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Anatomy 2 Ch2
Blood crap
| Question | Answer |
|---|---|
| Function of blood | Transportation– O2, CO2, metabolic wastes, nutrients, heat & hormones•Regulation–helps regulate pH through buffers–helps regulate body temperature–helps regulate water content of cells •Protection from disease & loss of blood |
| Physical Characteristics of Blood | Thicker flows more slowly than water•Temperature of 100.4 •pH 7.4 (7.35-7.45)•8 % of total body weight•Blood volume–5 to 6 liters in male–4 to 5 liters in female–hormonal negative feedback systems maintain constant blood volume and osmotic pressure |
| Components of blood | 55% plasma–92% water–8% solutes•45% cells –99% RBCs–< 1% WBCs and platelets |
| Blood plasma | Over 90% water and•7% plasma proteins created in liver and confined to bloodstream [albumin,globulins, fibrinogen] |
| Albumin: | maintain blood osmotic pressure |
| globulins | (immunoglobulins)•antibodies bind to foreign substances called antigens |
| Fibrinogen: | for clotting |
| 2% other substances in blood plama | electrolytes, nutrients, hormones, gases, waste products |
| Hematocrit | proportion, by volume, of the blood that consists of red blood cells. |
| Percentage of blood occupied by cells– | female normal range•38 - 46% (average of 42%)–male normal range•40 - 54% (average of 46%)•testosterone |
| Anemia | not enough RBCs or not enough hemoglobin |
| Polycythemia– | too many RBCs (over 65%)–dehydration, tissue hypoxia, blood doping in athletes |
| Formed elements of blood | Red blood cells (erythrocytes)•White blood cells (leukocytes)•Platelets (special cell fragments) |
| Formation of blood cells in embryo | occurs in yolk sac, liver, spleen, thymus, lymph nodes & red bone marrow |
| Formation of blood cells in adults | occurs only in red marrow of flat bones like sternum, ribs, skull & pelvis and ends of long bones |
| Hematopoiesis | production of blood cells and platelets, which occurs in the bone marrow. |
| Hemopoietic Growth Factors | Regulate differentiation & proliferation |
| Erythropoietin (EPO)– | produced by the kidneys increase RBC precursors |
| Thrombopoietin (TPO)– | hormone from liver stimulates platelet formation |
| Cytokines | local hormones of bone marrow–produced by some marrow cells to stimulate proliferation in other marrow cells–colony-stimulating factor (CSF) & interleukin stimulate WBC production |
| Erythropoiesis | Erythrocyte formation occurs in adult red bone marrow of certain bones |
| The main stimulus for erythropoiesis is | hypoxia |
| _____ starts to produce hemoglobin. Many steps later, nucleus is ejected & a____is formed –orange i | Proerythroblast; reticulocyte |
| Reticulocytes escape from | bone marrow into the blood |
| Tissue hypoxia | (cells not getting enough O2)–high altitude–anemia–circulatory problems |
| Anemia | RBC production falls below RBC destruction |
| Kidney response to hypoxia– | release erythropoietin–speeds up development of proerythroblasts into reticulocytes |
| RBCs live | 120 days. wear out from bending to fit through capillaries–no repair possible due to lack of organelles |
| Worn out red blood cells are | removed by fixed macrophages in spleen & liver•Breakdown products are recycled |
| Red Blood Cells (Erythrocytes) | Contain oxygen-carrying protein hemoglobin that gives blood red color–1/3 of cell’s weight is hemoglobin•Biconcave disk 8 microns in diameter–increased surface area/volume ratio –flexible shape for narrow passages–no nucleus or organelles, no cell divide |
| Normal RBC count | male 5.4 million/drop - female 4.8 million/drop–new RBCs enter circulation at 2 million/second |
| Hemoglobin | Globin protein consisting of 4 polypeptide chains•One heme pigment attached to each polypeptide chain–each heme contains an iron ion (Fe+2) that can combine reversibly with one oxygen molecule |
| Transport of O2, CO2 and Nitric Oxide | Each hemoglobin molecule can carry 4 oxygen molecules•Hemoglobin transports 23% of total CO2 waste•Hemoglobin transports nitric oxide & super nitric oxide helping to regulate BP |
| Iron(Fe+3) | stored in liver, muscle or spleen–in bone marrow being used for hemoglobin synthesis |
