Focus on Types of White Blood Cells

Name: Focus on Types of White Blood Cells
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Description: Focus on Types of White Blood Cells

Focus on Types of White Blood Cells
(Relates to Chapter 30, “Nursing Assessment: Hematologic System,” in the textbook) Focus on Types of White Blood Cells Copyright © 2011, 2007 by Mosby, Inc., an affiliate of Elsevier Inc.

Overview: Structures and Functions
Hematology Study of blood and blood-forming tissues Bone marrow Blood Spleen Lymph system Copyright © 2011, 2007 by Mosby, Inc., an affiliate of Elsevier Inc. 2

Hematopoiesis: Blood cell production Occurs within the bone marrow Bone marrow produces red blood cells (RBCs), white blood cells (WBCs), and platelets. Three types of cells develop from nondifferentiated immature blood cells in the bone marrow, called stem cells. Copyright © 2011, 2007 by Mosby, Inc., an affiliate of Elsevier Inc. 3

Blood Cell Development
Fig Development of blood cells. RBCs, Red blood cells; WBCs, white blood cells. Copyright © 2011, 2007 by Mosby, Inc., an affiliate of Elsevier Inc. 4

Red marrow Produces blood cells In adults, found in flat and irregular bones such as the ends of long bones, vertebrae, sacrum, sternum, ribs, flat cranial bones, and scapulae The marrow is able to respond to increased demand for various types of blood cells by increasing production via a negative-feedback system. The bone marrow is stimulated by various factors (e.g., erythropoietin) that cause differentiation of the stem cells into one of the committed hematopoietic cells (e.g., RBC). Copyright © 2011, 2007 by Mosby, Inc., an affiliate of Elsevier Inc. 6

Three functions of blood Transportation Oxygen from lungs to cells Nutrients from GI tract to cells Hormones from endocrine glands to cells Metabolic wastes from cells to lungs, liver, and kidneys Copyright © 2011, 2007 by Mosby, Inc., an affiliate of Elsevier Inc. 8

Three functions of blood Protection Combats invasion of pathogens and other foreign substances Maintains homeostasis of blood coagulation Copyright © 2011, 2007 by Mosby, Inc., an affiliate of Elsevier Inc. 10

Approx. Values for Blood Components
Two major components of blood Plasma makes up 55% of blood. Blood cells account for 45% of blood. Fig Approximate values for the components of blood in the adult. Normally, 45% of the blood is composed of blood cells, and 55% is composed of plasma. Copyright © 2011, 2007 by Mosby, Inc., an affiliate of Elsevier Inc. 11

Plasma constitutes 55% of blood. Composed primarily of water but also contains proteins, electrolytes, gases, nutrients, and waste products The term serum refers to plasma minus its clotting factors. Discuss types of plasma proteins (albumin, globulin, and clotting factors). Copyright © 2011, 2007 by Mosby, Inc., an affiliate of Elsevier Inc. 12

Primary functions of blood cells Erythrocytes (RBCs): Transportation of gases and assistance in maintaining acid-base balance Leukocytes (WBCs): Protection from infection Thrombocytes (platelets): Promote blood coagulation in response to injury Copyright © 2011, 2007 by Mosby, Inc., an affiliate of Elsevier Inc. 14

Erythrocytes (RBCs) Flexible cell wall able to alter shape to pass through small capillaries Biconcave shape and thin cell wall facilitate the diffusion of gases. Primarily composed of hemoglobin, a complex protein–iron compound that binds with oxygen and carbon dioxide As RBCs circulate through the capillaries surrounding alveoli within the lung, oxygen attaches to the iron on the hemoglobin. The oxygen-bound hemoglobin is referred to as oxyhemoglobin and is responsible for giving arterial blood its bright red appearance. As RBCs flow to body tissues, oxygen detaches from the hemoglobin and diffuses from the capillary into tissue cells. Carbon dioxide diffuses from tissue cells into the capillary, attaches to the globin portion of hemoglobin, and is transported to the lungs for removal. Discuss erythropoiesis. Copyright © 2011, 2007 by Mosby, Inc., an affiliate of Elsevier Inc. 15

Leukocytes (WBCs) Appear white when separated from blood Originate from stem cells within bone marrow Two categories of leukocytes are granulocytes (three types) and agranulocytes (two types). Five different types of leukocytes, each with a different function Granulocytes include three types: neutrophils, basophils, and eosinophils. Agranulocytes include lymphocytes and monocytes. Copyright © 2011, 2007 by Mosby, Inc., an affiliate of Elsevier Inc. 16

