1. Chapters 12 Blood & the Cardiovascular System Human Anatomy & Physiology P. Wilson1

2. 2 Blue Boxes for Chapter 12  Pg 304: Cyanosis & hypoxia  Pg 307: newborn jaundice & bili lights  Pg 317: mismatched blood transfusion  Pg 317: (paperman) ABO blood types  Pg 319: (paperman) Rh blood type

3. II. 12.1 Introduction The functions of the blood are: to transport nutrients, oxygen, wastes, & hormones to help maintain the stability of interstitial fluid (the fluid between cells) to distribute heat to transport substances between body cells & the external environment (helping to maintain homeostasis) Human Anatomy & Physiology P. Wilson3

4. III. 12.2 A. Blood & Blood Cells 1.The solid elements of blood (aka “formed” elements)are: red blood cells (RBCs) white blood cells (WBCs) platelets 2.The blood volume of an average sized male is 5 liters. males have more blood than females (1.500 gallons to 0.875 gallons) 3.Plasma (a clear, straw-colored liquid) makes up about 55% of blood. 4. Plasma consists of water, amino acids, carbohydrates, lipids, vitamins, hormones, electrolytes, & cellular wastes Human Anatomy & Physiology P. Wilson4

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6. III. 12.2 B. Blood & Blood Cells Red Blood Cells 1.The shape of RBCs is a biconcave disc 2.The shape is an adaptation for transporting gases – it increases the surface area through which gases can diffuse. Human Anatomy & Physiology P. Wilson6

7. III. 12.2 B. Blood & Blood Cells Red Blood Cells 3.The color of an RBC is due to the presence of hemoglobin (makes up about 1/3 of the cell’s volume). Red blood cells are bright red when carrying oxygen (oxygen-rich) because that is the color of oxyhemoglobin; deoxyhemoglobin is formed when the oxygen has been released (oxygen-poor blood) and it is a darker red color. Human Anatomy & Physiology P. Wilson7

8. III. 12.2 B. Blood & Blood Cells Red Blood Cells 4.Mature RBCs lack a nucleus. the main function of RBCs is to carry oxygen so once the RBC has completed development the nucleus is extruded, providing more space for hemoglobin Human Anatomy & Physiology P. Wilson8 The average life span of a RBC is 120 days. The combined surface area of all the RBCs in the human body is roughly 200 times as great as the body’s exterior surface!

9. III. 12.2 C. Blood & Blood Cells Red Blood Cell Counts 1.The typical red blood cell count is 4,600,000-6,2000,000 cells per mm 3 for males and 4,500,000-5,100,000 cells per mm 3 for females. 2.When prolonged exposure to low oxygen levels are experienced, the kidneys & liver release the hormone erythropoietin which stimulates hematopoiesis (production of RBCs) Human Anatomy & Physiology P. Wilson9

10. III. 12.2 C. Blood & Blood Cells Red Blood Cell Counts 3.Dietary factors that influence the production of RBCs are folic acid & vitamin B – essential for DNA synthesis; new blood cells are constantly being produced to replace worn out & damaged cells – DNA is necessary for the cell production iron – essential for the production of hemoglobin Human Anatomy & Physiology P. Wilson10

11. III. 12.2 C. Blood & Blood Cells Red Blood Cell Counts 4.RBCs are produced in the early embryo & fetus, RBCs are produced in the yolk sac in late fetal stages, RBCs are produced in the liver & spleen after birth, RBCs are produced in red bone marrow Human Anatomy & Physiology P. Wilson11

12. III. 12.2 C. Blood & Blood Cells Red Blood Cell Counts 5.RBC production is controlled by negative feedback using the hormone erythropoietin. The kidneys & liver release erythropoietin in response to prolonged oxygen deficiency. 1)Oxygen deficiency is detected 2)Kidneys & liver release erythropoietin which travels to target cells in red bone marrow 3)Erythropoiesis begins & within a few days new RBCs appear in circulating blood 4)Oxygen levels increase; when “normal” set point is reached, erythropoietin release decreases & the rate of RBC production returns to normal Human Anatomy & Physiology P. Wilson12

13. III. 12.2 C. Blood & Blood Cells Red Blood Cell Counts 6.In individuals affected with sickle-cell anemia, a single DNA base change causes an incorrect amino acid to be added to the globin protein chain. The defective hemoglobin crystallizes in a low oxygen environment, causing the RBCs to bend into a sickle shape. The sickle-shaped cells cause circulation blockage in small blood vessels causing joint pain and damaging organs Human Anatomy & Physiology P. Wilson13

