COMPOSITIONON OF BLOOD

 Total blood volume: 5-6 litres (8% of body weight or 80 mL/ kg body weight)
 pH 7.4 ± 0.05; alkaline '
 If anticoagulated sample of blood is allowed to stand in a narrow tube, on settling it separates
out into cells and plasma.

CELLS

 The cellular elements of blood represents 45% of the total blood volume, called Packed Cell
Volume (PCV) or Haematocrit.
 It includes:
1. Erythrocytes or Red Blood Corpuscles (RBC's): Normal count: 5 million/ µL (5 x 10 6/µL).
2. Leucocytes or White Blood Corpuscles (WBCs):Normal count: 4,000- 11,000/µL (4-11 x
103/ µL).
3. Platelets or Thrombocytes: Normal count: 1.5-4 lacs/ µL (0.15 - 0.4 x 106/ µL).

PLASMA

 Plasma is a clear, straw coloured fluid portion of the blood and represents 55% of the total
blood volum (about 5% of body weight). It contains:
 91 % water;
 9% solids.
 The solids comprise:
 1 % inorganic molecules, and
 8% organic molecules.

  The major inorganic molecules are:
 Na+ ,Ca2+, cl- ,HCO3- (mainly extracellular).
 K+, Mg2+, Cu2+, PO4-, Protein- (mainly intracellular).
 Fe2+, Fe3+.

 Of 8% total organic molecules:

 7% are plasma proteins;
 1 % are other substances like Non-protein Nitrogenous (NPN) substances, sugar, fats
enzymes and hormones.

PLASMA PROTEINS

 Normal value: 6.4-8.3 gm/ dL

 Albumin : 3-5 gm/ dL (Average: 4.8 gm/ dL)
 Globulin : 2-3 gm/ dL (Average: 2.3 gm/ dL)
 a-Globulin
 B-Globulin
 y-Globulin
 AIG ratio; Albumin: Globulin : : 1.7 : 1
 Fibrinogen : 0.3 gm/ dL
 Prothrombin : 40 mg/ dL

NON-PROTEIN NITROGENOUS (NPN) SUBSTANCES

 Normal: 28-40 mg/ dL

 These are derivatives of food and in parts are the waste products of tissue catabolism.
 These include:
1. Urea
2. Uric acid
3. Creatine
4. Creatinine
5. Xanthine Traces
6. Hypoxanthine Traces

 Other Substances

 These include:

1. Neutral fats (triglycerides)

2. Phospholipids e.g., Lecithin, sphingomyelin, cephalin etc.
3. Glucose (fasting): 70-90 mg/ dL
4. Cholesterol
FUNCTIONS OF BLOOD

RESPIRATORY

 Blood transports oxygen from lungs to the tissues and of carbon-dioxide from the tissues to the
lungs.

NUTRITIVE

 Blood conveys absorbed food materials, glucose, amino acids, fatty acids, vitamins,
electrolytes and trace metals from the alimentary canal to the tissues for utilization and
storage.

EXCRETORY

 Blood transports the metabolic wastes e.g. urea, uric acid, creatinine etc. to the kidney, skin
and intestine for their removal.

'HOMEOSTATIC'

 for water, pH and electrolyte concentration: Blood forms internal environment of the cell i.e.
Millieu Interieur in terms of volume, composition, concentration, pH and temperature, which is
regulated to normal physiological limits with respect to minor changes in the body. This
mechanism is called Homeostasis (W.B. Cannon). Buffering power of haemoglobin helps to
maintain constancy of blood pH.

REGULATION OF BODY TEMPERATURE

 Blood preserves the very narrow range in body temperature. How?

 Blood whose major constituent is water has:
 (i) High specific heat - This buffers sudden change (rise or fall) in body temperature.
 (ii) High conductivity- This helps to take out heat from an organ for uniform distribution
throughout the body.
 (iii) High latent heat of evaporation.

CHEMICAL FOR COMMUNICATION AND PROTECTION

 Concentration of hormones and various substances in the blood is regulated through feedback
mechanisms.
 Within blood circulates the entire complex of humoral antibodjes important in defence against
infection, initiation of inflammation and regulation of Haemostasis (clotting mechanism).