Types and Functions of Leukocytes
CELL FUNCTION Granulocytes Neutrophil Phagocytosis, early phase of inflammation Eosinophil Phagocytosis, parasitic infection Basophil Inflammatory response, allergic response Agranulocytes Lymphocyte Cellular, humoral immune response Monocyte Phagocytosis, cellular immune response Copyright © 2011, 2007 by Mosby, Inc., an affiliate of Elsevier Inc. 17

Copyright © 2011, 2007 by Mosby, Inc., an affiliate of Elsevier Inc.
Leukocytes Granulocytes: Contain granules within the cytoplasm Neutrophils: Most common form, with 50% to 70% of all leukocytes being neutrophils Eosinophils: Only 2% to 4% of all leukocytes Basophils: Less than 2% of all leukocytes Copyright © 2011, 2007 by Mosby, Inc., an affiliate of Elsevier Inc. 18

Leukocytes Agranulocytes: Do not contain granules within the cytoplasm and are also called mononuclear cells because they have one discrete nucleus Lymphocytes: Make up 20% to 40% of leukocytes Monocytes: Account for approximately 4% to 8% of all leukocytes Copyright © 2011, 2007 by Mosby, Inc., an affiliate of Elsevier Inc. 19

Leukocytes Granulocytes Neutrophils Primary function is phagocytosis. Primary phagocytic cells involved in acute inflammatory response Mature neutrophil is segmented (“seg”), with multiple segments in its nucleus. Copyright © 2011, 2007 by Mosby, Inc., an affiliate of Elsevier Inc. 20

Leukocytes Granulocytes Neutrophils (cont'd) Immature neutrophils are called bands (for the nonsegmented appearance of the nucleus). Mature neutrophils are more efficient phagocytes than bands. Copyright © 2011, 2007 by Mosby, Inc., an affiliate of Elsevier Inc. 21

Leukocytes Granulocytes Neutrophils (cont'd) First at site of infection An increase in percent of bands is called a shift to the left, meaning the bone marrow is releasing less-mature cells into circulation in response to a site of injury (increased in acute infection and inflammation). Life span: 2 to 14 days Copyright © 2011, 2007 by Mosby, Inc., an affiliate of Elsevier Inc. 24

Leukocytes Granulocytes Eosinophils Account for only 2% to 4% of all WBCs Have a reduced ability for phagocytosis compared with neutrophils Granules contain histamine. Engulf antigen-antibody complexes formed during an allergic response An elevation of eosinophils is also seen in some neoplastic disorders, such as Hodgkin’s lymphoma, various skin diseases, and connective tissue disorders. Copyright © 2011, 2007 by Mosby, Inc., an affiliate of Elsevier Inc. 25

Leukocytes Granulocytes Basophils Make up less than 2% of all leukocytes Limited role in phagocytosis Have cytoplasmic granules that contain heparin, serotonin, and histamine When stimulated by an antigen, basophils release their granules. Copyright © 2011, 2007 by Mosby, Inc., an affiliate of Elsevier Inc. 28

Basophils on Wright’s stained slides.
Leukocytes Basophils on Wright’s stained slides. Note normal RBC on slide on right and hypochromic (low hemoglobin) RBC on slide on left. Copyright © 2011, 2007 by Mosby, Inc., an affiliate of Elsevier Inc. 29

Leukocytes Agranulocytes Lymphocytes Form the basis of cellular and humoral immune responses Two subtypes of lymphocytes are B cells and T cells. {Details of lymphocyte function are presented in Chapter 14.} Copyright © 2011, 2007 by Mosby, Inc., an affiliate of Elsevier Inc. 30

Leukocytes Agranulocytes Monocytes Potent phagocytic cells Second type of cell to arrive at site of injury When monocytes migrate into tissue, they become macrophages. Copyright © 2011, 2007 by Mosby, Inc., an affiliate of Elsevier Inc. 31

Lymphocyte on Wright’s stained slide.
Leukocytes Lymphocyte on Wright’s stained slide. Copyright © 2011, 2007 by Mosby, Inc., an affiliate of Elsevier Inc. 32

Monocyte on Wright’s stained slide.
Leukocytes Monocyte on Wright’s stained slide. Copyright © 2011, 2007 by Mosby, Inc., an affiliate of Elsevier Inc. 33

Leukocytes Macrophages: Monocytes that have migrated into tissue Resident macrophages Called Kupffer cells when in liver Called osteoclasts when in bone Called alveolar macrophages when in lung Copyright © 2011, 2007 by Mosby, Inc., an affiliate of Elsevier Inc. 34

