Chapter 19

1. Chapter 19 The Cardiovascular System: The Blood

2. What is blood? • Blood is a connective tissue composed of a liquid extracellular matrix called plasma. It has cells and cell fragments dissolved in it. • The cardiovascular system is made up of blood, the heart, and blood vessels. Principles of Human Anatomy and Physiology, 11e

3. Functions 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 • Hematology is study of blood and blood disorders Principles of Human Anatomy and Physiology, 11e

4. Physical Characteristics of Blood • Thicker than water and therefore flows more slowly than water • Feels sticky • Temperature of 100.4 degrees F • pH 7.4 (7.35-7.45) • 8 % of total body weight • Blood volume • 5 to 6 liters in average male • 4 to 5 liters in average female Principles of Human Anatomy and Physiology, 11e

5. Techniques of Blood Sampling • Venipuncture • Most common method • sample taken from vein with hypodermic needle & syringe • Finger or heel stick • Used by diabetics to monitor blood sugar • Used to test blood of infants • Arterial stick: used to determine oxygen levels Principles of Human Anatomy and Physiology, 11e

6. COMPONENTS OF BLOOD • Blood consists of 55% plasmaand 45% of cells. • Blood plasma consists of 91.5% water and 8.5% solutes. • Principal solutes include nutrients, enzymes, hormones, respiratory gases, electrolytes, and waste products. Principles of Human Anatomy and Physiology, 11e

7. Blood Cells • Red blood cells, 40% ( erythrocytes ) • White blood cells, 20% ( leukocytes ) • neutrophils, eosinophils, basophils • lymphocytes = T cells, B cells, and natural killer cells • monocytes • Platelets, 30% (special cell fragments) Principles of Human Anatomy and Physiology, 11e

8. Hematocrit • Hematocrit is the percentage of total blood volume occupied by RBCs. • Anemia • not enough RBCs or not enough hemoglobin • Can be due to leukemia, iron deficiency, or B12 deficiency • Vitamins or injections of iron can treat anemia • Polycythemia • too many RBCs (over 65%) • dehydration, blood loss (including menstruation), blood doping in athletes (common in professional cycling to increase O2 supplies to the blood, muscles, and lungs)

9. Formation of Blood Cells • Most blood cells types need to be continually replaced • die within hours, days or weeks • process of blood cells formation is hematopoiesis or hemopoiesis • In the embryo • occurs in yolk sac, liver, spleen, thymus, lymph nodes & red bone marrow • In adults • occurs only in red marrow of flat bones like sternum, ribs, skull & pelvis and ends of long bones Principles of Human Anatomy and Physiology, 11e

10. Red Blood Cells or Erythrocytes • Contain oxygen-carrying protein hemoglobin that gives blood its 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 other organelles Principles of Human Anatomy and Physiology, 11e

11. RBC Life Cycle • RBCs live only 120 days • wear out from bending to fit through capillaries • no repair possible due to lack of organelles • Worn out cells removed by macrophages in spleen & liver Principles of Human Anatomy and Physiology, 11e

12. Erythropoiesis: Production of RBCs • Erythrocyte formation, called erythropoiesis, occurs in adult red bone marrow of certain bones. • It takes 1-2 days for a mature red blood cell to be formed and released into the blood stream. Principles of Human Anatomy and Physiology, 11e

13. Hemoglobin • Each RBC has 280 million hemoglobin molecules • Each one can bind 4 molecules of oxygen (to the iron at the center of the molecule). • Hemoglobin removes CO2 from the blood • Hemoglobin also regulates blood pressure by regulating nitric oxide in the blood Principles of Human Anatomy and Physiology, 11e

14. WHITE BLOOD CELLS • Leukocytes (WBCs) have a nucleus but do not have hemoglobin. • Granular leukocytes include eosinophils, basophils, and neutrophils based on the straining of the granules. • Agranular leukocytes do not have cytoplasmic granules and include the lymphocytes and monocytes. Principles of Human Anatomy and Physiology, 11e

15. WBC Physiology • Less numerous than RBCs • 5000 to 10,000 cells per drop of blood • 1 WBC for every 700 RBC • Leukocytosis is a high white blood cell count • microbes, disease, strenuous exercise, anesthesia, cancer or surgery • Leukopenia is low white blood cell count • radiation, shock or chemotherapy • Only 2% of total WBC population is in circulating blood at any given time • rest is in lymphatic fluid, skin, lungs, lymph nodes & spleen Principles of Human Anatomy and Physiology, 11e

16. Neutrophils (Granulocyte) • The most abundant WBC • 60 to 70% of circulating WBCs • First cells to migrate to the site of bacterial infection or cancer formation. • Also involved in healing injuries • release lysozymes which destroy/digest bacteria • release defensin proteins that act like antibiotics & poke holes in bacterial cell walls destroying them • release strong oxidants (bleach-like, strong chemicals) that destroy bacteria Principles of Human Anatomy and Physiology, 11e

17. Eosinophils (Granulocyte) • 2 to 4% of circulating WBCs • Combat parasites and infections • Fight allergies and asthma Principles of Human Anatomy and Physiology, 11e

18. Basophils (Granulocyte) • Less than 1% of circulating WBCs • Store histamine and can contribute to allergic reactions • Also contain heparin, which prevents blood from clotting too quickly Principles of Human Anatomy and Physiology, 11e

19. Lymphocyte (Agranulocyte) • 20 to 25% of circulating WBCs • The main soldiers in the immune system battles • 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 (NKC) • attack many different microbes & some tumor cells • destroy foreign invaders by direct attack Principles of Human Anatomy and Physiology, 11e