14. III. 12.2 C. Blood & Blood Cells Human Anatomy & Physiology P. Wilson14

15. III. 12.2 D. Destruction of RBCs 1.As RBCs age they become less elastic, less flexible, & more fragile and are damaged as they pass through capillaries. 2.Damaged RBCs are phagocytized (destroyed) by macrophages located in the spleen and liver. The hemoglobin breaks down into heme (the iron-containing portion) and globin (the protein potion). The heme is further decomposed into biliverdin (a green pigment) which is eventually broken down into bilirubin (an orange pigment). Both biliverdin & bilirubin are excreted in bile. The iron from hemoglobin may be transported to the red bone marrow tissue responsible for hematopoiesis to be reused in the production of RBCs Human Anatomy & Physiology P. Wilson15

16. III. 12.2 E. Types of WBCs Human Anatomy & Physiology P. Wilson16

17. Types of White Blood Cells aka Leukocytes White blood CellDescription% of TotalFunction GranulocytesHave granular cytoplasm (3 types). About twice the size of RBCs Develop in red bone marrow. Life span about 12 hours Neutrophillobed nucleus (2-5 lobes)54-62% of WBC Most mobile & active of the phagocytes; ingest bacteria Eosinophilbi-lobed nucleus1-3% of WBCs Weakly phagocytic; attracted to & lethal to certain parasites; helps control inflammation & allergic reactions BasophilSimilar appearance to eosinophils <1% of WBCs Releases heparin (prevents clots) and histamine (increases blood flow to injuries); histamines play major roles in allergic reactions Human Anatomy & Physiology P. Wilson17 Normal WBC count is 5000 – 10000 per mm 3 Functions: destroy pathogenic microorganisms & parasites, and remove worn out cells

18. Types of White Blood Cells aka Leukocytes White blood CellDescription% of TotalFunction AgranulocytesCytoplasm lacks granules MonocyteLargest WBC (2-3x size of RBC) Nuclei vary in shape 3-9% of WBC Aka macrophage; phagocytize large particles (ex: foreign proteins) Life span: several weeks to months LymphocyteSlightly larger than RBC; large, round nucleus & small rim of cytoplasm 25-33% of WBCs Produce antibodies that attack specific foreign substances. Life span: years Human Anatomy & Physiology P. Wilson18

19. III. 12.2 F. WBC Counts 1.Normal WBC count is 5000 – 10000 per mm 3. 2.Causes of WBC count changes: Leukocytosis (> 10000 per mm 3 ) indicates an acute infection such as appendicitis Leukopenia (< 5000 per mm 3 ) may indicate measles, mumps, typhoid fever, influenza, AIDS, or poliomyelitis. Human Anatomy & Physiology P. Wilson19

20. III. 12.2 F. WBC Counts 3.A differential WBC count list the percentages of the various types of leukocytes. The relative proportions of WBCs help with diagnoses. Ex: increase in neutrophils indicates a bacterial infection, while an increase in eosinophils indicates the presence of a parasite or an allergen. Human Anatomy & Physiology P. Wilson20

21. III. 12.2 G. Platelets Platelets (aka thrombocytes) arise from large cells in the marrow called megakaryocytes.. The megakaryocytes shatter into small fragments (platelets) that contain cytoplasm but no nucleus. Megakaryocytes & platelets increase in numbers in response to the hormone thrombopoietin. Platelets move like an amoeba, have a life span of about 10 days, and play a vital role in blood clotting. Human Anatomy & Physiology P. Wilson21

22. IV. 12.3 Blood Plasma ProteinDescription% of TotalFunction Albumins Smallest of the plasma proteins Synthesized in the liver 60%Helps maintain osmotic pressure Globulins alpha & beta are synthesized in the liver gamma- synthesized in lymphatic tissue 36% alpha & beta: transport of lipids & fat-soluble vitamins gamma- these are antibodies Fibrinogen Largest of the plasma proteins synthesized in lymphatic tissue 4%Blood coagulation Human Anatomy & Physiology P. Wilson22 A. Plasma Proteins

23. IV. 12.3 B. Blood Plasma: Nutrients & Gases Human Anatomy & Physiology P. Wilson23 1.Oxygen, nitrogen, carbon dioxide are the gases found on blood plasma. 2.The nutrients found in blood plasma are amino acids, simple sugars, nucleotides, & lipids. 3.Non-protein nitrogenous substances found in plasma are amino acids, urea, & uric acid (these are products of protein & nucleic acid digestion) Levels of these substances in the plasma can be used as a measure of kidney & liver function.

24. IV. 12.3 C. Blood Plasma: Electrolytes Human Anatomy & Physiology P. Wilson24 1.Sodium, potassium, calcium, magnesium, chloride, bicarbonate, phosphate, & sulfate ions are the electrolytes found in blood plasma. Sodium and chloride ions are the most abundant ions in plasma 2.The function of electrolytes is to regulate the acid-base balance and they have role in nerve and muscle function.