PLASMA PROTEIN FUNCTIONS

 Exerts the osmotic pressure which influen ces the exchange of fluid between blood and tissues.
 Acts as a reservoir of proteins.
  Combines with many substances e.g. iron, thyroxine and steroid hormones to form
transportable
 complexes from which the active components are released at the appropriate sites.

SERUM

 If the blood is allowed to clot in a test tube, then the clot retracts and gives out serum.
 Therefore, serum is plasma minus fibrinogen and clotting factors (II, V and VIII), because these
factors get consumed during clotting (remaining do not).
 Serum has a higher serotonin (5 hydroxytryptamine - SHT) content because of the breakdown of
platelets during clotting.
PLASMA PROTEINS
ORIGIN OF PLASMA PROTEINS

 In Embryo: Mesenchymal cells through a process of secretion or dissolution of their substances,

form plasma proteins.
 First the albumin is synthesized and rest of plasma proteins afterwards.
 In Adults
 Albumin from liver mainly
 Fibrinogen also from the liver
 Globulin from:
(a) Tissue macrophages, Liver (specially synthesize a and globulin), spleen and bone
marrow.
(b) Plasma cells
(c) Lymphocytes synthesize λ-globulin.

FORMS OF PLASMA PROTEINS AND THEIR FUNCTIONS

 Normal total plasma protein concentration: 6.4-8.3 gm/ dL of blood.

 Serum proteins means all plasma proteins minus fibrinogen.

Types Functions
Pre Albumin  Binds Thyroxine T3 T4
Albumin  Controls colloidal osmotic pressure
 Binding and Carrier protein: lt helps in transport of anions, cations,
dyes, drugs, hormones, fatty acids, metals, amino acids, enzymes
and bilirubin.
Globulin
Fibrinogen  Helps in blood clotting
Prothrombin  Helps in blood clotting

Forms of Globulin:

 Glycoprotein: Carbohydrate plus protein.

 Lipoprotein: α2-globulin plus lipid; it is a water-soluble complex with the following subtypes:
 High density lipoprotein (HDL) or α-lipoprotein. It contains 50% protein with large
amount of cholesterol and phospholipids.
 Low density lipoprotein(LDL) - contains large amount of glycerides.
 Very Low density lipoproteins (VLDL) : LDL and VLDL are also called 'β'-lipoprotein; they
have higher proportion of fat in the form of triglycerides or cholesterol.
 Chylomicrons - contain 2% protein and 98% triglycerides.
  HDL levels are increased in individuals who exercise and those who drink alcohol in
moderation, whereas they are decreased in smokers, obese and sedentary workers.
 In healthy individuals, proportion of HDL is high but in coronary artery disease (CAD) patients,
proportion of 'β'-lipoproteins (LDL and VLDL) increases.

 Lipoproteins are used in lipid metabolism and increase in: (a) Atherosclerosis, (b) Obesity and
(c) Liver diseases

 Transferrin: α2-β globulin (mainly β-globulin),

 It has the specific property of iron binding; each transferrin binds 2 atoms of ferric ions.
 Functions:
(i) regulates and controls iron absorption from GIT;
(ii) protects against iron intoxication;
(iii) helps in iron transport.

 Haptoglobins: α2 Globulin
 It forms stable complexes with free haemoglobin, therefore:
 prevents loss of iron through urinary excretion;
 protects the kidney from damage by haemoglobin;

 Ceruloplasmin: α2-β globulin (mainly α2-globulin),

 It binds with copper and helps in its transport and storage.

"WILSON'S DISEASE" - It is due to deficiency of ceruloplasmin, therefore, free copper increases in

circulation which gets deposited in brain and liver to cause their destruction (hepato-lenticular
degeneration); also copper is lost in urine.

 Feritin: present in foetus and newborns. It is a growth promoting protein.

 Coagulation factors: α, β globulin.
 Angiotensinogen: α2-globulin
 Haemagglutinins i.e. antibodies against red cell antigens.
 Immunoglobulin (lg): y-globulin.
VARIATIONS IN PLASMA PROTEIN CONCENTRATION

1. DECREASED PROTEIN (HYPOPROTEINAEMIA)

 Haemorrhage.
 Burns
 Pregnancy
 Malnutrition
 Starvation.

