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The Cardiovascular System: Blood

The Cardiovascular System: Blood. Blood. Primary Functions Brings oxygen and nutrients to the cells. Carries away waste. Distributes heat Helps defend the body against infection Related Combining Forms hem/o, hemat/o. Characteristics.

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The Cardiovascular System: Blood

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  1. The Cardiovascular System: Blood

  2. Blood • Primary Functions • Brings oxygen and nutrients to the cells. • Carries away waste. • Distributes heat • Helps defend the body against infection • Related Combining Forms • hem/o, hemat/o

  3. Characteristics • There are 4-6 L of blood in the human body (depending on body size) • About 55% of the blood is a straw-coloured fluid called plasma • The remaining portion of blood is made up of the “formed elements”: • Erythrocytes • Leukocytes • Thrombocytes

  4. Plasma • Plasma is about 91% water • The rest consists of proteins, nutrients, hormones, and waste products • Proteins include albumin, globulins, fibrinogen, and prothrombin • When the two major clotting proteins (fibrinogen and prothrombin) are removed, the fluid is called serum • Blood gases are dissolved in plasma (ex Oxygen, Carbon Dioxide, Nitrogen)

  5. Formed Elements • Erythrocytes (Red Blood Cells) • Erythr/o means red, -cyte means cell • Carry oxygen to the body tissues • 99% of the cells in blood • Biconcave (increases surface area to intracellular space ratio) • Membrane is very flexible • Do not have nuclei

  6. Formed Elements • Erythrocytes carry a protein called Hemoglobin (Hb) • Hemoglobin molecules contain atoms of iron which attract oxygen when it is plentiful and release it when scarce • Iron gives hemoglobin it’s red colour • Protein is also essential for Hb synthesis

  7. Formed Elements • Life span • RBC’s live for approximately 120 days • At that time they become fragile, and are removed from the bloodstream by macrophages located in the liver, spleen, and bone marrow • When the old cells are destroyed, the iron they contained is released and is carried back to the bone marrow to be used in the synthesis of new hemoglobin (excess is stored in the liver) • The heme part of the Hb molecule cannot be recycled and is converted to the waste product bilirubin by the macrophages • The bilirubin is removed from the blood by the liver, and is excreted into bile

  8. Formed Elements • Leukocytes (White Blood Cells) • Leuk/o means white, -cyte means cell • Protect the body against invaders • Have a nucleus • Can change shape and move out through the vessel walls into the tissues • There are 5 kinds of WBC’s:

  9. Formed Elements • Neutrophils • Formed in red bone marrow • Most common type • Can leave the bloodstream to find, engulf, and swallow germs • phagocytosis(phag/o means to eat)

  10. Formed Elements • Basophils • Assist in the inflammatory response • Responsible for many of the symptoms of allergies

  11. Formed Elements • Eosinophils • Destroy parasitic organisms • Play a role in allergic reactions

  12. Formed Elements • Monocytes • Formed in red bone marrow, lymph nodes, and spleen • Perform phagocytosis - clean up bacteria, dead and dying cells, and other debris • Can differentiate into macrophages

  13. Formed Elements • Lymphocytes • Formed in the red bone marrow, lymph nodes, and spleen • Participate in the immune response – recognizing foreign antigens and creating antibodies

  14. Formed Elements • Thrombocytes • AKA Platelets • Thromb/o means clot • Not actual cells, but are cell fragments • Help to prevent blood loss (hemostasis – watch spelling!) and form clots

  15. Formed Elements • Formed in the bone marrow by the stem cells in a process called hematopoiesis • (-poiesis means production, formation) • All formed elements are derived from the same hematopoietic stem cells • Proteins in the bone marrow and blood influence the stem cells to change size and shape to become specialized

  16. Blood Types • Many different factors that identify blood “types” • 2 Major: • ABO blood group • Rh factor • Both are inherited

  17. Blood Types • ABO Group • Four major groups identified by the presence of antigens on the surface of the cell • Type A – has A antigen, B antibody • Type B – has B antigen, A antibody • Type AB – has both A and B antigen, no antibodies • Type O – has no antigens, both A and B antibodies • The genes for the antigens are inherited in a co-dominant pattern

