Copyright © 2014 Wolters Kluwer Health | Lippincott Williams & Wilkins Chapter 25 Blood Cells and the Hematopoietic System

Copyright © 2014 Wolters Kluwer Health | Lippincott Williams & Wilkins Elements of the Hematopoietic System All the blood cells and their precursors The bone marrow, where blood cells have their origin The lymphoid tissues where some blood cells circulate as they develop and mature

Copyright © 2014 Wolters Kluwer Health | Lippincott Williams & Wilkins Composition of Blood Fluid/dissolved components –Water –Proteins –Small molecular substances Cellular elements –Red blood cells –Thrombocytes or platelets –White blood cells Lymphocytes Leukocytes

Copyright © 2014 Wolters Kluwer Health | Lippincott Williams & Wilkins Question All of the following are cellular components of blood except which one? –A. Macrophages –B. Mast cells –C. Neutrophils –D. Eosinophils

Copyright © 2014 Wolters Kluwer Health | Lippincott Williams & Wilkins Answer B. Mast cells Mast cells are not blood cells; rather they are found in connective tissue and initiate the inflammatory response.

Copyright © 2014 Wolters Kluwer Health | Lippincott Williams & Wilkins Function of the Plasma Components of Blood Carry the cells that transport gases Aid in body defenses Prevent blood loss

Copyright © 2014 Wolters Kluwer Health | Lippincott Williams & Wilkins Plasma Proteins Albumin –Comprises approximately 54% of the plasma proteins –Contributes to plasma osmotic pressure and the maintenance of blood volume –Serves as a carrier for certain substances

Copyright © 2014 Wolters Kluwer Health | Lippincott Williams & Wilkins Plasma Proteins (cont.) Globulins –Comprise approximately 38% of plasma proteins Alpha globulins transport bilirubin and steroids –Beta globulins transport iron and copper. –Gamma globulins constitute the antibodies of the immune system.

Copyright © 2014 Wolters Kluwer Health | Lippincott Williams & Wilkins Plasma Proteins (cont.) Fibrinogen –Makes up approximately 7% of the plasma proteins –Is converted to fibrin in the clotting process

Copyright © 2014 Wolters Kluwer Health | Lippincott Williams & Wilkins Neutrophils Constitute 50% to 60 % of white blood cells Primarily responsible for maintaining normal host defenses against invading substances –First cells to arrive at the site of infection –Have their origins in the myeloblasts found in the bone marrow –Move to the tissue for approximately 1 to 3 days Die in the tissue discharging phagocytic function or die of senescence

Copyright © 2014 Wolters Kluwer Health | Lippincott Williams & Wilkins Eosinophils 1% to 3% of the total number of white blood cells Increase in number during allergic reactions and parasitic infections –The agents associated with allergic reactions –In parasitic infections, the eosinophils use surface markers to attach themselves to the parasite and then release hydrolytic enzymes.

Copyright © 2014 Wolters Kluwer Health | Lippincott Williams & Wilkins Basophils 0.3% to 0.5% of the total leukocytes Consist of heparin, an anticoagulant, histamine, a vasodilator, and other mediators of inflammation Similar to mast cells Involved in allergic and hypersensitivity reactions

Copyright © 2014 Wolters Kluwer Health | Lippincott Williams & Wilkins Lymphocytes 20% to 30% of the total blood leukocytes Function in the lymph nodes or spleen to defend against microorganisms through the immune response Three types –B lymphocytes –T lymphocytes –Natural killer cells

Copyright © 2014 Wolters Kluwer Health | Lippincott Williams & Wilkins Monocytes and Macrophages 3% to 8% of the total leukocyte count Cells survive for months to years in the tissues. Important role in chronic inflammation Involved in the immune response –Activating lymphocytes –Presenting antigen to T cells

Copyright © 2014 Wolters Kluwer Health | Lippincott Williams & Wilkins Thrombocytes Circulating cell fragments of the large megakaryocytes Function to form the platelet plug to helps control bleeding 8 to 9 days in circulation

Copyright © 2014 Wolters Kluwer Health | Lippincott Williams & Wilkins Hematopoiesis Blood cells originate from pluripotent stem cells in the bone marrow. The proliferation, differentiation, and functional abilities of the various blood cells are controlled by cytokines. –Cytokines are hormone-like growth factors.

Copyright © 2014 Wolters Kluwer Health | Lippincott Williams & Wilkins Useful Hematopoietic Growth Factors EPO TPO G-CSF GM-CSF

Copyright © 2014 Wolters Kluwer Health | Lippincott Williams & Wilkins Conditions Responding to Use of Hematopoietic Growth Factors Infectious diseases such as acquired immunodeficiency syndrome (AIDS) Congenital and myeloproliferative disorders Some solid tumors Bone marrow failure caused by chemotherapy or aplastic anemia Anemia of kidney failure Hematopoietic neoplasms

Copyright © 2014 Wolters Kluwer Health | Lippincott Williams & Wilkins Hematopoietic Growth Factors Increase peripheral stem cells for transplantation Accelerate cell proliferation after bone marrow engraftment

Copyright © 2014 Wolters Kluwer Health | Lippincott Williams & Wilkins Question Is the following statement true or false? Hematopoietic growth factors are only associated with normal production of cells.

Copyright © 2014 Wolters Kluwer Health | Lippincott Williams & Wilkins Answer False In disease states such as polycythemia vera, leukemia, and other blood cancers, inappropriate production of growth factors does occur.

Copyright © 2014 Wolters Kluwer Health | Lippincott Williams & Wilkins The Complete Blood Count A complete blood count provides information regarding the number of blood cells and their structural and functional characteristics. The white cell differential count is the determination of the relative proportions (percentages) of individual white cell types.

Copyright © 2014 Wolters Kluwer Health | Lippincott Williams & Wilkins Diagnostic Tests A complete blood count (CBC) is a commonly performed screening test that determines the number of red blood cells, white blood cells, and platelets per unit of blood.

Copyright © 2014 Wolters Kluwer Health | Lippincott Williams & Wilkins Obtaining Blood Specimens Skin puncture (capillary blood) Venipuncture Arterial puncture Bone marrow aspiration

Copyright © 2014 Wolters Kluwer Health | Lippincott Williams & Wilkins Diagnostic Tests Blood count Erythrocyte sedimentation rate Bone marrow aspiration and biopsy