2. INCREASED PROTEIN (HYPERPROTEINAEMIA)

 This is because of loss of more water from the plasma e.g. secondary to extensive burns.
 Ddehydration and diabetes insipidus
 Hemolysis
 Leukaemia.

3. DECREASE IN ALBUMIN

Physiological

 Infancy and newborns (normal plasma protein level: 5.1-5.5 gm/dL) because of hepatic
immaturity.
 Pregnancy (during 1st six months). Globulin also decreases.

Pathological

Impaired protein synthesis due to:

 Hepatitis
 Cirrhosis of liver
 Chronic diseases
 Severe malnutrition and fasting causes poor supply of proteins
 Malabsorption

Excessive loss due to:

 Burns
 Nephrosis. It causes increased loss of albumin in urine.

4. INCREASE IN ALBUMIN

 Dehydration
 Congestive cardiac failure
5. INCREASE IN Y-GLOBULIN

 Multiple myeloma
 Tuberculosis
 Lymphatic leukaemia
 Cirrhosis of liver and Acute hepatitis.
 Nephritis

6. DECREASE IN Y-GLOBULIN

 Nephritis
 Hypogammaglobulinaemia

7. FIBRINOGEN

 Solely manufactured in the liver.

Decreases in
 congenital
 carcinoma prostate
 extensive cardiac or pulmonary surgery
 intra-vascular coagulation.

Increases in:
 pregnancy, menstruation
 malaria
 tissue injury
 acute or chronic infections

FUNCTIONS OF PLASMA PROTEINS

1. Helps in coagulation of blood due to presence of fibrinogen, prothrombin and other coagulation
factors which are protein in nature.

2. Helps to maintain colloidal osmotic pressure: (COP) across the capillary wall; normally it is 25-30
mmHg. How?

 Osmotic pressure across the capillary wall can be exerted both by (a) the crystalloids e.g.
urea,. Na+, glucose etc., and (b) the colloids e.g. plasma proteins.
 However, capillary wall is completely permeable to crystalloids, therefore, crystalloids hardly
contribute to capillary osmotic pressure and proteins exert an osmotic force of 25 mmHg across
the capillary wall.
 COP due to the plasma colloids is called the oncotic pressure
 COP is inversely proportional to the molecular size and shape, and is directly related to the
concentration of molecules. Therefore, 80% of COP is due to albumin because of least
molecular weight (i.e. molecule size) and maximum concentration
  COP across the capillary wall helps to maintain the exchange of fluid at tissue level. The rate
of fluid exchange (i.e. filtration-absorption) at any point along a capillary depends upon a
balance of forces, called Starling forces

(a) Hydrostatic pressure across capillary wall - it favours filtration.

(b) COP across capillary wall - it favours absorption.
(c) Hydrostatic pressure in interstitial fluid: Normal 2-3 mm.Hg.
(d) Interstitial fluid osmotic pressure: Normal 3-4 mmHg.

 (c) and (d) essentially cancel each other, therefore, forces which determine fluid exchange at
tissue level are · (a) and (b).
 Hydrostatic pressure at arteriolar end is 37 mmHg, therefore, some fluid is forced out of
capillary bed: 37 - 25 = 12 mmHg
 Hydrostatic pressure at venous end is 15 mmHg, therefore, some fluid will be pulled back by
osmotic forces: 25 - 15 = 10 mmHg.
Applied Physiology

 Hypoproteinemia (i.e. decrease in plasma protein level) causes decrease in COP, therefore,
increase filtration occurs at arterial end and decrease in absorption of fluid at venous end,
resulting in abnormal collection of fluid in interstitial spaces, called OEDEMA.
 When capillary permeability is increased e.g. in anoxia, urticaria, inflammation etc., all the
proteins escape much more readily from the capillary into interstitial spaces producing oedema

3. Helps in maintaining viscosity of blood. How?

 The viscosity of a protein depends on: (i) the shape of the protein molecules (mainly), and (ii)
the size of the protein molecules.
 The less symmetrical the molecule (like fibrinogen), the greater is its viscosity.
  Since 80% of total plasma protein concentration is due to albumin, and fibrinogen is present in
traces, blood viscosity is maintained at low level.
 Normally viscosity of blood is 4-5 times that of water.

