This is all about Blood Physiology

1. Blood
Presented by Ali Haider
UW-16-BIS-BS-055

2. Fluid of Life
• Fundamental component of human life.
• Within the adult body, approximately 4 to 5 litters (1 to 1.3 gallons) of blood
circulates
• While circulating it comes in contact with cells.
• Supply nutrients to all cells and picks cellular waste
• Blood is one of the most easily accessed and readily examined tissues of the
human body.

3. Blood both Tissue and Fluid
• Blood is both a tissue and a fluid.
• Tissue:
• It is a tissue because it is a collection of similar specialized cells that serve
particular functions.
• Fluid:
• These cells are suspended in liquid matix that’s why blood is fluid.

4. Variation among Kingdom Animalia
• Lower invertebrates lacks circulatory System.
• E.g: Sponges and coelenterates
• Invertebrates have various large blood cells capable of amoeboid movement, some
of which aid in transporting substances while other are capable of surrounding and
digesting foreign particles or debris (phagocytosis).

6. • Among the vertebrates, there are several classes of amoeboid cells (white blood
cells, or leukocytes) and cells that help stop bleeding (platelets, or thrombocytes).
• Larger and more complex animals, which have greater oxygen needs, have
pigments capable of transporting relatively large amounts of oxygen. The red
pigment hemoglobin, which contains iron, is found in all vertebrates and in some
invertebrates.

7. Blood Components
• Blood is an opaque red fluid, freely flowing but denser and more viscous than
water.
• The characteristic color is imparted by hemoglobin.
• Hemoglobin brightens in colour when saturated with oxygen
(oxyhemoglobin) and darkens when oxygen is removed
(deoxyhemoglobin).

8. • Cellular Components:
• Red blood cells constitute about 45% of the volume of the blood
• The remaining white blood cells and platelets less than 1 percent.
• Fluid Portion:
• The fluid portion, plasma, is a clear, slightly sticky, yellowish liquid. After a fatty
meal, plasma transiently appears turbid.

10. Plasma
• The liquid portion of the blood
• Containing more than 90% water.
• Functions:
1. Transport medium for delivering nutrients to the cells
2. Role in maintaining normal blood pressure.
3. Helps to distribute heat throughout the body.

11. Components of Plasma
• Proteins are the most abundant
• About 7% of the plasma by weight.
• Difference between the plasma and the extracellular fluid
• Mainly difference is the high protein content of the plasma.

12. Components of Plasma
Plasma
Water 90% Dissolved solutes 10% Gases
O2 and CO2
Organic Substances 9.1% Inorganic Substances 0.1%
Na+ ,Ca++ ,K+ ,Cl-,PO42-
Proteins 7%
2%
Lipids, Amino Acids, Glucose

13. Plasma Proteins
• Plasma proteins exerts an osmotic effect by which water tends to move from other
extracellular fluid to the plasma.
• The dietry amino acids are absorbed from Gastro intestinal tract
• They are transported through blood plasma and taken by cells where they require.

15. • Plasma Proteins are produced in the liver.
• Release into blood from cell which synthesize them.

16. Serum albumin
• Major plasma protein is serum albumin.
• approximately 60% of all of the plasma proteins
• the principal function of which is to retain water in the bloodstream by its osmotic
effect.
• Non Specific Carrier Protein.

17. Edema
• Depletion of serum albumin permits
• Fluid to leave the circulation
• Accumulation in tissues
• Causes swelling of soft tissues called edema.

19. Globulins
• Heterogeneous array of proteins of widely varying structure and function
• Immunoglobulins (antibodies):
• Secreted by cells of the immune system known as B cells (or B lymphocytes).
• Produced in response to specific substance, Antigen.
• Involved in Allergic reaction.

21. Cytokines
• Small, short-lived proteins
• Serve as intercellular chemical messengers that regulate blood cell formation
(hematopoiesis).
• Defense against disease causing organisms.
• Stimulate production of WBCs and Platelets.

22. Erythropoietin
• Cytokine
• Synthesized by specialized kidney cells
• Stimulates bone marrow blood progenitor cells to produce red blood cells

24. Complement
• Plasma protein
• Important in mediating appropriate immune and inflammatory responses to a
variety of infectious agents.