25. V. 12.4 Hemostasis Human Anatomy & Physiology P. Wilson25 A.The mechanisms of hemostasis, or stoppage of bleeding, are: vasospasm – cutting a blood vessel causes the muscle in its walls to contract in a reflex, or engage in vasospasm. This reflex lasts only a few minutes, but it lasts long enough to initiate the 2 nd & 3 rd steps of hemostasis. platelet plug formation - platelets stick to the exposed edges of damaged blood vessels (and to each other), forming a net with spiny processes protruding from their membranes; a platelet plug is most effective on a small vessel. blood coagulation - is the most effective means of hemostasis & is a very complex process using clotting factors

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27. V. 12.4 Hemostasis Human Anatomy & Physiology P. Wilson27 C.Major events in the blood-clotting mechanism: in the presence of calcium, prothrombin converts to thrombin thrombin catalyzes the conversion of fibrinogen to long strands of fibrin fibrin sticks to exposed surfaces of blood vessels forming a mesh to trap other blood elements (WBCs, RBCs, & platelets). the mass formed is a blood clot.

28. V. 12.4 Hemostasis Human Anatomy & Physiology P. Wilson28 D.Normal blood flow prevents the concentration of thrombin from too low to cause clotting. When blood flow is diminished or when blood pools, the concentration of thrombin increases and can lead to a blood clot or a thrombus. E.Thrombi & emboli can be formed A thrombus is a blood clot abnormally formed in a blood vessel that is not moving. An embolus is a fragment of a clot that breads off & is carried away by blood flow.

29. V. 12.4 Hemostasis Human Anatomy & Physiology P. Wilson29 E.Thrombus vs embolus: A thrombus is a blood clot abnormally formed in a blood vessel that is not moving. An embolus is a fragment of a clot that breads off & is carried away by blood flow. Thrombi or emboli can be formed under any of the following circumstances: atrial fibrillation (the most common type of cardiac arrhythmia – rate or rhythm of heartbeat) incompetent venous valves immobility the formation of plaques in atherosclerosis

30. VI. 12.5 Blood Groups & Transfusions Human Anatomy & Physiology P. Wilson30 A.Agglutinogens & Agglutinins 1.Antigens (Agglutinogens) are molecules on the surface of RBCs that determine the ABO blood type. Antibodies (agglutinins) are molecules found in the plasma that react with antigens, and if incompatible, will “clump” together (or agglutinate).  Note: ABO antibodies form in an infants blood within 2 to 8 months following birth. These antibodies are specific for blood type. Whenever A antigen is absent from the body anti-A antibodies form; when B antigen is absent, anti- B antibodies form. 2.Agglutinogens are on the surface of RBCs; agglutinins on in the plasma.

31. VI. 12.5 Blood Groups- Genetics Human Anatomy & Physiology P. Wilson31 Basic ABO blood group has 3 alleles (versions of the gene): I A, I B, and i alleles. I A and I B are co-dominant and i is recessive. Type A blood can be homozygous (I A I A) or heterozygous (I A i) Type B blood can be homozygous (I B I B) or heterozygous (I B i) Type AB blood is I A I B Type O blood is ii Rh blood group has 2 alleles: Rh+ and Rh- Rh+ type blood can be homozygous (Rh+ Rh+) or heterozygous (Rh+ Rh-) Rh- type blood is Rh- Rh-

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33. VI. 12.5 Blood Groups & Transfusions Human Anatomy & Physiology P. Wilson33 B.ABO Blood Group 1.The presence, or lack, of specific antigens determine blood type: A antigen only – type A blood B antigen only – type B blood both A & B antigens - type AB blood Neither A nor B antigen – type O blood 2.If incompatible antigens and antibodies are mixed “clumping” (technical term is agglutination) and transfusion reactions can occur (may have serious & life threatening consequences – see blue box on p. 317)

34. VI. 12.5 Blood Groups & Transfusions Human Anatomy & Physiology P. Wilson34 C.Rh Blood Group 1.There are several Rh antigens that determine if a blood type is Rh+ or Rh-. The most important is antigen D. 2.Anti-Rh antibodies do not form spontaneously. Anti-Rh antibodies form only in Rh- individuals in response to stimulation (through exposure to Rh antigen).

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37. VI. 12.5 Blood Groups & Transfusions Human Anatomy & Physiology P. Wilson37 3.Rh Blood Group Erythoblastosis fetalis occurs when a woman who has already developed anti-Rh antibodies (due to a previous exposure) becomes pregnant with an Rh+ fetus. The woman’s antibodies will cross the placental membrane & destroy the fetal red blood cells. This condition is rare today because physicians carefully track Rh status of pregnant females. A Rh- female who might carry a Rh+ fetus is given a RhoGAM shot. Antibodies in the injection bind to & shield any Rh+ fetal cells.