Anatomy and Physiology Ch. 17 Blood – Flashcards
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What type of tissue is blood?
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Specialized connective tissue.
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What percentage of whole blood is plasma?
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55%
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% of blood erythrocytes?
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45%
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% of blood thrombocytes and leukocytes?
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<1%
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What is Plasma?
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Non-living fluid matrix (water, hormones, nutrients)
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What are formed elements?
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Living blood cells suspended in matrix
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What are the functions of blood?
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Distribution, Regulation, and Protection.
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3 Distribution functions of blood?
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1. Delivering oxygen and nutrients to all body cells. 2. Transporting metabolic wastes from tissues to lungs and kidneys. 3. Transporting hormones from endocrine glands to target organs.
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3 Regulation functions of blood?
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1. Body temp. by absorbing and distributing heat (38-100.5 celsius) 2. pH (7.4) maintained by buffers in blood 3. Maintaining adequate fluid volume.
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2 Protection functions of blood?
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1. Prevention of blood loss (clots) 2. Preventing infection (antibodies, complement proteins, WBCs)
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How much average blood do males and females have?
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males = 5-6L females = 4-5L
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What are the different cell types found in blood?
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Erythrocytes, Leukocytes, Thrombocytes
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What is hematocrit and what could influence it?
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Percent blood volume that is RBCs Muscle mass, physical activity, altitude, environment
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What components make up plasma?
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Water, proteins (Albumin, Globulins, Fibrinogen), Nitrogenous by-products of metabolism, electrolytes, Respiratory gases, Hormones
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What is the point of origination for formed elements?
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bone marrow
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What is spectrin?
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Protein on the surface of RBC that provides flexibility and ability to change shape.
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What is the structure of hemoglobin?
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Protein globin bound to red pigment heme Globin - 2 alpha and 2 beta polypeptide chains; each binds to ring-like heme unit with Fe in middle of heme unit
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Role of Iron in oxygen transport?
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binds with oxygen
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What is hematopoiesis and where does it occur?
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Blood cell formation; Occurs in red bone marrow or axial skeleton, girdles, proximal epiphyses of humerus and femur.
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What is the average amount of blood produced each day?
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1 ounce per day (2 million cells/sec)
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What are hemocytoblasts?
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Stem cells in red marrow that give rise to ALL blood cells
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What is erythropoiesis?
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Erythrocyte production. (Genesis of erythrocytes)
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What are reticulocytes?
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Young RBCs that contain a small number of ribosomes; later lose ribosomes to become mature RBCs.
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What are the phases of erythrocyte development?
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1. Ribosome synthesis (early erythroblast) 2. Hemoglobin accumulation (late erythroblast) 3. Ejection of nucleus and formation of reticulocytes; results in biconcave shape
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What is erythropoietin?
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Hormone released by the kidneys during hypoxic conditions that stimulates the release of RBCs into the bloodstream.
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What are the effects of Erythropoietin?
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1. More rapid maturation of committed bone marrow cells. 2. Increase circulating reticulocyte count in 1-2 days
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What effect does testosterone have on RBC production?
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enhances EPO production, resulting in higher RBC counts in males.
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What is the life span of RBCs?
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100-120 days
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What organ is involved in RBC destruction?
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Spleen
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What happens to iron after a RBC has been destroyed?
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It is salvaged for reuse.
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What is anemia?
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When blood has low oxygen carrying capacity.
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What are the causes of anemia?
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1. Insufficient RBCs 2. Low Hemoglobin count 3. Abnormal Hemoglobin
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What are the causes of insufficient RBCs?
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1. Hemorrhagic anemia - Acute or Chronic blood loss 2. Hemolytic anemia - RBCs rupture prematurely 3. Aplastic anemia - Destruction or inhibition of red bone marrow
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What are the causes of low Hb count?
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1. Iron Deficiency anemia 2. Pernicious anemia - deficiency of B12 or inability to absorb it.
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What are the causes of abnormal Hb?
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1. Thalassemias - RBCs are thin and delicate due to faulty or missing globin chain (Mediterranean) 2. Sickle cell anemia - Abnormal Hb causes cell to be crescent shaped in lox oxygen situations.
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What is polycythemia?
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Excessive number of RBCs. Increase blood viscosity.
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What are the causes of polycythemia?
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1. Polycythemia vera - bone marrow cancer that leads to increased RBC production 2. Secondary polycythemia - when less oxygen is available (high alt.) and/or when EPO production increases 3. Blood doping - removing blood from the system allowing body to replace missing RBCs then re-injecting.
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What is diapedesis?