25. Lipoproteins
• Blood lipids + Proteins
• Transported proteins
1. Transferrin and Ceruloplasmin:
• Metal-binding proteins
• Iron and copper are transported in plasma

26. 2. Alpha and beta globulins
• Transport sugar and cholesterol
3. Haptoglobin
• Hemo globin binding protein
• Carry it to reticuloendothelial where hemolysis occur
• Level rise in inflammation

27. Coagulation proteins inhibitors
• Synthesized primarily in the liver
• Prevent abnormal coagulation (hypercoagulability) and to resolve clots after they
are formed.

28. Lipids
• Present in Plasma suspension and in solution
• Concentration varies but not exceed 1g per 100ml.
• Different types of Lipids
• Phospholipids
• Triglycerides
• Free Fatty acids
• Chylomicrons

29. Low concentration Compounds:
1.Glucose (blood sugar):
• source of energy for tissue cells and for some cells like red cells
• Not excreted normaly
2.Amino Acids:
• rapidly transported that the plasma level remains low
• Require for protein synthesis throughout body

30. Inorganic materials
Cation of Plasma
• Sodium (Na+)
• Potassium (K+)
• Calcium (Ca2+)
• Magnesium (Mg2+)
Anions of Plasma
• Chloride (Cl-)
• Bi carbonate (HCO3-)
• Phosphate (PO4
2-)

31. Blood Cells
• Four types of Cells
1. Red blood cells,
2. Platelets (thrombocytes),
3. Lymphocytes,
4. Phagocytic cells.
• Collectively, the lymphocytes and phagocytic cells constitute the White blood
cells.

32. Hematopoiesis:
• Process of blood cell formation is called hematopoiesis.
• hematopoietic tissue.
• Sites:
• In developing embryo. the first site of blood formation is the yolk sac.
• Later in embryonic life, the liver becomes the most important red blood cell-
forming organ.

33. Hematopoiesis
• It is soon succeeded by the bone marrow, which in adult life is the only source of both red
cells and the granulocytes.
• Central bones in adult produces Blood Cells.
• Ribs,
• Sternum,
• Vertebrae,
• Pelvic bones.

35. Hematopoiesis
• The blood cells begin their lives in the bone marrow from a single type of cell
called the pluripotent hematopoietic stem cell.
• The successive divisions of the pluripotent cells to form the different circulating
blood cells.
• Small portion of them remains exactly like the original pluripotent cells and is
retained in the bone marrow to maintain a supply of these cells, although their
numbers diminish with age.

36. Hematopoiesis
• The intermediate stage cells are very much like the pluripotent stem cells, even
though they have already become committed to a particular line of cells and are
called committed stem cells.
• The different committed stem cells, when grown in culture, will produce colonies
of specific types of blood cells.

37. Hematopoiesis
• Colony forming Unit:
• A committed stem cell that produces erythrocytes is called a colony-
forming unit–erythrocyte, and the abbreviation CFU-E is used to
designate this type of stem cell.
• Likewise, colony-forming units that form granulocytes and monocytes have the
designation CFU-GM, and so forth.

38. Hematopoiesis
• Growth inducers:
• Growth and reproduction of the different stem cells are controlled by multiple
proteins called growth inducers.
• Do not promote differentiation of the cells.

39. • Four major growth inducers
• interleukin-3, promotes growth and reproduction of virtually all the
different types of committed stem cells,
• Others induce growth of only specific types of cells.

40. Hematopoiesis
• Differentiation inducers:
• Causes one type of committed stem cell to differentiate one or more steps toward a
final adult blood cell.
• Formation of the growth inducers and differentiation inducers is itself controlled
by factors outside the bone marrow.
• Some events cause increase of Growth induction and differentiation different
blood cells as requirement.

42. Red Blood Cells:
• Millions of Red blood cells circulate in blood and give it to characteristic
color.
• Function :
• Carry oxygen from the lungs to all the body tissues
• Transport carbon dioxide, a waste product of metabolism, to the lungs, where it is
excreted.

43. Adaptation of Red Blood Cells
• Oxygen-carrying pigment is concentrated in red cells in vertebrates
• This represents an important evolutionary development relative to invertebrates, in
which the pigment circulates freely, not contained within cells. The mammalian
red cell is further adapted by lacking a nucleus---the amount of oxygen required
by the cell for its own metabolism is thus very low, and most oxygen carried can
be freed into the tissues.

