria.

Composition & Formation of Blood Pages 506 – 507 Composition & Formation of Blood Lymphocytes play an important role in the immune response that protects the body against infection. They can directly attack foreign matter, & in addition, make antibodies that neutralize & can lead to the destruction of foreign antigens (bacteria & viruses). Monocytes are phagocytic cells that also fight disease. As macrophages, they move from the bloodstream into tissue & dispose of dead & dying cells & other tissue debris by phagocytosis.

Composition & Formation of Blood Page 508 Composition & Formation of Blood Platelets (Thrombocytes) Platelets, actually blood cell fragments, are formed in bone marrow from giant cells with multilobed nuclei called megakaryocytes. The main function of platelets is to help blood to clot.

Composition & Formation of Blood Pages 508 – 509 Composition & Formation of Blood Plasma 4 major plasma proteins are albumin, globulins, fibrinogen, & prothrombin (the last two are clotting proteins). Albumin maintains the proper proportion (& concentration) of water in the blood. Because albumin cannot pass easily through capillary walls, it remains in the blood & carries smaller molecules bound to the surface. It attracts water from the tissue back into the bloodstream & thus opposes the water’s tendency to leave the blood & leak out into tissue spaces. Edema (swelling) results when too much fluid from blood “leaks” out into tissues. This happens in a mild form when a person ingests too much salt (water is retained in the blood & seeps out into tissues) & in a severe form when a person is burned in a fire. In this situation, albumin escapes from capillaries as a result of the burn injury. Then water cannot be held in the blood; it escapes through the skin, & blood volume drops.

Composition & Formation of Blood Pages 508 – 509 Composition & Formation of Blood Globulins are another component of blood & one of the plasma proteins. There are alpha, beta, & gamma globulins. The gamma globulins are immunoglobulins, which are antibodies that bind to & sometimes destroy antigens (foreign substances). Plasmapheresis (-apheresis means removal) is the process of separating plasma from cells & then removing the plasma from the patient. In plasmapheresis, the entire blood sample is spun in a centrifuge machine, & the plasma, being lighter in weight than the cells, moves to the top of the sample. Examples of immunoglobulin antibodies are IgG (found in high concentration in plasma) & IgA (found in breast milk, saliva, tears, & respiratory mucus). Other immunoglobulins are IgM, IgD, & IgE. Immunoglobulins are separated from other plasma proteins by electrophoresis. In this process, an electrical current passes through a solution of plasma. The different proteins in plasma separate as they migrate at diferent speeds to the source of the electricity.

Page 510 Blood Types Transfusions of whole blood (cells & plasma) are used to replace blood lost after injury, during surgery, or in severe shock. A patient who is severely anemic & needs only red blood cells will receive a transfusion of packed red cells (whole blood with most of the plasma removed). Human blood falls into four main types: A, B, AB, & O. These types are based on the antigens on red blood cells & the antibodies found in each person’s serum.

Page 510 Blood Types: Cont. There are harmful effects of transfusing blood of one type into a recipient who has a different type of blood. Therefore, before blood is transfused, both the blood donor & the blood recipient are tested, to make sure that the transfused blood will be compatible with the recipient’s blood type. During transfusion, if blood is not compatible, then hemolysis (breakdown of red blood cells) occurs. This may be followed by excessive clotting in blood vessels, which is a life-threatening condition. disseminated intravascular coagulation, or DIC

Pages 510 – 511 Blood Clotting Coagulation = a complicated process involving many different substances & chemical reactions. The final result is the formation of a fibrin clot from the plasma protein fibrinogen. The suffix –gen means giving rise to. Platelets are important in beginning the process following injury to tissues or blood vessels. The platelets becomes sticky & collect, or aggregate, at the site of injury. Then, in combination with tissue & protein clotting factors, plus calcium, vitamin K, prothrombin, thrombin, fibrinogen is converted to fibrin to form a clot. Coagulation = Blood clotting usually taking less than 15 minutes

Pages 510 – 511 Blood Clotting The fibrin threads form the clot by trapping red blood cells. The clot retracts into a tight ball, leaving behind a clear fluid called serum. Normally, clots (thrombi) do not form in blood vessels unless the vessels is damaged or the flow of blood is impeded. Anticoagulant substances in the blood inhibit blood clotting, so clots do not form. In hemophilia one of the important clotting factors is missing. (usually factor IX, or factor VIII). Heparin, produced by tissue cells (especially in the liver), is an example of an anticoagulant. Other drugs such as warfarin (Coumadin) are given to patients with thromboembolic diseases to prevent the formation of clots. Newer oral anticoagulants (NOACs) work by inhibiting blood clotting factors such as thrombin.