4. Helps in maintaining systemic arterial blood pressure constant.

5. Provides stability to blood due to presence of globulin and fibrinogen. If blood loses its stability, it
will lead to Rouleaux formation of RBCs i.e. RBCs pile one over another.
6. Helps in maintaining the acid-base balance in the body.
8. Immune function. y-globulin produce antibodies which provide immunity to the body.
9. Transport function.
10. Reservoir function. Plasma proteins form loose bond with the hormones, drugs and metals etc. to
serve as a 'reservoir', from which the same are released slowly. This plays a beneficial role during
starvation.
ERYTHROCYTES
GENERAL STRUCTURE

 RBC is a circular, biconcave, non-nucleated disc.

Advantage of Biconcave shape

 Allows considerable alteration in cell volume. Thus, can withstand considerable
changes of osmotic pressure and resist hemolysis.
 Allows easy folding of RBC on itself when it passes through capillaries.

The mature RBC has no nucleus, no mitochondria and no ribosome, still it can live for 120 days and
can carry out its normal activities. How?

 RBC depends entirely on glucose metabolism for its energy supply.

 Glucose is transported easily across the cell membrane by facilitated diffusion (i.e.
carrier mediated passive process).
 Although the cell has no mitochondria but it has cytoplasmic enzymes for metabolizing
glucose and other substances and for utilization of oxygen.
 As these metabolic systems become progressively less active with time, it limits the life
span of RBC.

 Structure:
 RBC contains haemoglobin, which takes pink colour with Leishman's stain.
 Its cell membrane contains circular pores, which are concerned with ingress or egress
of water and electrolytes.
 Below the cell membrane is a contractile layer of lipoprotein- Spectrin, which is
arranged in a fibrillar manner. It maintains the shape and flexibility of RBC membrane
and also contains specific blood group substance, the antigen.

 Composition
 62.5% water
 35% Hemoglobin (29.5 ± 2.5 pg/ RBC)
 2.5%:
(a) Sugar - glucose
(b) Lipids - cephalin, cholesterol and lecithin
(c) Protein - Glutathione, albumin like insoluble
protein, acts as a reducing agent, thus
prevents damage of hemoglobin.
(d) Enzymes of glycolytic system; carbonic -
anhydrase and catalase.
(e) Vitamin derivatives,
(f) Ions - Na+, K+, Ca2+, PO4 3- and sot.

 Diameter: 6.5-8.8 µm (average 7.3 µm)

 Thickness: at periphery 2-2.4 µm; at the center 1.2-1.5 µm
  Volume: 78-94 µm3 or fL (86 ± 8 µm3)
 Count:
 At birth; 6-7 million/µL
 Adults - Male: 5-6 million/µL (average 5.5 million/µL)
 Females: 4.5-5.5 million/µL (average 4.8 million/µL)
 Clinically 5 million/µL is taken as 100% RBC count.

 Life span: 120 days;

 Site of Destruction: Tissue macrophage system

 Functions:

 That of hemoglobin
 Helps in identifying blood groups as it contains blood group specific substance i.e.
antigen on its surface.

VARIATIONS IN SIZE, SHAPE AND STRUCTURE OF RBC

 Anisocytosis - Variation in the size of RBCs.

 Poikilocytosis - Variation in the shape of RBCs.
 Spherocytosis - Spherical RBCs; more fragile.
 Anemia - Reduction in number of RBCs less than 4 million/µL or their content of hemoglobin
less than 12 gm/ dL or both.
 Polycythemia - RBC count increases more than 6 million/ µL.

Causes:

A. Physiological
 at birth
 at high altitude due to chronic hypoxia
B. Pathological
 congenital heart diseases which produces hypoxia
 dehydration
 shock
 tumor of bone marrow, called Polycythemia vera. In this condition RBC count may be
increased up to 7-8 million/ µL and is associated with presence of immature RBCs in
the peripheral blood.

