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Ch. 6 Hematology and Immunology. Blood and the Lymphatic System. Hematology is the medical specialty that studies the anatomy and physiology of the blood and uses diagnostic tests, medical and surgical procedures, and drugs to treat blood diseases.
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Ch. 6 Hematology and Immunology Blood and the Lymphatic System
Hematology is the medical specialty that studies the anatomy and physiology of the blood and uses diagnostic tests, medical and surgical procedures, and drugs to treat blood diseases. Immunology is the medical specialty that studies the anatomy and physiology of the lymphatic system and uses diagnostic tests, medical and surgical procedures, and drugs to treat lymphatic and immune response diseases.
Two million red blood cells die every second. There are approximately 100,000 miles of blood vessels in the human body. Seven percent of a humans body weight is made up of blood. Each day 400 gallons of recycled blood are pumped through the kidneys. By donating just one pint of blood, four lives can be saved. Half your body’s red blood cells are replaced every seven days. Every two seconds, someone needs blood. There are approximately 1 billion red blood cells in two to three drops of blood. Your body usually replaces the volume of the blood you donate within 24 hours.
Anatomy and Physiology Blood -Contains blood cells, blood cell fragments, water, proteins, and clotting factors. Function: transports oxygen, carbon dioxide, nutrients, and waste products.
Lymphatic System: -Consists of the lymphatic vessels, lymph fluid, lymph nodes, lymphoid tissues, and lymphoid organs. -Forms a pathway throughout the body that is separate from that of the circulatory system. Function: Defends the body against microorganisms and cancerous cells.
Anatomy of the Blood 1. Plasma -Yellow-ish clear liquid (about 90% water) that makes up 55% of the blood. -Contains parts of the blood: erythrocytes, leukocytes, and platelets; albumin, bilirubin, hormones, complement proteins, and clotting factors; creatinine and urea.
Erythrocytes (Red Blood Cells) -Most numerous of the parts within the plasma. -Red blood cells are a round, somewhat flattened, red disk. -Do not have a nucleus. Live about 120 days. -Contains hemoglobin (iron-containing molecule) that bonds with oxygen and carbon dioxide. -Hematopoiesis, the process of forming blood cells, occurs in the red marrow of long or flat bones.
Life Cycle of an Erythrocytes: Begin as stem cells, erythroblasts, normoblasts, reticulocytes, and finally erythrocytes. When your body experiences blood loss, the kidneys secrete erythropoietin hormone that stimulates the production and maturity of erythrocytes. When blood cells die, their parts are recycled and stored in the body other uses.
Leukocytes (White Blood Cells) Granulocytes: neutrophils eosinophils basophils Agranulocytes: lymphocytes monocytes -Can be identified by the presence or absence of granules in their cytoplasm and the shape of their nucleus.
Neutrophils -Most common leukocyte, making up 40 to 60% of leukocytes in blood. Short lived: hours to days. -Nucleus has many segments or lobes, so they are also known as polymorphonucleated leukocytes (PMNs), polys, segs, or segmenters. -Develop from the red bone marrow. Function: engulf and destroy bacteria.
Eosinophils -Make up just 1 to 4% of leukocytes -Nucleus has two lobes -Develop in the red marrow Function: engulf and destroy foreign cells (pollen, animal dander, etc.); release chemicals that kill parasites
Basophils -Least common leukocyte, making up 0.5 to 1% of leukocytes. -Nucleus has more than one lobe. -Develop in the red marrow Function: release histamine at the site of tissue injury; release heparin, an anticoagulant.
Lymphocytes -Make up 20 to 40% of leukocytes. -Smallest of the white blood cells. -Nucleus is round and nearly fills the cell. -Some lymphocytes live for just a few days, while others live for many years. -Begin development in red marrow; some become B cells or natural killer cells; others migrate to the thymus to become T cells. Function: destroy viruses and produce antibodies.
Monocytes -Make up 2 to 4% of leukocytes. -Largest of the white blood cells. -Have a large amount of cytoplasm, and nucleus is large and kidney bean shaped. -Develop in the red marrow. Function: are phagocytes that engulf and destroy microorganisms, cancerous cells, dead leukocytes, and cellular debris. Are also macrophages.
Thrombocytes -Different from other blood cells because they are only cell fragments; also called Platelets. -Active in the blood-clotting process. -Begin in the red marrow as stem cells that then become megakaryoblasts, and then mature into megakaryocytes, a very large cell. -Cytoplasm of the megakaryocyte breaks away at the edges to form cell fragments (thrombocytes) that are released into the blood.