Pages 517 – 519 Pathology Diseases of Red Blood Cells dyscrasia any abnormal or pathology condition of the blood hemochromatosis Excess iron deposits throughout the body polycythemia vera General increase in read blood cells (erythremia)

Pathology: Cont. Pages 517 – 519 anemia Deficiency in erythrocytes or hemoglobin 1) aplastic anemia Failure of blood cell production in the bone marrow 2) hemolytic anemia Reduction in red cells due to excessive destruction 3) pernicious anemia Lack of mature erythrocytes caused by inability to absorb vitamin B12 into the bloodstream 4) sickle cell anemia Hereditary disorder of abnormal hemoglobin producing sickle-shaped erythrocytes & hemolysis 5) thalassemia Inherited disorder of abnormal hemoglobin production leading to hypochromia

Page 520 Pathology: Cont. Disorders of Blood Clotting hemophilia Excessive bleeding caused by hereditary lack of factors VIII & IX necessary for blood clotting purpura Multiple pinpoint hemorrhages & accumulation of blood under the skin

Pathology: Cont. Pages 517 – 522 Diseases of White Blood Cells leukemia Increase in cancerous white blood cells (leukocytes) 1) Acute myeloid (myelocytic) leukemia (AML) 2) Acute lymphoid leukemia (ALL) 3) Chronic myeloid (myelocytic) leukemia (CML) 4) Chronic lymphoid (lymphocytic) leukemia (CLL)

Pathology: Cont. Pages 520 – 522 Diseases of White Blood Cells granulocytosis Abnormal increase in granulocytes in the blood mononucleosis Infectious disease marked by increased numbers of mononuclear leukocytes & enlarged cervical lymph nodes

Pathology: Cont. Page 522 Disease of Bone Marrow Cells multiple myeloma Malignant neoplasm of bone marrow

Laboratory Tests & Clinical Procedures Pages 522 – 523 Laboratory Tests & Clinical Procedures Laboratory Tests antiglobulin (Coombs) test Test for th presence of antibodies that coat & damage erythrocytes bleeding time Time required for blood to stop flowing from a tiny puncture wound coagulation time Time required for venous blood to clot in a test tube hematocrit (Hct) Percentage of erythrocytes in a volume of blood

Laboratory Tests & Clinical Procedures Pages 522 – 523 Laboratory Tests & Clinical Procedures Laboratory Tests complete blood count (CBC) Determination of numbers of blood cells, hemoglobin concentration, hematocrit, & red cell values - MCH, MCV, MCHC erthrocyte sedimentation rate (ESR) Speed at which erythrocytes settle out of plasma hemoglobin test (H, Hg Hgb, HGB) Total amount of hemoglobin in a sample of peripheral blood.

Laboratory Tests & Clinical Procedures Pages 522 – 523 Laboratory Tests & Clinical Procedures Laboratory Tests platelet count Number of platelets per cubic millimeter (mm3) or microliter (μL) of blood prothrombin time (PT) Test of the ability of blood to clot red blood cell count (RBC) Number of erythrocytes per cubic millimeter (mm3) or (μL) of blood red blood cell morphology Microscopic examination of a stained blood smear to determine the shape of individual red cells

Laboratory Tests & Clinical Procedures Pages 522 – 523 Laboratory Tests & Clinical Procedures Laboratory Tests white blood cell count (WBC) Number of leukocytes per cubic millimeter (mm3) or microliter (μL) of blood white blood cell differential [count] Percentage of different types of leukocytes in the blood

Laboratory Tests & Clinical Procedures Page 524 Laboratory Tests & Clinical Procedures Clinical Procedures apheresis Separation of blood into component parts & removal of a select portion from the blood blood transfusion Whole bood or cells are taken from a donor & infused into a patient bone marrow biopsy Microscopic examination of a core of bone marrow removed with a needle hematopoietic stem cell transplantation Peripheral stem cells from a compatible donor are administered to a recipient