44. Shape and Size of Red Blood Cells
• Normal red blood cells,are biconcave discs
• Having a mean diameter of about 7.8 micrometers
• Thickness of 2.5 micrometers at the thickest point and 1 micrometer or less in the
center.
• The average volume of the red blood cell is 90 to 95 cubic micrometers.

46. Concentration Red Blood Cells in the Blood
• In normal,the average number of red blood cells
• Men= 5,200,000 (±300,000)/ml3
• Women=4,700,000 (±300,000) /ml3 .

47. Hemolysis
• Red cell membranes are damaged,
• hemoglobin and other dissolved contents may escape from the cells, leaving the
membranous structures as “ghosts.”
• This process, called hemolysis.
• It is produced not only by the osmotic effects of water but also by numerous other
mechanisms

48. • These include;
• Physical damage to red cells, as when blood is heated, is forced under great
pressure through a small needle, or is subjected to freezing and thawing,
• Chemical damage to red cells by agents such as bile salts, detergents, and
certain snake venoms; and damage caused by immunologic reactions that may
occur when antibodies attach to red cells in the presence of complement.

50. Hemoglobin
• Hemoglobin is the iron-containing protein found in the red blood cells that
transports oxygen to the tissues.
• Hemoglobin forms an unstable, reversible bond with oxygen
• In the oxygenated state, it is called oxyhemoglobin and is bright red.
• In the reduced state, it is purplish blue and may be referred to as
deoxyhemoglobin.

51. Heamoglobin molecule
• Each hemoglobin molecule has a tetrahedral structure. A hemoglobin protein
assumes this structure
• It contains four polypeptide chains (a tetramer),
• Each chain consisting of more than 140 amino acids.

52. Heam group
• To each chain is attached a chemical structure known as a heme group.
• Heme accounts for about 4% of the weight of hemoglobin
• It is composed of a ring like organic compound known as a porphyrin, to which an
iron atom is attached.

53. Iron atom
• It is the iron atom that reversibly binds oxygen as the blood travels between the
lungs and the tissues.
• There are four iron atoms in each molecule of hemoglobin, which can bind four
atoms of oxygen.

55. Affinities of Haemoglobin for gases
1. Affinity of hemoglobin for oxygen
• The affinity of hemoglobin for oxygen is so great that at the oxygen pressure in
the lungs is about 95% of the haemoglobin is saturated with oxygen.
2. Affinity for Carbon monoxide
• Hemoglobin has a much higher affinity for carbon monoxide than for oxygen.
Carbon monoxide produces its lethal effects by binding to haemoglobin and
preventing oxygen transport.

56. White Blood Cells
• White blood cells (or leukocytes, sometimes called white corpuscles),
• They are;
nucleated,
motile,
lack haemoglobin.
• They serve as to defend the body against infection and disease

57. Concentration of White Blood Cells in the Blood
• The number of white cells in normal blood ranges between
4,500 and 11,000/ ml3.
• Fluctuations occur during the day
• Lower values are obtained during rest
• higher values during exercise.

58. Life Span of the White Blood Cells
• The life of the granulocytes after being released from the bone marrow
is normally 4 to 8 hours circulating in the blood and another 4 to 5
days in tissues where they are needed.
• In times of serious tissue infection, this total life span is often shortened to only a
few hours.

59. Classes of White Blood Cells
• White cells are grouped into following three major classes,
• Each of which carries out somewhat different functions.
1. Granulocytes,
2. Monocytes,
3. Lymphocytes.

60. Granulocytes
• Granulocytes are characterized by the large number and chemical makeup of the
granules occurring within the cytoplasm.
• The granules, or secretory vesicles, harbour potent chemicals important in immune
responses.
• These cells are important mediators of the inflammatory response.

61. • Granulocytes are the most numerous of the white cells
• They are approximately 12–15 micrometers in diameter.
• They also have a multi lobed nucleus, and because of this they are often called
polymorph-nuclear cells.

62. • The three types of granulocytes are;
1. Neutrophils,
2. Eosinophils,
3. Basophils.