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movement of WBCs out of the bloodstream into surrounding tissues.
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What is leukocytosis?
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An immune response that occurs when WBC count is over 11,000 cells/microliter (normal=5,000-10,000)
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What are granulocytes, and what are the different types?
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Contain cytoplasmic granules; Neutrophils, Eosinophils, and Basophils Characteristic = Larger but shorter lived than RBCs; Lobed nuclei; Phagocytic
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What are Neutrophils and their function?
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Most numerous WBCs; granules contain hydrolytic enzymes or defensins; function is to phagocytize bacteria.
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What are Eosinophils and their function?
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Their granules contain an array of digestive enzymes and they kill invading parasitic worms and are involved in allergic reactions.
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What are Basophils and their function?
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Their granules are an inflammatory chemical that acts as a vasodilator and attracts other WBCs (histamine). They release histamines and initiate inflammation.
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What are Agranulocytes and the different types?
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They lack granules. Lymphocytes and monocytes.
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Where are lymphocytes found?
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in lymphoid tissues, nodes, vessels, spleen.
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What are T-cells?
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T-lymphocytes; they are directly involved with tunor and virus infected cells.
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What are B-cells?
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B-lymphocytes; they release antibodies into blood.
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What do monocytes do?
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They phagocytize viruses, bacterial parasites, and they activate lymphocytes.
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What is leukopoiesis?
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The production of WBCs stimulated by chemical messengers released by bone marrow and mature WBCs.
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What is leukemia?
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Cancerous condition in which red bone marrow becomes overrun with WBCs; results i immature WBCs flooding the bloodstream. Results in internal hemorrhaging and overwhelming infections.
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How are different types of leukemia determined?
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By the type of dysfunctional WBC.
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What is acute leukemia?
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It is derived from -blast type cells, and it is rapid and affects children.
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What is chronic leukemia?
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Derived from later cell stages (myelocytes and band cells) Slow and affects older population.
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What are megakaryocytes?
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Large cells that break up to form platelets.
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What is thrombopoietin?
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Hormone that regulates platelet formation.
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What is hemostasis?
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A fast series of reactions to stop blood flow when break occurs in one of blood vessels.
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What are the three stages of hemostasis?
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1. Vascular spasm 2. Platelet plug formation 3. Coagulation
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Explain Vascular spasm
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Damaged vessels constrict (vasocontriction). Function is to reduce blood flow to allow time for formation of a platelet plug.
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Explain Platelet plug formation
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Collagen fibers underneath endothelial cells become exposed, and platelets stick to the fibers. Von Willebrand factor is a protein that helps form a bridge between platelets and fibers.
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What changes in platelets occur during platelet plug formation?
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The platelets become larger, form processes (arms) to attract other platelets, and release ADP, serotonin, and thromoxane A2
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What are the phases of coagulation?
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1. Prothrombin Activator is formed. 2. Prothrombin is converted into the enzyme thrombin 3. Thrombin catalyzes joining of fibrinogen to form a fibrin mesh.
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What are the roles of actin and myosin in clot retraction?
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They cause the platelets to contract and pull on the fibrin strands. The severed edges of the vessels are pulled together.
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What is the role of platelet derived growth factor (PDGF) in vessel repair?
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Stimulates division of smooth muscle cells and fibroblasts to rebuild vessel wall.
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What is the role of fibroblasts in vessel repair?
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Form connective tissue patch in injured area.
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What is the role of Vascular endothelial growth factor (VEGF) in vessel repair?
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Stimulates endothelial cells to multiply and restore normal flow.
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What occurs during fibrinolysis?
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Removes uneeded clots when healing has occured
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What is the role of plasmin?
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It is the enzyme responsible for digesting cells
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What is a thrombus?
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A clot that develops and persists in unbroken vessel. Result=blocks circulation and leads to tissue death
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What is an embolus?
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A freely floating thrombus
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What is embolism?
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An embolus that has encountered and obstructed a narrow vessel; could cause vessel to rupture (stroke)
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What are gylcoproteins?
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Unique markers that allow immune cells to decipher foreign from domestic
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What determines an individual's blood type?
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The antigens on the surface of cells.
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What is erythroblastosis fetalis?
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Occurs when a pregnant mother's Rh negative antibodies cross the placenta and attack the RBCs of her unborn child.
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Where are blood cells first formed in the fetus?
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in the fetal yolk sac
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What are blood islands?
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Mesenchymal cells that fetal blood cells develop from
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What type of Hb does a fetus possess and why?
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Hemoglobin F - has a higher affinity for oxygen than adult Hb.
