1.blood composition & functions. PHYSIOLOGY LECTURE BY Dr. Naqvi. pptx

blood composition & functions

1. Blood Composition & Functions of Blood Lecture by Dr. M. Baqir Raza Naqvi - 1

2. How to define the blood; Blood was defined earlier as a mixture of cellular components suspended in a fluid called plasma . or Blood is composed of formed elements (cells and cell fragments) suspended in a liquid called plasma. I n the plasma, a large number of proteins, nutrients, metabolic wastes , and other molecules being transported between organ systems, are dissolved. - 2

3. Blood Blood is a connective tissue in fluid form. It is considered as the ‘fluid of life’ because it carries oxygen from lungs to all parts of the body and carbon dioxide from all parts of body to the lungs. 3

4. It is known as ‘ fluid of growth’ because it carries nutritive substances from the digestive system and hormones from endocrine gland to all the tissues. - 4

5. The blood is also called the ‘fluid of health’ because it protects the body against the diseases and gets rid of the waste products and unwanted substances by transporting them to the excretory organs like kidneys. 5

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7. „ PROPERTIES OF BLOOD 1. Color Blood is red in color. Arterial blood is scarlet red because it contains more oxygen. V enous blood is purple red because of more carbon dioxide. - 7

8. 2. Volume Average volume of blood in a normal adult is 5 - 5.5 L . In a newborn baby, the volume is 450 ml. It increases during growth and reaches 5 L at the time of puberty. In females, it’s slightly less and is about 4.5 L. It is about 8% of the body weight in a normal young healthy adult, weighing about 70 kg. - 8

9. PH of Blood Blood is slightly alkaline and its pH in normal conditions is 7.4 - 9

10. Viscosity Blood is five times more viscous than water. It is mainly due to red blood cells and plasma proteins. 10

11. The Hematocrit Value (Hct.) The hematocrit is defined as the percentage of blood volume i.e. erythrocytes. Measurement of Hct: It is measured by Centrifugation (for 30 min. at a speed of 3000 rpm) of a sample of blood. Result: Erythrocytes are forced to the bottom of the centrifuge tube, the plasma remains on top, and the leukocytes & platelets form a very thin layer between them called the buffy coat . 11

12. Range of Hct: The hematocrit is normally about 45% in men and 42% in women. Hct. is also called packed cell volume (PCV). Example: The volume of blood in a 70 kg (154 lb ) person is approximately 5.5 L. If we take the hematocrit to be 45%, then; Erythrocyte volume = 0.45 × 5.5 L = 2.5 L - 12

13. Blood contains the blood cells which are called formed elements. The liquid portion known as plasma. Composition of Blood 13

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16. Plasma Liquid part of blood Pale yellow made up of, 92% water Proteins Mineral ions Glucose and nutrients Hormones CO 2 16

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18. Three types of cells are present in the blood. Blood Cells/Formed elements - 18

19. Production of Blood Cells

20. Red Blood Cells Biconcave in shape Diameter = 7.8 µm Thickness = 2.5 µm 52,00,000/cubic millimeter of blood in males 47,00,000/cubic mm in females The major function of erythrocytes is gas transport; they carry oxygen taken in by the lungs and carbon dioxide produced by the cells. 20

21. The average life span of an erythrocyte is approximately 120 days, which means that almost 1% of the erythrocytes are destroyed and must be replaced every day. This amounts to 250 billion cells per day ! Destruction of damaged or dying erythrocytes normally occurs in the spleen and the liver. Most of the iron released in the process is conserved. The major breakdown product of hemoglobin is bilirubin , which is returned to the circulation and gives plasma its characteristic yellowish color . life span of an erythrocyte

22. 7000 per microliter of blood Types & Role of WBC’s Polymorphonuclear neutrophils 62% Polymorphonuclear eosinophil's 2.3% (allergy, asthma) Polumorphonuclear basophils 0.4% (inflammation) Monocytes 5.3% (phagocytosis) Lymphocytes 30% (cell-mediated immunity, T & B-cells) White Blood Cells The leukocytes are involved in immune defenses. 22

23. 300,000 per microliter of blood. The roles of platelets is in blood clotting . Platelets - 23