| Heme: | Converted to bilirubin (yellow) secreted by liver into bile •converted to stercobilin (brown pigment in feces) by bacteria of large intestine•if reabsorbed from intestines into blood is converted to a yellow pigment, urobilin and excreted in urine |
| Leukocytes (WBCs) | nucleated cells and do not contain hemoglobin. |
| Granular leukocytes: | eosinophils, basophils, and neutrophils |
| Agranular leukocytes: | lymphocytes and monocytes |
| Majorhistocompatibility antigens (MHC) | Surface proteins that are unique for each person –Can be used to identify a tissue |
| WBC Physiology | Less numerous than RBCs–5000 to 10,000 cells per drop of blood. Only 2% of total WBC population is in circulating blood at any given time–rest is in lymphatic fluid, skin, lungs, lymph nodes & spleen |
| Leukocytosis | high white blood cell count–microbes, strenuous exercise, anesthesia or surgery |
| Leukopenia | low white blood cell count–radiation, shock or chemotherapy |
| Function of WBCs | Different WBCs combat inflammation and infection in different ways. |
| Neutrophils | and wandering or fixed macrophages (which develop from monocytes) combat through phagocytosis. |
| Eosinophils | combat the effects of histamine in allergic reactions, phagocytize antigen-antibody complexes, and combat parasitic worms. |
| Basophils | develop into mast cells that liberate heparin, histamine, and serotonin in allergic reactions that intensify the inflammatory response. |
| B lymphocytes | In response to the presence of foreign substances called antigens, differentiate into tissue plasma cells that produce antibodies. |
| T lymphocytes | destroy foreign invaders directly |
| WBCs leave the blood stream by | emigration |
| chemotaxis. | The chemical attraction of WBCs to a disease or injury site |
| Emigration in WBCs | WBCs roll along endothelium, stick to it & squeeze between cells.–adhesion molecules displayed near site of injury (selectins) help WBCs stick to endothelium–molecules (integrins) found on neutrophils assist in movement through wall |
| Phagocytosis in WBCs | Neutrophils & macrophages phagocytize bacteria & debris–chemotaxis of both |
| Neutrophils (Granulocyte) | Nuclei = 2 to 5 lobes connected by thin strands–older cells have more lobes•Diameter is 10-12 microns •60 to 70% of circulating WBCs•Fastest response of all WBC to bacteria |
| Neutrophils Direct actions against bacteria by releasing: | Lysozymes which destroy/digest bacteria–Defensin proteins that act like antibiotics & poke holes in bacterial cell walls destroying them–Strong oxidants (bleach-like, strong chemicals ) that destroy bacteria |
| Basophils (Granulocyte) | Large, dark purple, variable-sized granules stain with basic dyes–obscure the nucleus•Irregular, s-shaped nuclei •Diameter is 8 to 10 microns•>1% of circulating WBCs•Involved in inflammatory and allergy reactions |
| Basophils Leave capillaries and... | enter connective tissue as mast cells |
| Basophils release... | heparin, histamine & serotonin–heighten the inflammatory response and account for hypersensitivity (allergic) reaction |
| Eosinophils (Granulocyte) | Nucleus with 2 or 3 lobes connected by thin strand•Diameter 10-12microns•2-4% of circulating WBCs•Leave capillaries to enter tissue fluid• |
| Eosinophils release... | histaminase –slows down inflammation caused by basophils•Attack parasitic worms•Phagocytize antibody-antigen complexes |
| Lymphocyte (Agranulocyte) | Dark, oval to round nucleus•Cytoplasm sky blue in color–amount varies from rim of blue to normal amount•Small cells 6 - 9 microns in diameter•Large cells 10 - 14 microns in diameter–increase in number during viral infections•20 to 25% of circulating WBCs |
| Lymphocyte functional cells | B cells, T cells, natural killer cells |
| B cells | destroy bacteria and their toxins–turn into plasma cells that produces antibodies |
| T cells | attack viruses, fungi, transplanted organs, cancer cells & some bacteria |
| Natural killer cells | attack many different microbes & some tumor cells–destroy foreign invaders by direct attack |
| Monocyte (Agranulocyte) | Nucleus is kidney/horseshoe shaped•Largest WBC in circulating blood–does't remain in blood long before emigrating–differentiate into fixed&wandering macrophages•Diameter12 -20 microns•3-8% of circulating WBCs |
