2Blood Functions 1. Transports Dissolved gasses Nutrients Waste products to lungs and kidneysEnzymesHormones from endocrine organs2. RegulatespHElectrolyte concentration of body fluidsBody temperature3. Restricts fluid loss4. Defends pathogens and toxins
6Overview of Blood Circulation Blood leaves the heart via arteries that branch repeatedly until they become capillaries• Oxygen (O2) and nutrients diffuse across capillary walls and enter tissues• Carbon dioxide (CO2) and wastes move from tissues into the blood• Oxygen-deficient blood leaves the capillaries and flows in veins to the heart• This blood flows to the lungs where it releases CO2 and picks up O2• The oxygen-rich blood returns to the heart
7Blood Physical Characteristics and Volume Sticky, opaque fluid with a metallic taste• Color varies from scarlet (oxygen-rich) to dark red (oxygen-poor)• pH of blood is 7.35–7.45• Temperature is 38C, slightly higher than “normal” body temperature• Blood accounts for approximately 8% of body weight• Average volume of blood is 5–6 L for males, and 4–5 L for females
8Plasma Plasma accounts for 55 % of the volume of whole blood. 92% of plasma is water, the rest consists of electrolytes and dissolved organic compounds.Blood plasma contains over 100 solutes, including:• Proteins – albumin, globulins, clotting proteins, etc…• Non-protein nitrogenous substances – lactic acid, urea, creatinine• Organic nutrients – glucose, carbohydrates, amino acids• Electrolytes – sodium (Na+), potassium (K+), calcium (Ca++), chloride (Cl-), bicarbonate (HCO3-)• Respiratory gases – oxygen and carbon dioxide
9Plasma Proteins Albumin 1. Contributes to the osmotic pressure of the blood2. Provides a transport mechanism for specific insoluble or valuable materials in the blood.Globular proteinsBinding and transporting hormones, lipids (lipoproteins), and metal ions.The immunoglobulins (antibodies) are proteins that attack foreign proteins and pathogens.Fibrinogen molecules aggregate to form large insoluble strands of fibrin that establish the basis for a blood clot.
10Erythrocytes Biconcave discs RBCs have no nuclei or organelles (anucleate) allow for a huge surface area to volume ratioHematocrit – % of RBCs out of the total blood volume. (Ave) 46 adult men & 42 adult women.There are roughly 5 million RBCs in each microliter of bloodErythrocytes are unable to perform normal maintenance operations and usually degenerate after about 120 days in the circulation.
12HemoglobinHemoglobin (Hgb), a globular protein formed from four subunits.Heme molecules bind to oxygen when plasma concentrations are high; the oxygen is released when plasma concentrations decline.Carbon dioxide molecules can be bound to the globin portion of the hemoglobin molecule.
14Hemoglobin Composed of: • The protein globin, made up of two alpha and two beta chains, each bound to a heme group• Each heme group bears an atom of iron, which can bind one to oxygen molecule• Each hemoglobin molecule can transport four molecules of oxygenOxyhemoglobin – hemoglobin bound to oxygen• Oxygen loading takes place in the lungsDeoxyhemoglobin- hemoglobin after oxygen diffuses into tissues (reduced Hgb)Carboxyhemoglobin – hemoglobin bound to carbon dioxide• Carbon dioxide loading takes place in the tissues• The fetus forms HbF, which has a higher affinity for oxygen than adult hemoglobin
15What happens to old RBC’S? Damaged or expired red blood cells are recycled by phagocytes.Proteins are disassembled into amino acidsIron gets bound to transferrin for transport to the bone marrow and liverHeme units are not recycled, but removed from the circulation by the liver
16Fate and Destruction of Erythrocytes The life span of an erythrocyte is 100–120 daysDying erythrocytes are engulfed by macrophagesHeme & globin are separated and the iron is salvaged for reuseFate of HemoglobinHeme is degraded to a yellow pigment called bilirubinThe liver secretes bilirubin into the intestines as bileThe intestines metabolize it into urobilinogenThis degraded pigment leaves the body in feces, in a pigment called stercobilin or as urobilinogen in urineGlobin is metabolized into amino acids and is released into the circulation