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25. - 26 Functions of Blood

26. Functions of Blood Transport of: Gases= O 2 , CO 2 Nutrients= glucose, a.a, fatty acids waste products=CO2, urea, lactic acid Regulatory molecules Regulation of pH Maintenance of body temperature Protection against foreign substances Coagulation - 27

27. Almost makes up 7% of body weight 4.7-5.5 liters in body 20-30 trillion RBCs - 28

28. 1. NUTRITIVE FUNCTION Nutritive substances like glucose, amino acids, lipids and vitamins derived from digested food are absorbed from gastrointestinal tract and carried by blood to different parts of the body for growth and production of energy. - 29

29. 2. RESPIRATORY FUNCTION „ Transport of respiratory gases is done by the blood. It carries oxygen from alveoli of lungs to different tissues and carbon dioxide from tissues to alveoli. - 30

30. 3. EXCRETORY FUNCTION „ Waste products formed in tissues during various metabolic activities are removed by blood and carried to the excretory organs like kidney, skin, liver, etc. for excretion. - 31

31. 4. TRANSPORT OF HORMONES AND ENZYMES Hormones which are secreted by ductless (endocrine) glands are released directly into the blood. The blood transports these hormones to their target organs/tissues. Blood also transports enzymes. 32

32. 5. REGULATION OF WATER BALANCE „ Water content of the blood is freely interchangeable with interstitial fluid. This helps in the regulation of water content of the body. 19- 33

33. „ 6. REGULATION OF ACID-BASE BALANCE Plasma proteins and hemoglobin act as buffers and help in the regulation of acid-base balance. - 34

34. 7. REGULATION OF BODY TEMPERATURE Because of the high specific heat of blood, it is responsible for maintaining the thermoregulatory mechanism in the body, i.e. the balance between heat loss and heat gain in the body. 19- 35

35. „ 8. STORAGE FUNCTION Water and some important substances like proteins, glucose, sodium and potassium are constantly required by the tissues. Blood serves as a readymade source for these substances. And, these substances are taken from blood during the conditions like starvation, fluid loss, electrolyte loss, etc. - 36

36. „ 9. DEFENSIVE FUNCTION Blood plays an important role in the defense of the body. The white blood cells are responsible for this function. Neutrophils and monocytes engulf the bacteria by phagocytosis. Lymphocytes are involved in development of immunity. Eosinophils are responsible for detoxification, disintegration and removal of foreign proteins . - 37

37. Some Diseases related to Blood (Blood Disorders) 19- 38

38. Anemia Anemia is defined as a decrease in the ability of the blood to carry oxygen due to (1) a decrease in the total number of erythrocytes, each having a normal quantity of hemoglobin; (2) a d iminished concentration of hemoglobin per erythrocyte ; or (3) a combination of both . Anemia has a wide variety of causes, some of which are listed in Table 12.11 . Anemia

39. Sickle-cell disease (formerly called sickle-cell anemia ) is due to a genetic mutation that alters one amino acid in the hemoglobin chain . At the low oxygen levels existing in many capillaries, the abnormal hemoglobin molecules interact with each other to form fiber like polymers that distort the erythrocyte membrane and cause the cell to form sickle shapes or other bizarre forms (Figure 12.71). This causes both the blockage of capillaries , with consequent tissue damage and pain, and the destruction of the deformed erythrocytes , with consequent anemia. Anemia…

40. Figure 12.71 Digitally colorized scanning electron micrograph of red blood cells from a patient with sickle cell anemia. The cell at left assumed this sickle shape after exposure to low oxygen conditions.

41. Sickle-cell disease is an example of a disease that is manifested fully only in people homozygous for the mutated gene (that is, they have two copies of the mutated gene, one from each parent). In heterozygotes (one mutated copy and one normal gene), people who are said to have sickle-cell trait, the normal gene codes for normal hemoglobin and the mutated gene for the abnormal hemoglobin. The erythrocytes in this case contain both types of hemoglobin , but symptoms are observed only when the oxygen level is unusually low, as at high altitude. The persistence of the sickle-cell mutation in humans is due to the fact that heterozygotes are more resistant to malaria, a blood infection caused by a protozoan parasite that is spread by mosquitoes in tropical regions.

42. The RBCs of a person with sickle-cell disease (SCD) contain Hb-S, an abnormal kind of hemoglobin. When Hb-S gives up oxygen to the interstitial fluid , it forms long, stiff, rod like structures that bend the erythrocyte into a sickle shape (Figure 19.15). The sickled cells rupture easily . Even though erythropoiesis is stimulated by the loss of the cells, it cannot keep pace with hemolysis .