  18. Blood Types • Each type also natural antibodies circulating in the blood against the antigens not present on the cell surface • These antibodies bind to antigens of a foreign type and cause the cells to clump (agglutinate) and rupture (hemolysis) • Therefore, donated blood must be very carefully cross-matched

  19. Blood Types http://nobelprize.org/medicine/educational/landsteiner/index.html http://www.biology.arizona.edu/human_bio/problem_sets/blood_types/rh_factor.html

  20. Blood Types • Rh Factor • If the Rh factor antigen is present on the RBCs, the blood is said to be Rh positive • If the Rh factor antigen is not present on the RBCs, the blood is said to be Rh negative • People who are Rh negative do not have natural antibodies to the Rh antigen, but the antibodies can develop if exposed to positive blood • Rh positive is the dominant allele (85% of Americans are Rh positive)

  21. Coagulation • AKA Blood Clotting • When injury occurs, platelets clump at the site to create a platelet plug • A cascade of events then occurs which results in prothrombin and fibrinogen working together to form fibers of fibrin which cover the site, and pull the sides of the cut together for healing

  22. Blood Pathology • Leukemia (-emia means blood condition) • Malignancy of the blood forming tissues • Overproduction of immature white blood cells • Very susceptible to infection • Deficiency of other formed elements • Anemia, hemorrhage • May be treated with chemotherapy and bone marrow transplants

  23. Leukemia

  24. Blood Pathology • Anemia • Deficiency of erythrocytes (erythropenia), or insufficient hemoglobin • Often just a sign of another disease • Symptoms can include: • Pallor • Tachycardia • Chest pain • Shortness of breath • Fatigue

  25. Blood Pathology • Aplastic Anemia • Absence of all formed elements of blood • Failure of hematopoiesis • Plast/o means growth or formation • Can be idiopathic, or due to chemical exposure, pregnancy, lupus, etc

  26. Blood Pathology • Hemolytic Anemia • Erythrocytes are destroyed faster than they can be replaced • Can be caused by infection, medication, inheritance, or autoimmune disorders • -lytic means to destroy

  27. Blood Pathology • Iron-deficiency Anemia • Decrease in the number of erythrocytes because there is not enough iron • Due to inadequate intake, malabsorption, pregnancy and lactation, chronic blood loss • Occurs in approx. 20% of women, 50% of pregnant women, and 3% of men

  28. Blood Pathology • Megaloblastic Anemia • Erythrocytes are unusually large • Usually due to a deficiency of folic acid or vitamin B12 • Pernicious Anemia • Autoimmune disorder • Cells are unusually formed due to an inability of the body to absorb vitamin B12

  29. Blood Pathology • Sickle Cell Anemia • Inherited disorder that causes abnormal hemoglobin formation • Cells become crescent shaped • Very fragile – can break apart easily • Function abnormally and cause clots to form • Results in painful “crises” • Inherited as a recessive (people who inherit one dominant and one recessive allele have sickle cell trait)

  30. Blood Pathology • Thalassemia • Inherited condition that results in absent or decreased production of normal hemoglobin • Many different forms, can be mild or severe • One of the more severe forms is known as Cooley’s anemia

  31. Blood Pathology • Dyscrasia • -crasia means blending • Any pathologic condition of the formed elements of the blood • Hemochromatosis • Chromat/o means colour • Genetic disorder • Intestines absorb too much iron • Iron accumulates in the organs and causes damage

  32. Blood Pathology • Septicemia • AKA Blood Poisoning • Presence of bacteria in the blood • May be due to a spreading of another infection • Can be very serious – even fatal • Hyperlipidemia • Elevated plasma concentrations of cholesterol, triglycerides, and lipoproteins • Lipid means fat

  33. Blood Pathology • Polycythemia Vera • When insufficient oxygen arrives at the tissues, increased erythrocyte production is stimulated • Due to genetics or external conditions like increased elevation • Can result in elevated blood pressure, increased viscosity of blood, increased susceptibility to clots

  34. Blood Pathology • Hemophilia • Phil/o means attraction • Caused by hereditary deficiency of one of several clotting factors (ex Factor VIII or IX) • Results in reduced ability to clot and eventual anemia

  35. Blood Pathology • Myelodysplastic Syndrome • In the past was known as preleukemia • Only about 30% of the cases progress • Some of the hematopoietic tissue is dysfunctional leading to a shortage of blood cells • -dysplasia means bad growth or development

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