Thrombocytes (Platelets)
Primary function is to initiate clotting process by producing plug at site of injury. Thrombocytes are released into circulation by cells in the bone marrow called megakaryocytes. Platelets must be available in sufficient numbers and must be structurally and metabolically sound for blood clotting to occur. Copyright © 2011, 2007 by Mosby, Inc., an affiliate of Elsevier Inc. 35

Thrombocytes (Platelets)
Have a life span of only 5 to 9 days Participate in clot shrinkage and retraction Platelet production is regulated in part by thrombopoietin, a growth factor that acts on bone marrow to stimulate platelet production. It is produced in the liver, kidneys, smooth muscle, and bone marrow. Copyright © 2011, 2007 by Mosby, Inc., an affiliate of Elsevier Inc. 36

Hemostasis Normal blood clotting mechanisms minimize blood loss after injury. Four components of normal hemostasis Vascular response Platelet plug formation Development of fibrin clot on platelet plug by plasma clotting factors Lysis of clot Copyright © 2011, 2007 by Mosby, Inc., an affiliate of Elsevier Inc. 37

Hemostasis Vascular response Immediate local vasoconstrictive response of injured blood vessels Reduces leakage of blood from the injured vessel by reducing vessel size Vasoconstriction gives time for platelet response and plasma clotting factors to be triggered. Vascular spasm may last for 20 to 30 minutes, allowing time for the platelet response and plasma clotting factors to be activated. The platelet response and plasma clotting factors are triggered by endothelial injury and the release of substances such as tissue factor (TF). Copyright © 2011, 2007 by Mosby, Inc., an affiliate of Elsevier Inc. 38

Hemostasis Platelet plug formation Activated by exposure to interstitial collagen from the injured blood vessel Platelet stickiness is called adhesiveness. Formation of clumps is termed aggregation or agglutination. Platelets facilitate the reactions of the plasma clotting factors. When a blood vessel is injured, circulating platelets are exposed to collagen from the inner lining of the vessel. This interaction causes the platelets to release substances such as platelet factor 3 and serotonin, which facilitate coagulation. At the same time, platelets release adenosine diphosphate, which increases platelet adhesiveness and aggregation, thereby enhancing the formation of a platelet plug. In addition, von Willebrand factor (vWF) is important in forming an adhesive bridge between platelets and vascular subendothelial structures. It is synthesized in endothelial cells and megakaryocytes and acts as a carrier for factor VIII. Copyright © 2011, 2007 by Mosby, Inc., an affiliate of Elsevier Inc. 39

Coagulation Mechanism
Fig Coagulation mechanism showing steps in the intrinsic pathway and extrinsic pathway as it would occur in the test tube. HMWK, High-molecular-weight kininogen; RBCs, red blood cells. Copyright © 2011, 2007 by Mosby, Inc., an affiliate of Elsevier Inc. 40

Hemostasis Plasma clotting factors Form a visible fibrin clot on the platelet plug Are labeled with both names and Roman numerals Are always present in circulation in inactive forms until stimulated to initiate clotting through one of two pathways Copyright © 2011, 2007 by Mosby, Inc., an affiliate of Elsevier Inc. 41

Hemostasis Plasma clotting factors (cont'd) Two pathways of clotting Intrinsic pathway is activated by collagen exposure. Extrinsic pathway is initiated when tissue factor or tissue thromboplastin is released from injured tissue. Copyright © 2011, 2007 by Mosby, Inc., an affiliate of Elsevier Inc. 42

Hemostasis Plasma clotting factors (cont'd) Thrombin is the most powerful enzyme in the coagulation process because it converts fibrinogen to fibrin, an essential component of a blood clot. Copyright © 2011, 2007 by Mosby, Inc., an affiliate of Elsevier Inc. 43

Hemostasis Lysis of clot Anticoagulation, the reverse of clotting, helps keep blood fluid. Anticoagulation occurs by two means. Antithrombins: Interfere with thrombin Fibrinolysis: Process that results in dissolution of the fibrin clot Endogenous heparin is an example of an anticoagulant. Other anticoagulants are protein C and protein S. The fibrinolytic system is initiated when plasminogen is activated to plasmin (see next slide). Thrombin is one of the substances that can activate the conversion of plasminogen to plasmin, thereby promoting fibrinolysis. The plasmin attacks either fibrin or fibrinogen by splitting the molecules into smaller elements known as fibrin split products (FSPs) or fibrin degradation products (FDPs). If fibrinolysis is excessive, the patient will be predisposed to bleeding. In such a situation, bleeding results from the destruction of fibrin in platelet plugs or from the anticoagulation effects of increased FSPs. Increased FSPs lead to impaired platelet aggregation, reduced prothrombin, and an inability to stabilize fibrin. Copyright © 2011, 2007 by Mosby, Inc., an affiliate of Elsevier Inc. 44