20. Monocyte (Agranulocyte) • 3 to 8% of circulating WBCs • Stored in the spleen • Produce macrophages which attack bacteria • Destroy microbes and clean up dead tissue following an infection Principles of Human Anatomy and Physiology, 11e

21. PLATELETS • Platelets help stop blood loss from damaged vessels by forming a platelet plug. • Their granules also contain chemicals that promote blood clotting. Principles of Human Anatomy and Physiology, 11e

22. Platelet (Thrombocyte) Anatomy • Disc-shaped cell fragment with no nucleus • They are produced in the bone marrow and live 5 to 9 days in the blood stream before being recycled by the spleen and liver. Principles of Human Anatomy and Physiology, 11e

23. Bone Marrow Transplant • Bone marrow transplant replaces diseased marrow with healthy marrow. • Patient’s diseased marrow is destroyed by cancer or disease. • Healthy marrow is supplied by a donor or the patient. It is removed (painfully) by sticking a needle into the hipbone. • Risks to recipient include: • Infection due to decreased WBC • T cells might attack new bone marrow • Must take immunosuppressant drugs for life Principles of Human Anatomy and Physiology, 11e

24. Cord-Blood Transplant • Stem cells are taken from the umbilical cord and frozen • This method offers several advantages over marrow transplant. • Easy to obtain • More abundant • Are not rejected by patient • Don’t transmit infections • Can be stored, frozen, forever Principles of Human Anatomy and Physiology, 11e

25. Hemostasis • Stoppage of bleeding in a quick & localized fashion when blood vessels are damaged • Prevents hemorrhage (loss of a large amount of blood) • Methods utilized • vascular spasm • platelet plug formation • blood clotting Principles of Human Anatomy and Physiology, 11e

26. Vascular Spasm • Damage to blood vessel produces stimulates pain receptors • Small blood vessels are contracted which reduces blood flow to the injury site

27. Platelet Plug Formation • Steps in the process • (1) platelet adhesion (2) platelet release reaction (3) platelet aggregation Principles of Human Anatomy and Physiology, 11e

28. Platelet Adhesion • Platelets stick to exposed collagen underlying damaged cells in vessel wall Principles of Human Anatomy and Physiology, 11e

29. Platelet Release Reaction • Platelets activated by adhesion • Extend projections to make contact with each other • This decreases blood flow to injury site Principles of Human Anatomy and Physiology, 11e

30. Platelet Aggregation • 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 Principles of Human Anatomy and Physiology, 11e

31. Clot Retraction & Blood Vessel Repair • The plug stops the bleeding, then… • Edges of damaged vessel are pulled together • Fibroblasts & endothelial cells repair the blood vessel Principles of Human Anatomy and Physiology, 11e

32. Blood Clotting • Blood drawn from the body thickens into a gel • gel separates into liquid (serum) and a clot of insoluble fibers (fibrin) in which the cells are trapped • If clotting occurs inside the body, it is called athrombosis • Having vitamin K in your diet can help prevent blood clotting Principles of Human Anatomy and Physiology, 11e

33. Blood Groups and Blood Types • RBC surfaces are marked by antigens, which determine blood type Principles of Human Anatomy and Physiology, 11e

34. ABO Blood Groups • Blood types in humans are: • display only antigen A -- blood type A • display only antigen B -- blood type B • display both antigens A & B -- blood type AB • display neither antigen -- blood type O • Type O is the universal donor • Type AB is the universal receiver Principles of Human Anatomy and Physiology, 11e

35. RH blood groups • Antigen was discovered in blood of Rhesus monkey • People with Rh agglutinogens on RBC surface are Rh+. • Most people are Rh + • If an Rh - woman is pregnant and the baby is Rh+, the mother’s body may reject the pregnancy; she must take anti-rejection drugs and be closely monitored. Principles of Human Anatomy and Physiology, 11e

36. DISORDERS: HOMEOSTATIC IMBALANCES • Anemia • Sickle-cell • Hemophilia • Disseminated intravascular clotting • Acute leukemia • chronic leukemia Principles of Human Anatomy and Physiology, 11e

37. Anemia = Not Enough RBCs • Symptoms • oxygen-carrying capacity of blood is reduced • fatigue, cold intolerance & paleness • Types of anemia • iron-deficiency =lack of absorption or loss of iron • pernicious = lack of intrinsic factor for B12 absorption • hemorrhagic = loss of RBCs due to bleeding (ulcer) • hemolytic = defects in cell membranes cause rupture • thalassemia = hereditary deficiency of hemoglobin • aplastic = destruction of bone marrow (radiation/toxins) Principles of Human Anatomy and Physiology, 11e

38. Sickle-cell Anemia • Genetic defect in hemoglobin molecule • RBC is deformed • sickle-shaped cells rupture easily = causing anemia & clots • Found among populations in malaria belt • Mediterranean Europe, sub-Saharan Africa & Asia Principles of Human Anatomy and Physiology, 11e

39. Hemophilia • Inherited deficiency of clotting factors • bleeding spontaneously or after minor trauma • subcutaneous & intramuscular hemorrhaging • nosebleeds, blood in urine, articular bleeding & pain • Treatment is transfusions of fresh plasma or concentrates of the missing clotting factor Principles of Human Anatomy and Physiology, 11e

40. Disseminated Intravascular Clotting • Life threatening paradoxical presence of blood clotting and bleeding at the same time throughout the whole body • Associated with infections, hypoxia, low blood flow rates, trauma, hypotension & hemolysis • Clots cause necrosis leading to multisystem organ failure

41. Leukemia • Acute leukemia • uncontrolled production of immature leukocytes • crowding out of normal red bone marrow cells by production of immature WBC • prevents production of RBC & platelets • Chronic leukemia • accumulation of mature WBC in bloodstream because they do not die Principles of Human Anatomy and Physiology, 11e