63. Neutrophils
• Neutrophils are the most numerous of the granulocytes
• They make up about 50 to 80% of all the white bloods cells occurring in the
human body.
• The neutrophils are in size with a diameter between 12 and 15 micrometers.
• The bone marrow of a normal adult produces about 100 billion neutrophils daily.

64. Function of Neutrophils
• Neutrophils are actively phagocytic.
• They engulf bacteria and other microorganisms and microscopic
particles.
• They produce mediating immune responses against infectious
microorganisms.

65. Eosinophils
• Eosinophils are rare, making up less than 1 percent of the total number of white
blood cells.
• Granules of eosinophils typically stain red
• Produced in bone marrow and then released in circulation
• Eosinophils leave the circulation within hours of release from the marrow and
migrate into the tissues through lymphatic duct

66. Function of Eosinophils
• These are;
• Eosinophils are actively motile and phagocytic
• They participate in hypersensitivity and inflammatory reactions.
• Eosinophils and antibodies of the immunoglobulin E (IgE) class work together to
destroy parasites such as the flatworms that cause schistosomiasis.

67. Basophils
• Basophils are the least numerous of the granulocytes and account for less than 1
percent of all white blood cells occurring in the human body
• Basophils contain large granules that stain purple black in color
• Within hours of their release from the bone marrow, basophils migrate from the
circulation to the barrier tissues (e.g., the skin and mucosa), where they synthesize
and store histamine, a natural modulator of the inflammatory response.

68. Function of Basophils
• When antibodies of the IgE class bind to specialized receptor molecules on
basophils, the cells release their stores of inflammatory chemicals, including
histamine, serotonin, and leukotrienes.
• These chemicals have a number of effects, including constriction of the smooth
muscles, which leads to breathing difficulty; dilation of blood vessels, causing
skin flush and hives; and an increase in vascular permeability, resulting in swelling
and a decrease in blood pressure.

69. Monocytes
• Monocytes are the largest cells of the blood (averaging 15–18 micrometers).
• The nucleus is relatively big and tends to be indented or folded rather than multi
lobed.
• The cytoplasm contains large numbers of fine granules, which often appear to be
more numerous near the cell membrane.

70. Macrophages Development
• In the bone marrow, granulocytes and monocytes arise from a common precursor
under the influence of the granulocyte-macrophage colony-stimulating factor.
• Monocytes leave the bone marrow and circulate in the blood.
• After a period of hours, the monocytes enter the tissues, where they develop into
macrophages, the tissue phagocytes that constitute the reticuloendothelial system
(or macrophage system).

71. • Macrophages occur in almost all tissues of the body:
• Those in the liver are called Kupffer cells,
• Those in the skin called Langerhans cells.

72. Lymphocytes
• Lymphocytes constitute about 28–42 percent of WBCs.
• Lymphocytes are found in large numbers in;
1. Lymph nodes,
2. Spleen,
3. Thymus,
4. Tonsils,
5. Lymphoid tissue of the gastrointestinal tract.

73. Functions of Lymphocytes
• The lymphocytes regulate or participate in the acquired immunity to foreign cells
and antigens.
• They are responsible for immunologic reactions to invading organisms, foreign
cells such as those of a transplanted organ, and foreign proteins and other antigens
not necessarily derived from living cells.

74. Classes of lymphocytes
• The two classes of lymphocytes originally derived their names from investigations
in birds, in which it was found that differentiation of one class of lymphocyte was
influenced by the bursa of Fabricius (an outpouching of the gastrointestinal tract)
and thus was called the B cells.
• The other was influenced by the thymus and called the T cells.

75. B lymphocytes
• The B lymphocytes (or B cells) are involved in what is called humoral immunity.
Upon encountering a foreign substance (or antigen), the B cell differentiates into a
plasma cell, which secretes immunoglobulin (antibodies).
• All lymphocytes begin their development in the bone marrow. The B cells mature partly
in the bone marrow until they are released into the circulation. Further differentiation of B
cells occurs in lymphoid tissues (spleen or lymph nodes), most notably on stimulation by
a foreign antigen.

76. T lymphocytes
• The T lymphocytes (or T cells), are involved in regulating the antibody-forming function
of B cells as well as in directly attacking foreign antigens.
• T cells participate in what is called the cell-mediated immune response, in the rejection of
transplanted tissues, and in certain types of allergic reactions.
• The precursors of the T cells migrate from the marrow to the thymus, where they
differentiate under the influence of a hormone like substance.Once they have
matured, the T cells leave the thymus and circulate through the blood to the lymph
nodes and the spleen.