Spleen Located in the upper left quadrant next to kidney Functions can be classified as Hematopoietic: Able to produce RBCs during fetal development Copyright © 2011, 2007 by Mosby, Inc., an affiliate of Elsevier Inc. 46

Spleen Functions (cont'd) Filtration Removes old and damaged RBCs from circulation Removes hemoglobin from RBCs and returns iron component to the bone marrow for reuse Filters out bacteria, especially encapsulated organisms Copyright © 2011, 2007 by Mosby, Inc., an affiliate of Elsevier Inc. 47

Spleen Functions (cont'd) Immunologic: Contains a rich supply of lymphocytes, monocytes, and stored immune globulins Storage: Stores RBCs and approximately 30% of total mass of platelets A person who has had a splenectomy has higher circulating levels of platelets than a person who still has his or her spleen. Copyright © 2011, 2007 by Mosby, Inc., an affiliate of Elsevier Inc. 48

Lymph System Protein and fat from the GI tract and certain hormones are returned to circulatory system. Returns excess interstitial fluid to the blood to prevent or reduce edema Copyright © 2011, 2007 by Mosby, Inc., an affiliate of Elsevier Inc. 50

Lymph System Lymph fluid Pale yellow interstitial fluid that has diffused through capillary walls Circulates through special vasculature Too much interstitial fluid or reduced absorption leads to lymphedema May occur as a complication of mastectomy or lumpectomy Copyright © 2011, 2007 by Mosby, Inc., an affiliate of Elsevier Inc. 51

Lymph System Lymphatic capillaries Thin-walled vessels with irregular diameter Larger than blood capillaries but without valves A figure that shows lymph drainage throughout the body is available on the website for this chapter at Copyright © 2011, 2007 by Mosby, Inc., an affiliate of Elsevier Inc. 52

Lymph System Lymphatic capillaries (cont’d) Unite to form lymphatic vessels that carry all lymph fluid to the right lymphatic duct or the thoracic duct These larger vessels drain into subclavian veins in the neck. Copyright © 2011, 2007 by Mosby, Inc., an affiliate of Elsevier Inc. 53

Lymph System Lymph nodes Small clumps of lymphatic tissue found in groups along lymph vessels at various sites More than 200 lymph nodes throughout the body Largest concentration of lymph nodes is in the abdomen surrounding the GI tract. Copyright © 2011, 2007 by Mosby, Inc., an affiliate of Elsevier Inc. 54

Lymph System Lymph nodes (cont'd) Primary function is filtration of pathogens and foreign particles carried by lymph fluid. Located both superficially and deep Copyright © 2011, 2007 by Mosby, Inc., an affiliate of Elsevier Inc. 55

Lymph System Liver Acts as a filter Produces all the procoagulants essential for hemostasis and blood coagulation Stores excess iron Produces hepcidin, a key regulator of iron balance The synthesis of hepcidin is stimulated by iron overload or inflammation. Hepcidin reduces the release of stored iron from enterocytes (in the intestines) and macrophages. Copyright © 2011, 2007 by Mosby, Inc., an affiliate of Elsevier Inc. 56

Audience Response Question While reviewing the results of a 76-year-old patient’s complete blood count (CBC), which of the following findings would be of greatest concern to the nurse? 1. Platelets of 400,000/μL 2. Hemoglobin of 11.4 g/dL 3. White cell count of 3000/μL 4. Red cell count of 4.5 × 106/μL Answer: 3 Rationale: A white blood cell count of 3000/μL is low (leukopenia); the patient is at risk for infection. The hemoglobin is low but not at a critical level. The platelet count and red blood cell count are within the normal range. Copyright © 2011, 2007 by Mosby, Inc., an affiliate of Elsevier Inc. 62

Audience Response Question To evaluate the effectiveness of treatment for a patient with thrombocytopenia, the nurse plans to monitor the: 1. Platelet count. 2. Prothrombin time. 3. Partial thromboplastin time. 4. International normalized ratio (INR). Answer: 1 Rationale: Thrombocytopenia is a platelet count of less than 100,000/μL. Copyright © 2011, 2007 by Mosby, Inc., an affiliate of Elsevier Inc. 63

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