18Blood TypesAgglutinogens A, B, and D (Rh) on the exposed surfaces of the red blood cells determine an individual's blood type.Anti-Rh agglutinins are only synthesized after an Rh-negative individual becomes sensitized to the Rh agglutinogen. (During pregnancy)Testing for compatibility involves the determination of blood type and a cross-match test.Standard blood typing detects the A, B, and D (Rh) agglutinogens. The most common blood type used for transfusion is O-negative (universal donor – NO ANTIGENS). AB-positive (Universal recipient – NO ANTIBODIES)
22Hemolytic Disease of the Newborn (Erythroblastosis fetalis) Rh+ antibodies of a sensitized Rh– mother cross the placenta and attack and destroy the RBCs of an Rh+ babyRh– mother become sensitized when Rh+ blood (from a previous pregnancy of an Rh+ baby or a Rh+ transfusion) causes her body to synthesis Rh+ antibodiesThe drug RhoGAM can prevent the Rh– mother from becoming sensitized
23Production of Blood Cells Hematopoiesis – blood cell formationHematopoiesis occurs in the red bone marrow of the:- Axial skeleton and girdles- Epiphyses of the humerus and femurHemocytoblasts give rise to all formed elementsCirculating stem cells give rise to embryonic blood cells which migrate into the liver, spleen, thymus, and bone marrow.
25ErythropoiesisOccurs within red marrow of the sternum, vertebrae, skull, scapulae, pelvis, and proximal limb bones.Red blood cell formation increases under erythropoietin stimulation. This hormone is released from the kidneys when they are not receiving adequate supplies of oxygen.Erythropoiesis is hormonally controlled and depends on adequate supplies of iron, amino acids, and B vitaminsReticulocytes (immature RBC’s) usually account for 0.8 percent of circulating red blood cells.
27ErythropoietinErythropoietin (EPO) release by the kidneys is triggered by: • Hypoxia due to decreased RBCs • Decreased oxygen availability • Increased tissue demand for oxygen Erythropoiesis increases the: • RBC count in circulating blood • Oxygen carrying ability of the blood increases
29Erythropoiesis requirement Proteins, lipids, and carbohydratesIron, vitamin B12, and folic acidThe body stores iron in Hgb (65%), the liver, spleen, and bone marrowIntracellular iron is stored in protein-iron complexes such as ferritin and hemosiderinCirculating iron is loosely bound to the transport protein transferrin
30Erythrocyte pathophysiology Anemia – blood has abnormally low oxygen-carrying capacity• Blood oxygen levels cannot support normal metabolism• Signs/symptoms include fatigue, paleness, shortness of breath, increased heartrate, low blood pressure, and chills
31Anemia: Insufficient Erythrocytes Hemorrhagic anemia– result of acute or chronic loss of blood (e.g.Trauma & Menstruation)Hemolytic anemia– prematurely ruptured erythrocytesAplastic anemia– destruction or inhibition of red bone marrowSickle cell anemia
34Anemia: Decreased Hemoglobin Content Iron-deficiency anemia results from:A secondary result of hemorrhagic anemiaInadequate intake of iron-containing foodsImpaired iron absorptionPernicious anemia results from:Deficiency of vitamin B12Often caused by lack of intrinsic factor needed for absorption of B12
36Anemia: Abnormal Hemoglobin Thalassemias – absent or faulty globin chain in hemoglobin• Erythrocytes are thin, delicate, & deficient in hemoglobinSickle-cell anemia – results from a defective gene coding for an abnormal hemoglobin called hemoglobin S (HbS)
39Polycythemia Excess RBCs that increase blood viscosity Blood doping in athletics
40LeukocytesWhite blood cells are components of the immune system that defends the body against pathogens, toxins, wastes, and abnormal or damaged cells and tissues.There are 6,000-9,000 white blood cells in each microliter of whole blood
42Leukocytes Normal response to bacterial or viral invasion Move through tissue spacesGranular leukocytes include neutrophils, eosinophils , and basophils.Neutrophils are abundant, highly mobile phagocytes.Eosinophils are attracted to foreign compounds coated with antibodies.Basophils migrate into damaged tissues and release histamine, aiding in the inflammation response.Monocytes migrating into peripheral tissues become free macrophages.Lymphocytes, cells of the lymphatic system, include T cells and B cells. T cells migrate to peripheral tissues and attack foreign or abnormal cells; B cells produce antibodies.