77. Classes of T cells
• Cytotoxic T cells, which destroy the cells by a lytic mechanism, and helper T
cells, which assist B cells to produce antibodies against the microbial antigens.
• Helper T cells, exert their influence on B cells through several hormone like
peptides termed interleukins (IL). Five different T cell interleukins (IL-2, IL-3, IL-
4, IL-5, and IL-6) have been discovered, each with different (and sometimes
overlapping) effects on B cells and other blood cells.

79. Platelets
• The blood platelets are the smallest cells of the blood, averaging about 2-4
micrometers in diameter.
• They lack a nucleus and are incapable of cell division (mitosis)
• When seen in fresh blood they appear spheroid
• They adhere to each other but not to red cells and white cells.

80. Concentration of Platelets in Blood
• The concentration of platelets in Blood is;
150,000-400,000/ml3.

81. Formation of Platelets
• Platelets are formed in the bone marrow by segmentation of the cytoplasm (the
cell substance other than the nucleus) of cells known as megakaryocytes, the
largest cells of the marrow. Within the marrow the abundant granular cytoplasm of
the megakaryocyte divides into many small segments that break off and are
released as platelets into the circulating blood.
• After about 10 days in the circulation, platelets are removed and destroyed.

82. Thromobopoietin
• The rate of platelet production is controlled but not so precisely as the control of
red cell production.
• A hormone like substance called thrombopoietin is believed to be the chemical
mediator that regulates the number of platelets in the blood by stimulating an
increase in the number and growth of megakaryocytes, thus controlling the rate of
platelet production.

83. Function of Platelets
• The function of the platelets is;
1. Homeostasis,
2. Prevention and Control of bleeding.

84. Functions of Blood
1. Respiration
Oxygen is transported by the blood, most of it bound to the hemoglobin of the red
cells. The minute blood vessels of the lungs bring the blood into close apposition
with the pulmonary air spaces (alveoli), where the pressure of oxygen is relatively
high.

85. 2. Nutrition
Each food substance required for the nutrition of every cell in the body is
transported by the blood.
The materials may enter the bloodstream from the gastrointestinal tract, or they may
be released from stores within the body or become available from the breakdown of
tissue.

86. 3.Excretion
• The blood carries the waste products of cellular metabolism to the excretory
organs.
• Water produced by the oxidation of foods or available from other sources in
excess of needs is excreted by the kidneys as the solvent of the urine, and water
derived from the blood also is lost from the body by evaporation from the skin and
lungs as well as in small amounts from the gastrointestinal tract.

87. 4. Homeostasis
Even the bumps and knocks of everyday life are sufficient to disrupt some of these
fragile vessels, and serious injury can be much more damaging. Blood loss would be
a constant threat to survival if it were not for protective mechanisms to prevent and
control bleeding.

88. 5. Immunity
Cells of the blood and constituents of the plasma interact in complex ways to confer
immunity to infectious agents, resist or destroy invading organisms, produce the
inflammatory response, and destroy and remove foreign materials and dead cells.

89. 6.Temperature Regulation
Heat is produced in large amounts by physiological oxidative reactions, and the
blood is essential for its distributing and disposing of this heat. The circulation
assures relative uniformity of temperature throughout the body and also carries the
warm blood to the surface, where heat is lost to the external environment.

90. Blood Coagulation
General Mechanism
(1) Formation of a complex of activated substances collectively called prothrombin
activator.
(2) Conversion of prothrombin into thrombin.
(3) Conversion of fibrinogen into fibrin fibers that enmesh platelets, blood cells, and
plasma to form the clot.

92. Clotting Factor Synonyms
Fibrinogen Factor I
Prothrombin Factor II
Tissue factor Factor III; tissue thromboplastin
Calcium Factor IV
Factor V Proaccelerin; labile factor
Factor VII Serum prothrombin conversion
accelerator
Factor VIII Antihemophilic factor (AHF);
Antihemophilic factor A
Factor IX Plasma thromboplastin component (PTC);
Christmas factor; Antihemophilic factor B
Factor X Stuart factor; Stuart-Prower factor
Factor XI Plasma thromboplastin antecedent (PTA);
Factor XII Hageman factor
Factor XIII Fibrin-stabilizing factor
Platelets

93. Anti Coagulants for Clinical use
1.Heparin as an Intravenous Anticoagulant
Commercial heparin is extracted from several different animal tissues and prepared
in almost pure form. Injection of relatively small quantities, about 0.5 to 1 mg/kg of
body weight.