| Monocyte function | •Destroy microbes and clean up dead tissue following an infection•Take longer to get to site of infection, but arrive in larger numbers |
| Granular leukocytes | Neutrophils, eosinophils, basophils |
| Agranular leukocytes | Lymphocytes (T cells, B cells, natural killer cells), monocyte |
| Complete Blood Count (CBC) | Screens for anemia and infection•Total RBC, WBC & platelet counts; differential WBC; hematocrit and hemoglobin measurements |
| Normal hemoglobin range | Infants have 14 to 20 g/100mL of blood–Adult females have 12 to 16 g/100mL of blood–Adult males have 13.5 to 18g/100mL of blood |
| Differential WBC Count | Detection of changes in numbers of circulating WBCs (percentages of each type)–indicates infection, poisoning, leukemia, chemotherapy, parasites or allergy reaction |
| Normal WBC count for neutrophils | 60-70% (up if bacterial infection) |
| Normal WBC count for lymphocytes | 20-25% (up if viral infection) |
| Normal WBC count for monocytes | 3-8 % (up if fungal/viral infection) |
| Normal WBC count for eosinophil | 2-4 % (up if parasite or allergy reaction) |
| Normal WBC count for basophil | <1% (up if allergy reaction or hypothyroid) |
| Platelets | Help stop blood loss from damaged vessels by forming platelet plug. –Their granules contain chemicals that promote clotting.•Megakaryoblasts transform into megakaryocytes which fragment.•Each fragment, enclosed by piece of cell membrane, is a thrombocyte |
| Stimulates myeloid stem cells to produce platelets. | Thrombopoietin (TPO) |
| Myeloid stem cells develop into ____ that develop into ______ | megakaryocyte-colony-forming cells; megakaryoblasts |
| Platelet (Thrombocyte) Anatomy | Disc-shaped, 2 - 4 micron cell fragment with no nucleus |
| Normal platelet count | 150,000-400,000 per drop of blood |
| Normal RBC count | 5 million |
| Normal WBC count | 5-10,000 |
| Platelets form in bone marrow by the following steps: | myeloid stem cells → megakaryocyte-colony forming cells → megakaryoblast →megakaryocytes (whose cell fragments form platelets) |
| Platelets life span | Short life span (5 to 9 days in bloodstream)–formed in bone marrow–few days in circulating blood–aged ones removed by fixed macrophages in liver and spleen |
| Clotting | Stoppage of bleeding in a quick & localized fashion when blood vessels are damaged•Prevents hemorrhage (loss of a large amount of blood) |
| Methods utilized in clotting | vascular spasm–platelet plug formation–blood clotting (coagulation = formation of fibrin threads) |
| A clot is... | a gel consisting of a network of insoluble protein fibers (fibrin) in which formed elements of blood are trapped. gel separates into liquid (serum) and a clot of insoluble fibers (fibrin) in which the cells are trapped |
| The chemicals involved in clotting are known as | coagulation (clotting) factors; most are in blood plasma, some are released by platelets, and one is released from damaged tissue cells |
| Blood clotting involves a cascade of reactions that may be divided into three stages: | formation of prothrombinase (prothrombin activator), conversion of prothrombin into thrombin, and conversion of soluble fibrinogen into insoluble fibrin |
| The clotting cascade can be initiated by either | the extrinsic pathway or the intrinsic pathway |
| Normal coagulation requires | vitamin K and also involves clot retraction (tightening of the clot) and fibrinolysis (dissolution of the clot). |
| The fibrinolytic system | dissolves small, inappropriate clots and clots at a site of damage once the damage is repaired. |
| Plasmin (fibrinolysin) can dissolve a clot by | digesting fibrin threads and inactivating substances such as fibrinogen, prothrombin, and factors V, VIII, and XII. |
| vascular Spasm | Damage to blood vessel stimulates pain receptors•Reflex contraction of smooth muscle of small blood vessels•Can reduce blood loss for several hours until other mechanisms can take over•Only for small blood vessel or arteriole |
| Granules needed for platelet plug formation | alpha granules, dense granules |
| Chemicals stored in alpha granules | •clotting factors •platelet-derived growth factor–cause proliferation of vascular endothelial cells, smooth muscle & fibroblasts to repair damaged vessels |
| Chemicals stored in dense granules | •ADP, ATP, Ca+2, serotonin, fibrin-stabilizing factor, & enzymes that produce thromboxane A2 |