43. Signs and symptoms of SCD are caused by the sickling of red blood cells. When red blood cells sickle , they break down prematurely ( sickled cells die in about 10 to 20 days ). This leads to anemia, which can cause shortness of breath, fatigue, paleness, and delayed growth and development in children .

44. Hemophilia is an inherited deficiency of clotting in which bleeding may occur spontaneously or after only minor trauma. It is the oldest known hereditary bleeding disorder; descriptions of the disease are found as early as the second century A.D. Hemophilia usually affects males and is sometimes referred to as “ the royal disease ” because many descendants of Queen Victoria , beginning with one of her sons, were affected by the disease. Different types of hemophilia are due to deficiencies of different blood clotting factors and exhibit varying degrees of severity, ranging from mild to severe bleeding tendencies. Hemophilia

45. Hemophilia … Hemophilia is characterized by spontaneous or traumatic subcutaneous and intramuscular hemorrhaging, nosebleeds, blood in the urine, and hemorrhages in joints that produce pain and tissue damage. Treatment involves transfusions of fresh blood plasma or concentrates of the deficient clotting factor to relieve the tendency to bleed. Another treatment is the drug desmopressin (DDAVP), which can boost the levels of the clotting factors .

46. There also exist conditions in which there are more erythrocytes than normal, a condition called polycythemia . An example, is of the polycythemia that occurs in high-altitude dwellers . In this case, the increased number of erythrocytes is an adaptive response because it increases the oxygen-carrying capacity of blood exposed to low oxygen levels . As discussed earlier, however, increasing the hematocrit increases the viscosity of blood . polycythemia.

47. Therefore, polycythemia makes the flow of blood through blood vessels more difficult and puts a strain on the heart . Abuse of synthetic erythropoietin and the subsequent extreme polycythemia have resulted in the deaths of competitive bicyclists—one reason that such “blood doping” is banned in sports. polycythemia.

48. Leukemia The term leukemia ( leuko - white) refers to a group of red bone marrow cancers in which abnormal white blood cells multiply uncontrollably The accumulation of the cancerous white blood cells in red bone marrow interferes with the production of red blood cells , white blood cells, and platelets As a result, the oxygen-carrying capacity of the blood is reduced, an individual is more susceptible to infection, and blood clotting is abnormal

49. In most leukemias , the cancerous white blood cells spread to the lymph nodes, liver, and spleen, causing them to enlarge All leukemias produce the usual symptoms of anemia ( fatigue, intolerance to cold, and pale skin) In addition, weight loss, fever, night sweats, excessive bleeding, and recurrent infections may occur Leukemia…

50. In general, leukemias are classified as Acute (symptoms develop rapidly) and Chronic (symptoms may take years to develop). Leukemias are also classified on the basis of the type of white blood cell that becomes malignant. Lymphoblastic leukemia Myelogenous leukemia Leukemia…

51. Lymphoblastic leukemia involves cells derived from lymphoid stem cells (lymphoblasts) and/or lymphocytes 1. Acute lymphoblastic leukemia (ALL) is the most common leukemia in children, but adults can also get it. Chronic lymphoblastic anemia (CLA) is the most common leukemia in adults, usually those older than 55. Leukemia…

52. Myelogenous leukemia involves cells derived from myeloid stem cells (myeloblasts) 2. Acute myelogenous leukemia (AML) affects both children and adults. 4. Chronic myelogenous leukemia (CML) occurs mostly in adults. Leukemia…

53. The cause of most types of leukemia is unknown. However, certain risk factors have been implicated. These include exposure to radiation or chemotherapy for other cancers, genetics (some genetic disorders such as Down syndrome), environmental factors (smoking and benzene), and microbes such as the human T cell leukemia–lymphoma virus-1 (HTLV-1) and the Epstein–Barr virus. Treatment options include chemotherapy, radiation, stem cell transplantation, interferon, antibodies, and blood transfusion. Leukemia…

54. hemolytic anemia. RBC plasma membranes rupture prematurely in hemolytic anemia. The released hemoglobin pours into the plasma and may damage the filtering units ( glomeruli ) in the kidneys. The condition may result from inherited defects such as abnormal red blood cell enzymes , or from outside agents such as parasites, toxins, or antibodies from incompatible transfused blood . hemolytic anemia.

