Blood Summary – Flashcards
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Blood is composed of
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formed elements and plasma
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Hematocrit is a measure of
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one formed element, erythrocytes, as a % of total blood volume.
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Blood's physical characteristics and volume
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viscous, slightly alkaline fluid representative about 8% of total body weight normal adult blood volume is about 5 L
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Distribution functions of blood include
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1.) delivery of oxygen and nutrients to body tissues 2.) removal of metabolic wastes 3.) transport of hormones
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Regulation functions of blood are
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maintenence of: 1.) body temperature 2.) constant blood of pH 3.) adequate fluid volume
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Protective functions of blood are
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1.) hemostasis 2.) prevention of infection
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Blood plasma is what color and
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stra-colored, viscous fluid 90% water
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the remaining 10% of blood plasma is
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solutes such as nutrients, respiratory gases, salts, hormones, proteins
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plasma makes up what percent of whole blood?
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55%
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Plasma proteins are made by what organ
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liver
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plasma proteins include
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albumin globulins fibrinogen
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albumin is an important
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blood buffer and contributes to the osmotic pressure of blood.
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formed elements account for what percent of whole blood? and what are they?
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45% - erythrocytes - leukocytes - platelets
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all formed elements in the blood arise from
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hemocytoblasts in the bone marrow
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Erythrocytes (RBCs) are
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small, biconcave cells containing large amounts of hemoglobin have no nucleus few organelles
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what allows RBCs to change shape as they pass through capillaries?
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spectrin
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what's the major function of RBCs?
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oxygen support
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in the lungs, oxygen binds to what and what does it produce?
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hemoglobin molecules, oxyhemoglobin
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in body tissues, oxygen disassociates from what and what does it produce?
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iron, deoxyhemoglobin
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what do RBCs begin as?
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hemocytoblasts
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erythropoiesis stages
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1.) hemocytoblasts 2.) proerythroblast (committed cell) 3.) erythroblast (early and late stages) 4.) normoblast 5.) reticulocyte
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during the erythropoiesis process, what happens?
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hemoglobin accumulates and the organelles and nucleus are extruded differentiation of reticulocytes is completed in the bloodstream
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what 2 things enhance erythropoiesis?
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erythropoietin (EPO) and testosterone
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erythropoiesis
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the process of producing red blood cells by the stem cells in the bone marrow
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erythropoietin EPO
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A hormone produced and released by the kidney that stimulates the production of red blood cells by the bone marrow.
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what 3 things are essential for production of hemoglobin?
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1.) Iron 2.) vitamin B12 3.) folic acid
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How many days make up the RBCs life span?
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120 days
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How are old and damaged erythrocytes removed from circulation?
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by macrophages of the liver and spleen
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what is released iron from hemglobin stored as?
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ferritin or hemodestrin to be reused
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the balance of the heme group is degraded to and secreted in what?
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billirubin and secreted in bile
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amino acids of globin are...
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metabolized or recycled
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Erythrocyte disorders include
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anemia and polycythemia
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leukocytes are
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WBCs, all are nucleated and have crucial roles in defending against disease.
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two main leukocyte categories:
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1.) granulocyte 2.) agranulocytes
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Granulocytes include
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Neutrophils Eosinophils Basophils
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Basophils contain what?
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contain histamine
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histamine does 2 things
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enhances migration of leukocytes to inflammatory sites and promotes vasodilation
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Neutrophils
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are active phagocytes against bacteria
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Eosinophils
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attack parasitic worms and their numbers increase during allergic reactions
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Agranulocytes
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have crucial roles in immunity - lymphocyts = immune cells - monocytes = differentiate into macrophages
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Leukopoiesis
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is directed by colony-stimulating factors ad interleukins released by supporting cells of the bone marrow and mature WBCs
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Leukopoiesis
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the formation of white blood cells, begins in the marrow.
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Leukocyte disorders
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include leukemias and infectious mononucleosis
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Platelets
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fragments of large, megakaryocytes formed in red marrow.
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role of platelets when a blood cell is damaged
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form a plug to help prevent blood loss and play a central role in the clotting cascade
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Hemostasis
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prevention of blood loss
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the 3 major phases of hemostasis
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1.) vascular spasm 2.) platelet plug formation 3.) coagulation
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What do spasms of smooth muscle in blood vessel walls and accumulation of platelets (platelet plug) at the site of vessel injury provide?
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a temporary means of stopping blood loss until coagulation occurs
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coagulation of blood may be initiated by either the
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intrinsic or extrinsic pathways
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Platelet phospholipid PF3
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is crucial to both intrinsic or extrinsic pathways.
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Tissue Factor TF (Factor III)
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exposed by tissue injury allows the extrinsic pathway to bypass many steps of the intrinsic patway
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a series of activated procoagulants oversees the
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intermediate steps of each coagulation cascade
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the pathways converse as
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prothrombin is converted to thrombin
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what happens after a clot is formed?
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clot retraction occurs
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what happens during clot retraction?
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serum is squeeze out and the ruptured vessel edges are drawn together
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how is the vessel repaired?
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by smooth muscle, connective tissue, and endothelial cell proliferation and migration
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fibrinolysis
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clot digestion that occurs when healing is complete
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abnormal expansion of clots is prevented by
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removal of coagulation factors in contact with rapidly flowing blood by inhibition of activated blood factors.
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Prostacyclin PGI2 & NO
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secreted by endothelial cells help prevent undesirable clotting
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Thromboembolic disorders
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involved undesirable clot formation which can blood vessels
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DIC
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is a condition of body wide clotting in undamaged blood vessels and subsequent hemorrhages, disseminated intravascular coagulation
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Thrombocytopenia
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a deficit of platelets, causes spontaneous bleeding from small blood vessels
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Thrombocytopenia
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a bleeding disorder characterized by an abnormal decrease in the number of platelets in the blood, which impairs the clotting process
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petechiae
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Small, pinpoint hemorrhages
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Hemophilia
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sex-linked recessive disorder defined by the absence of one or more proteins required for blood clotting is caused by a genetic deficiency of certain coagulation factors.
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liver disease can cause
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bleeding disorders because many coagulation proteins are formed by this organ
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whole blood transfusions
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are given to replace severe and rapid blood loss.
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packed RBCs are given to
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replace lost O2 carrying capacity
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blood group is based on
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agglutinogens (antigens) present on red blood cell membranes
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when mismatched blood is transfused,
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the recipients agglutinins (plasma antibodies) clump the foreign RBCs
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the clumped cells
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are lysed
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blood vessels may be blocked by
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clumped RBCs
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released hemoglobin may precipitate in
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the kidney tubules, causing renal shutdown
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before whole blood can be transfused,
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it must be typed and cross matched so that transfusion reactions are avoided.
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the most important blood groups for which blood must be typed are
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ABO and Rh types
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plasma volume can be replaced with
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balanced electrolyte solutions and these are generally preferred over plasma expanders
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diagnostic blood tests
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can provide large amounts of information about the current status of the blood and of the body as a whole
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erythropoietin
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the hormonal stimulus that prompts RBC formation
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the WBC that can become an antibody secreting cell is the
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lymphocyte
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factor XI does not
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promote multiple steps in the clotting pathway
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the normal pH of blood is about
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7.4
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suppose your blood was AB positive,
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- agglutinogens A and B are present on your RBCs - there are not anti-A or anti-B antibodies in your plasma - your blood is Rh+