| Steps in platelet plug process | (1) platelet adhesion (2) platelet release reaction (3) platelet aggregation |
| Platelet Adhesion (plug) | Platelets stick to exposed collagen underlying damaged endothelial cells in vessel wall |
| Platelet Release Reaction (plug) | Platelets activated by adhesion•Extend projections to make contact with each other •Release thromboxane A2 & ADP activating other platelets•Serotonin & thromboxane A2 are vasoconstrictors decreasing blood flow through the injured vessel |
| Platelet Aggregation (plug) | Activated platelets stick together and activate new platelets to form a mass called a platelet plug•Plug reinforced by fibrin threads formed during clotting process |
| Clot formation | Ca+2 needed for clot formation•Clotting is a cascade of reactions which each clotting factor activates next in fixed sequence resulting in formation of fibrin threads |
| When clotting in unbroken vessel called... | thrombosis |
| prothrombinase & Ca+2 convert | prothrombin into thrombin |
| thrombin converts | fibrinogen into fibrin threads |
| Overview of clotting cascade | Prothrombinase is formed by either the intrinsic or extrinsic pathway•Final common pathway produces fibrin threads |
| Extrinsic Pathway | Damaged tissues leak tissue factor (thromboplastin) into bloodstream•Prothrombinase forms in seconds•In the presence of Ca+2, clotting factor X combines with V to form prothrombinase |
| Intrinsic Pathway | Activation occurs–endothelium is damaged & platelets come in contact with collagen of blood vessel wall–platelets damaged & release phospholipids•Requires several minutes for reaction to occur•Substances involved: Ca+2 and clotting factors XII, X and V |
| Prothrombinase and Ca+2 – | catalyze the conversion of prothrombin to thrombin |
| Thrombin in the presence of Ca+2 | converts soluble fibrinogen to insoluble fibrin threads–activates fibrin stabilizing factor XIII –positive feedback effects of thrombin•accelerates formation of prothrombinase•activates platelets to release phospholipids |
| Clot Retraction & Blood Vessel Repair | Clot plugs ruptured area of blood vessel•Platelets pull on fibrin threads causing clot retraction •Edges of damaged vessel are pulled together•Once edges of damaged vessel are pulled together, the repair process begins.(Sewing together a tear in a shirt) |
| Role of Vitamin K in Clotting | Normal clotting requires vitamin K(fat soluble vitamin absorbed if lipids are present) absorption slowed if bile release is insufficient•Required for synthesis of 4 clotting factors by hepatocytes•Produced by bacteria in large intestine |
| fibrinolysis | dissolution of a clot |
| Anticoagulants present in blood & produced by | mast cells |
| Thrombosis– | clot (thrombus) forming in an unbroken blood vessel–may dissolve spontaneously or dislodge & travel |
| Embolus – | clot, air bubble or fat from broken bone in the blood |
| Coagulation Time | Refers to how long it takes blood to clot.•Thrombosis occurs if blood clots to easily•Hemorrhage occurs if blood takes too long to clot |
| Prothrombin time (PT)– | This test is used to evaluate the adequacy of the extrinsic system |
| Partial Thromboplastin Time (PTT)– | This test is used to evaluate the intrinsic coagulation system |
| Anticoagulants | Heparin–warfarin (Coumadin)(antagonist to vitamin K so blocks synthesis of clotting factors)–stored blood in blood banks treated with citrate phosphate dextrose (CPD) that removes Ca+2 |
| Thrombolytic agents are | injected to dissolve clots–directly or indirectly activate plasminogen–streptokinase or tissue plasminogen activator (t-PA) |
| At low doses aspirin | inhibits vasoconstriction and platelet aggregation thereby reducing the chance of thrombus formation. |
| In the ABO system, | agglutinogens (antigens) A and B determine blood types. Plasma contains agglutinins (antibodies), designated as a and b, that react with agglutinogens that are foreign to the individual. |
| Blood Groups and Blood Types | RBC surfaces are marked by genetically determined glycoproteins & glycolipids –agglutinogens or isoantigens–distinguishes at least 24 different blood groups •ABO, Rh, Lewis, Kell, Kidd and Duffy systems |
Created by:
Devtemrys
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