Hematopoiesis Definition – Pluripotency, Differentiation, and Proliferation

Definition of Hematopoiesis The process through which the body generates new blood cells. In the adult, the red bone marrow and the lymph tissues (primarily the lymph nodes and the spleen) manufacture the blood cells the body needs, with extramedullary resources for erythrocyte production available as reserves from the liver, spleen (erythrocytes), and yellow bone marrow. Researchers […]

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Lymphadenopathy Definition

Definition of Lymphadenopathy Swelling and enlargement of the lymph nodes. Lymphadenopathy indicates that the affected lymph nodes are fighting an infection in nearby tissues, and the enlargement is most often benign and normal. A common manifestation of lymphadenopathy is swollen lymph nodes in the neck when a person has a sore throat, or under the […]

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Phagocytosis – Definition and Information

Definition of Phagocytosis Phagocytosis – the process through which a phagocyte (a specialized leukocyte) consumes a pathogen or other cellular particle. Phagocytosis is a key defense mechanism of the body’s immune response and may take place in the blood, primarily the domain of granulocytes (neutrophils and eosinophils), and in the tissues, primarily the realm of tissue-based monocytes (macrophages). When a pathogen […]

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Phlebotomy – Definition and Risks

Definition of Phlebotomy The clinical term for puncturing a vein with a sterile needle to withdraw blood. Phlebotomy may be diagnostic, such as when drawing blood for diagnostic blood tests, or therapeutic, such as a treatment for hemochromatosis. Phlebotomy may be mildly uncomfortable, as the needle may sting as it penetrates the skin and the […]

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Platelet Aggregation – Definition and Function

Definition of Platelet Aggregation The process through which platelets respond to chemical signals in the blood, allowing them to adhere to each other and to collagen fibers in the blood to form the hemostatic plug that will become a blood clot at the conclusion of the coagulation cascade. The formation of collagen and the conversion […]

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Splenectomy – Removal of Spleen (Surgery)

Definition of Splenectomy Splenectomy is a surgical operation to remove the spleen. Though the spleen performs many vital immune and blood-related functions, it is not essential for life. Doctors may also choose to remove the spleen for therapeutic or prophylactic (preventive) reasons in conditions such as chronic myeloid leukemia and myelofibrosis. Because the spleen contains 4 percent of the body’s blood volume […]

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The Blood and Lymph System

Blood and Lymph System Definition The blood and lymph are the cell-bearing fluids that nourish and protect the body. Physician specialists who treat conditions of the blood and lymph are hematologists. Functions of the Blood and Lymph The blood and the lymph are the body’s vital fluids, sharing responsibility for nourishment, cleansing, immune response, and […]

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Splenomegaly – Definition, Causes and Symptoms

Definition of Splenomegaly An enlarged spleen. Splenomegaly signals an underlying health condition and is not itself a disorder. The spleen is a structure of lymphatic tissue. One of its key roles is to remove old or damaged blood cells from circulation. Many circumstances and health conditions that cause increased numbers of blood cells in the […]

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Aging, Changes in The Blood and Lymph That Occur With

Blood and Lymph Changes With Advancing Age The blood undergoes a number of normal changes across the span of the lifetime. Blood cells have life spans ranging from a few hours to decades. The blood continually renews itself, producing millions of erythrocytes and thousands of leukocytes every hour. Blood cell production accelerates to meet unique health needs, such […]

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Thoracic Duct and Functions of The Lymphatic System

Definition of Thoracic Duct The largest vessel of the lymphatic system. The thoracic duct collects lymph from the cisterna chyli and the left upper body, and drains into the left subclavian vein to deliver lymph to the bloodstream. About the diameter of a pencil, the thoracic duct extends from the cisterna chyli in the central trunk to base […]

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