94. 2.Coumarins as Anticoagulants
When a coumarin, such as warfarin, is given to a patient, the plasma
levels of prothrombin and Factors VII, IX, and X, all formed by the
liver, begin to fall, indicating that warfarin has a potent depressant effect
on liver formation of these compounds.

95. Blood Typing
• The classification of blood in terms of distinctive inherited characteristics that are
associated with the antigens located on the surface of red blood cells is known as
blood typing.
• The ABO and the Rh blood groups are among those most commonly considered.

96. ABO Blood Group System
• It is based on determined by the presence or absence of the antigens A
and B.
• Persons may thus have type A, type B, type O, or type AB blood.

97. Discovery
• The A, B, and O blood groups were first identified by Austrian
immunologist Karl Landsteiner in 1901.

98. Antigens and Antibodies
Blood Type Antigens Antibody
A A B
B B A
O nil AB
AB AB nil

99. MNSs Blood Group System
• The system consists of two pairs of codominant alleles designated as
• M and N (identified in 1927)
• S and s (identified 1947 and 1951, respectively).

100. Rh Blood Group System
• The Rh blood group system is based on the presence or absence of the
Rh antigen, often called the Rh factor, on the cell membranes of the
red blood cells.

101. Discovery
• Rh blood group system was discovered in 1940,the designation Rh is derived from
the use of the blood of rhesus monkeys in the basic test for determining the
presence of the Rh antigen in human blood.

102. Erythroblastosis fetalis
• When the mother is Rh-negative and the father is Rh-positive.
• The first child of such parents is Rh+.
• During labour, however, a small amount of the fetus’s blood may enter the
mother’s bloodstream. The mother will then produce anti-Rh antibodies, which
will attack any Rh-incompatible fetus in subsequent pregnancies. This process
produces erythroblastosis fetalis.

104. Diseases related to Red Blood Cells
1. Anemias
• Anemia means deficiency of hemoglobin in the blood.
• Signs and symptoms
• Fatigue, Weakness, Pale or yellowish skin, Irregular heartbeats, Shortness of
breath

105. Diseases related to Red Blood Cells
Types of Anemia
1.Blood Loss Anemia
• After rapid hemorrhage, the body replaces the fluid portion of the plasma in 1 to 3 days,
but this leaves a low concentration of red blood cells. If a second hemorrhage does not
occur, the red blood cell concentration usually returns to normal within 3 to 6 weeks.
• In chronic blood loss, a person frequently cannot absorb enough iron from the intestines
to form hemoglobin as rapidly as it is lost.

106. Diseases related to Red Blood Cells
2. Aplastic Anemia
• Bone marrow aplasia means lack of functioning bone marrow.
• For instance, a person exposed to gamma ray radiation from a nuclear bomb blast
can sustain complete destruction of bone marrow, followed in a few weeks by
lethal anemia.

107. Diseases related to Red Blood Cells
3. Megaloblastic Anemia
• Vitamin B12, folic acid, from the stomach mucosa, loss of any one of these can lead to
slow reproduction of erythroblasts in the bone marrow.
• As a result, the red cells grow too large, with odd shapes, and are called megaloblasts.
• Thus, atrophy of the stomach mucosa, as occurs in pernicious anemia, or loss of the entire
stomach after surgical total gastrectomy can lead to megaloblastic anemia.

108. Diseases related to Red Blood Cells
4.Hemolytic Anemia
• Different abnormalities of the red blood cells, many of which are hereditarily
acquired, make the cells fragile, so that they rupture easily as they go through the
capillaries, especially through the spleen.

109. • Hereditary spherocytosis:
• In hereditary spherocytosis, the red cells are very small and spherical
rather than being biconcave discs. These cells cannot withstand
compression forces because they do not have the normal loose, baglike
cell membrane structure of the biconcave discs.