55. Thalassemia Deficient synthesis of hemoglobin occurs in thalassemia , a group of hereditary hemolytic anemias . The RBCs are Small ( microcytic ), Pale ( hypochromic ), and Short-lived . Thalassemia occurs primarily in populations from countries bordering the Mediterranean Sea. Thalassemia is a treatable disorder that can be well-managed with blood transfusions and chelation therapy. Thalassemia and aplastic anemia .

56. Clinically,  Thalassemia is classified into three forms: Thalassemia major: this is a severe form of anaemia where patients need continuous blood transfusions throughout their lives. Thalassemia intermedia: mild to moderate anaemia, patients occasionally need blood transfusions Thalassemia minor or trait: patients have mild symptoms and they usually don’t need blood transfusions.

57. Aplastic anemia Destruction of red bone marrow results in aplastic anemia. It is caused by toxins, gamma radiation, and certain medications that inhibit enzymes needed for hemopoiesis . Thalassemia and aplastic anemia .

58. Thank you ! BEST WISHES 

59. Practice MCQs  19- 64

60. What is normal erythrocyte count? (a)1 -2 million/ microliter (b) 4-5 million/ micrometer (c)1-3million/micrometer (d) 3-4 million/micrometer 2. What is normal hemoglobin concentration? (a)11.5-17.5gm/100ml (b)12.5-17.5gm/100ml (c)13.5-17.5gm/100ml (d)14.5-17.5gm/100ml 3. Special kind of protein containing iron is called as? Hormones (b) hemoglobin (c) RBCs (d)WBCs 4.Structural component of hemoglobin is ? Manganese (b) zinc (c) iron (d) chlorine 5. Red blood cell (Rbcs) Have nucleus (b) can repair damage through new protoplasm (c) Are destroyed in spleen (d) are permanent cell

61. Bile obtained after breakage of hemoglobin is of ? Red color (b) bright pink color (c) blue color (d) Greenish yellow color 7. The______ Produces red blood cells, which transport ______ and some__________? Liver, oxygen ,minerals (b) liver, oxygen, carbon dioxide (c) Bone marrow, oxygen, hormone (d) Bone mrrow,oxygen,co2 8 . The percentage of packed RBCS in comparison of whole blood is called as? Hemachromasia (b) hematrocit (c) Hemoglobin (d) hematology

62. 9. Elasticity of red blood cells helps them to ? Pass through capillaries easily (b) absorb oxygen easily (c) Release co2 easily (d) moves in the veins easily 10. A pigment of red blood cell which makes color of blood ‘red’ is known as? (a) plasma (b) hemoglobin (c) fibrin (d) fibrinogen 11. Select the statement about red blood cells that is incorrect? Mature red blood cell lack nuclei (b) red blood cell contain hemoglobin (c) deoxyhemoglobin carries oxygen (d) red blood cell lack mitochondria

63. 12. Which of the following directly defines the transportation of oxygen? Hemoglobin (b) oxyhemoglobin (c ) de oxyhemoglobin (d) Red cell count 13. Which blood cell can be described as being a biconcave disc? Platelets (b) neutrophil (c) eosinophil (d) erythrocyte 14. The 1 st step of heme synthesis take places in the ? Mitochondria (b) Golgi appratus (c ) peroxisome ( d) nucleolus

64. Which of the following treatments would prevent a transfusion reaction ? Administration of plasma free blood (b) administration of washed erythrocytes (c) immunoglobulin (d) proper cross matching of donor’s RBCs with recipient plasma 16. The protein responsible for iron transport in plasma is ? Ferritin (b) Apo-transferrin (c) Apo- ferritin (d) ceruloplasmin 17. Bluish tint of the polycythemia person is because of excess of ? Myoglobin (b) deoxygenated HB (c ) oxygenated HB (d) reduced HB

65. 18. Lesions called ‘’hives’’ are a feature of ? Hay fever (b) Asthma ( c) urticarial (d) anaphylaxis 19. The most abundant cell of the blood is? Erythrocytes (b) platelets (c) granulocyte (d) leukocytes 20. Bilirubin is ? Not bound with albumin (b) is a useful body pigment ( c) converting into colorless urobilinogen (d) no conjugated in liver 19- 70