48Neutrophils (Polymorphonuclear) 60-70% of WBC’sNeutrophils have two types of granules that:• Take up both acidic and basic dyes• Give the cytoplasm a lilac color• Contain peroxidases, hydrolytic enzymes, and defensins (antibiotic-like proteins)Neutrophils are our body’s bacterial slayersLifespan : 1 day in blood; 1-2 days in tissue
49Eosinophils 1-4% of WBC’s Have red-staining, bi-lobed nuclei connected via a broad band of nuclear materialLead the body’s counterattack against parasitic wormsLessen the severity of allergies by phagocytizing immune complexesLifespan: 1 day in blood; weeks in tissue
50Basophils0.5-1% of WBC’sHave large, purplish-black (basophilic) granules that contain histamineHistamine – inflammatory chemical that acts as a vasodilator & attracts other WBCsLifespan: 1 day in blood; hours in tissue
52Lymphocytes 20-25% of WBC’s Have large, dark-purple, circular nuclei with a thin rim of blue cytoplasmFound mostly enmeshed in lymphoid tissue (some circulate in the blood)There are two types of lymphocytes: T cells and B cellsT cells function in the immune responseB cells give rise to plasma cells, which produce antibodiesLifespan: Years
53Monocytes 3-8% of WBC’s They are the largest leukocytes They have abundant pale-blue cytoplasmsThey have purple staining, U- or kidney-shaped nucleiThey leave the circulation, enter tissue, and differentiate into macrophagesLifespan: Days in blood; years in tissue
54Leukocyte pathophysiology Leukemia refer to cancerous conditions involving white blood cellsImmature white blood cells are found in the bloodstream in all leukemiasBone marrow becomes totally occupied with cancerous leukocytesThe white blood cells produced, though numerous, are not functionalDeath is caused by internal hemorrhage and overwhelming infectionsAcute leukemia involves blast-type cells and primarily affects childrenChronic leukemia is more prevalent in older people
55Leukemia Common symptoms of leukemia: Anemia Fever Weakness and fatigueFrequent infectionsLoss of appetite and/or weightSwollen or tender lymph nodes, liver, or spleenEasy bleeding or bruisingTiny red spots (called petechiae) under the skinSwollen or bleeding gumsSweating, especially at nightBone or joint pain.
56Thrombocytes Platelets Megakaryocytes in the bone marrow release packets of cytoplasm, called platelets, into the circulating blood. There are 150, ,000 platelets in each microliter of whole blood.Platelet granules contain serotonin, Ca2+, enzymes, ADP, and platelet-derived growth factor (PDGF)Platelets function in the clotting mechanism by forming a temporary plug that helps seal breaks in blood vessels
60Blood clottingThe coagulation process requires calcium ions, and Vitamin K must be available for the synthesis of five of the clotting factors.
61Hemostasis Pathophysiology Thromboembolytic DisordersThrombus – a clot that develops and persist in an unbroken blood vesselEmbolus – a thrombus freely floating in the blood streamThrombocytopenia – condition where the number of circulating platelets is deficientHemophilias – hereditary bleeding disorders caused by lack of clotting factors
63HemophiliaHemophilia A – most common type (83% of all cases) due to a deficiency of factor VIII• Hemophilia B – results from a deficiency of factor IX• Hemophilia C – mild type, caused by a deficiency of factor XI• Symptoms include prolonged bleeding and painful and disabled joints• Treatment is with blood transfusions and the injection of missing factors
66Prevention of undesirable clots Substances used to prevent undesirable clots include: • Aspirin • Heparin • Warfarin (Coumadin) • Flavonoids – substances found in tea, red wine, and grape juice that have natural anticoagulant activity