110. Diseases related to Red Blood Cells
Sickle Cell anemia
• The red blood cells have an abnormal type of hemoglobin called hemoglobin S,
containing faulty beta chains in the hemoglobin molecule.
• When this hemoglobin is exposed to low concentrations of oxygen, it precipitates
into long crystals inside the red blood cell. These crystals elongate the cell and
give it the appearance of a sickle rather than a biconcave disc.

112. Diseases related to Red Blood Cells
2. Polycythemia
Secondary Polycythemia:
Whenever the tissues become hypoxic because of too little oxygen in the breathed
air, such as at high altitudes, or because of failure of oxygen delivery to the tissues,
such as in cardiac failure, the blood-forming organs automatically produce large
quantities of extra red blood cells. This condition is called secondary polycythemia

113. Diseases related to Red Blood Cells
• Physiologic polycythemia
• A common type of secondary polycythemia, called physiologic polycythemia,
occurs in natives who live at altitudes of 14,000 to 17,000 feet, where the
atmospheric oxygen is very low. The blood count is generally 6 to 7 million/mm3.

114. Diseases related to Red Blood Cells
• Polycythemia Vera (Erythremia)
• Polycythemia vera is caused by a genetic aberration in the hemocytoblast cells that
produce the blood cells. The blast cells no longer stop producing red cells when
too many cells are already present. This causes excess production of red blood
cells

115. Diseases related to White blood cells
Leukopenia
• A clinical condition known as leukopenia occasionally occurs in which the bone
marrow produces very few white blood cells, leaving the body unprotected against
many bacteria and other agents that might invade the tissues

116. Diseases related to White blood cells
Leukemia
• Uncontrolled production of white blood cells can be caused by cancerous mutation
of a myelogenous or lymphogenous cell.
1. Lymphocytic leukemia
• Cancerous production of lymphoid cells, usually beginning in a lymph node or
other lymphocytic tissue and spreading to other areas of the body.

117. Diseases related to White blood cells
2. Myelogenous leukemia
• It begins by cancerous production of young myelogenous cells in the bone marrow
and then spreads throughout the body so that white blood cells are produced in
many extramedullary tissues—especially in the lymph nodes, spleen, and liver.

118. Diseases related to Platelets
Thrombocytopenia
• Thrombocytopenia is an abnormally low number of platelets (thrombocytes) in the
circulation.
• When the platelet count drops to 50,000 to 75,000 per cubic millimeter, and
particularly to 10,000 to 20,000 per cubic millimeter, spontaneous bleeding may
occur.

119. Blood analysis
• Blood analysis is used to obtain information about the physical and chemical
properties of blood.
1. Serological tests
2. Blood Cell Count
3. Coagulation Tests
4. Hematocrit

120. Blood Cell Count
• A complete blood count (CBC) is a measure of the hematologic parameters of the
blood. Included in the CBC is the calculation of the number of red blood cells (red
blood cell count) or white blood cells (white blood cell count) in a cubic
millimeter (mm3) of blood, a differential white blood cell count, a hemoglobin
assay, a hematocrit, calculations of red cell volume, and a platelet count.

121. Coagulation Tests
• Bleeding disorders are suspected when blood is seen in the skin (purpura) or when
a wound is delayed in clotting.
• Screening tests for coagulation disorders include the prothrombin time (PT) test,
the activated partial thromboplastin time (APTT) test, and the plasma fibrinogen
assay.

122. Hematocrit
• The hematocrit is a diagnostic procedure that is used for the analysis of blood.
• The name is also used for the apparatus.
• In the procedure, an anticoagulant is added to a blood sample held in a calibrated
tube. The tube is allowed to stand for one hour, after which the sedimentation rate
(how rapidly blood cells settle out from plasma) is determined.

123. Serological tests
• Serological tests are any of several laboratory procedures carried out on a sample
of blood serum. The purpose of such a test is to detect serum antibodies or
antibody-like substances that appear specifically in association with certain
diseases.

124. Blood Bank
• An organization that collects, stores, processes, and transfuses blood is known as a
blood bank.
• First blood bank in 1932
• Whole blood is donated and stored in units of about 450 ml.
• Whole blood can be stored only for a limited time, but various components (e.g.,
red blood cells and plasma) can be frozen and stored for a year or longer.