Blood Type • -Rh is positive when antigens are present on erythrocytes. • -Rh is negative when antigens are not present on erythrocytes.
Physiology of Blood Clotting 1. Platelet Aggregation- Thrombocytes form clumps to decrease blood loss. 2. Coagulation- Blood clot forms. (fibrin) 3. Hemostasis- Cessation of bleeding. After clotting factors are activated, the remaining fluid portion of plasma is called serum.
Figure 6-11 Blood clot Susumu Nishinaga/Photo Researchers, Inc.
Anatomy of the Lymphatic System Structures: Lymphatic Vessels Lymph Lymph Nodes -Similar to the blood vessels, but have a starting point and an ending point.
Beginning Point: fluid enters a lymphatic capillary and becomes lymph. End Point: ducts empty into large veins in the neck.
Characteristics: -Lymphatic capillaries have large openings in their walls that allow microorganisms and cancerous cells to enter. -Valves within the system keep the lymph flowing in one direction. -Lymph Nodes- function to filter the lymph, contain lymphocytes and macrophages that destroy microorganisms.
Physiology of the Immune Response Any microorganism that can cause disease is a pathogen. (bacteria, viruses, protozoa, fungi, yeasts) 1. Cytokines- chemicals released to injured part of body that sends white blood cells to the area. 2. Neutrophils- engulf and destroy bacteria that have been coated with antibodies. 3. Eosinophils- engulf and destroy any foreign cells, worms, eggs…ect.
4. Basophils- release histamine in response to microorganisms. 5. Monocytes- engulf and destroy pathogens that have been coated with antibodies. Also known as a macrophage. Produce: interferon, interleukin, & tumor necrosis factor. 6. Lymphocytes NK (natural killer) Cells- recognize and destroy pathogens. B Cells- from the red bone marrow; work with macrophages, produce antibodies; activate T Cells. T Cells- from the thymus gland; Helper T-Cells, Memory T-Cells, Cytotoxic T-Cells, & Suppressor T-Cells
7. Antibodies- coat pathogens to be destroyed by various types of phagocytes. Antibodies are also known as immunoglobulins. 8. Complement Proteins- nine different types; work with antibodies and drill holes into the pathogen’s cell wall.
Diseases and Conditions Blood: -Blood Dyscrasia -Hemorrhage -Pancytopenia -Septicemia
Erythrocytes: -Abnormal Red Blood Cell Morphology -Anemia Aplastic anemia Folic Acid Deficiency anemia Iron Deficiency anemia Pernicious anemia Sickle Cell anemia
Figure 6-13 Microcytic, hypochromic erythrocytes Joaquin Carillo Farga/Photo Researchers, Inc.
Figure 6-14 Sickle cell Eye of Science/Photo Researchers, Inc.
Erythrocytes: -Anisocytosis -Poikilocytosis -Polycythemia Vera -Thalassemia -Transfusion Reaction
Leukocytes: -Acquired Immunodeficiency Syndrome (AIDS) -Leukemia -Mononucleosis -Multiple Myeloma
Figure 6-16 Human immunodeficiency virus Chris Bjornberg/Photo Researchers, Inc.
Figure 6-17 Acute lymphocytic leukemia Peres/Custom Medical Stock Photo, Inc.
Thrombocytes: -Coagulopathy -Deep Venous Thrombosis (DVT) -Disseminated Intravascular Coagulation (DIC) -Hemophilia -Thrombocytopenia
Lymphatic System: -Graft-Versus-Host Disease (GVHD) -Lymphadenopathy -Lymphedema -Lymphoma Hodgkin’s Lymphoma Non-Hodgkin’s Lymphoma -Splenomegaly -Thymoma
Figure 6-19 Lymphadenopathy Custom Medical Stock Photo, Inc.
Autoimmune Disorders: -Diabetes Mellitus, Type 1 -Graves’ Disease -Hashimoto’s Thyroiditis -Inflammatory Bowel Disease -Multiple Sclerosis
Autoimmune Disorders: -Myasthenia Gravis -Psoriasis -Rheumatoid Arthritis -Scleroderma -Systemic Lupus Erythematosus
Laboratory and Diagnostic Procedures Blood Cell Tests: -Blood Type -Complete Blood Count (CBC) with Differential -Peripheral Blood Smear