 At Birth
 RBCs are larger in size and RBC count is 6-7 miillion/µL.
 PCV (packed cell volume) is 54%, because RBC: count is more.
 Reticulocytes are 2-6% of RBC count.
HAEMOPOIESIS
Definition: It is the development of blood cells i.e. RBCs., WBCs and platelets.
 Therefore, the term haemopoiesis includes:
1. Erythropoiesis i.e. development of RBCs
2. Leucopoiesis i.e. development of WBCs; and
3. Megakaryocytopoiesis i.e. development of platelets

ERYTHROPOIESIS

DURING INTRAUTERINE LIFE

3 stages

1. Mesoblastic stage: In early embryo upto 3 months of foetal life, RBCs are formed from
mesoderm of yolk sac.
 Since erythropoiesis occurs within the blood vessel, therefore, this stage is also called
intravasettlar erythropoiesis.

2. Hepatic Stage: After 3 months of foetal life, liver and spleen are the site of blood formation.
Nucleated RBCs develop from the mesenchyme between the blood vessels and the tissue cells.

3. Myloid Stage : From the middle of foetal life, erythropoiesis occurs in the bone marrow.

 Hepatic and myeloid stages are extravascular erythropoiesis

IN CHILDREN

 Erythropoiesis occurs in:

(1) All bones with red marrow (mainly),
(2) Liver,
(3) Spleen.

IN ADULTS

 i.e. after 18-20 years of age, from red bone marrow which includes:

 Ends of long bones like humerus and femur, because shaft is converted to yellow marrow;
 skull
 vertebrae
 ribs
  sternum
 pelvis
 If marrow gets destroyed, then liver and spleen again become important sites of blood
formation.

STAGES OF ERYTHROPOIESIS

 During the development of erythrocytes as the

cell attains maturity, it shows the following
characteristic features

1. Reduction in the cell size.

2. Cytoplasm increases in amount and

nucleus decreases in size.

3. Staining reaction of cytoplasm changes

from deep basophilic to polychromatophilic
(acidophilic plus basophilic) and finally to
acidophilic; due to gradual reduction in RNA
amount.

3. Initially, nucleus is very big in size with

open chromatin and containing many
nucleoli; with maturity of RBC, chromatin
material condenses and degenerates
finally leading to disappearance of nucleus
and nucleoli.
4. Hb appears in intermediate normoblast
5. Nuclease ejected from late normoblast
REGULATION OF ERYTHROPOIESIS

HYPOXIA

 Hypoxia means lack of oxygen at tissue level.

 It is the most potent stimulus for the production of RBCs.
 Hypoxia causes stimulation of bone marrow thereby increases RBC production.
 This effect is mediated by erythropoietin.
 Erythropoietin or Hemopoietin or Erythrocyte stimulating factor (ESF) or Erythropoiesis
stimulating hormone (ESH)

DIETARY FACTORS

 Proteins help in 'globin' formation.

 Iron, manganese, copper, cobalt, nickel help in 'haem' formation.
 Calcium increases iron absorption from GIT.
 Vitamins C, B12 and folic acid help in synthesis of nucleic acid

CASTLE’S INTRINSIC FACTOR

EXTRINSIC FACTOR
HAEM

 Haem is present in haemoglobin, myoglobin and cytochromes.

Cytochromes are components of ETC, which are required in all
cells of the body. So Haem is required in all cells of the body.

Heme as a Component of Important Structures

 Hemoglobin (transport oxygen)

 Myoglobin (stores oxygen)
 Cytochromes (in ETC and hydroxylation of xenobiotics)
 Enzymes:
 Catalase (degradation of Hydrogen Peroxide)
 Peroxidase (degradation of Hydrogen Peroxide)
 Guanylate Cyclase (stimulated by Nitric Oxide)
 Tryptophan Pyrrolase (oxidation of Tryptophan)

Structure

 Haem is a metalloporphyrin (Iron +

Protoporphyrin).
 Pyrrole rings are derived from Porphobilinogen
(PBG)
 4 Pyrrole rings = Porphyrin (cyclic structure)
 Porphyrin with attachment to 4 Methyl, 2 Propionyl
and 2 Vinyl groups = Protoporphyrin
 Protoporphyrin ring + Iron (Fe) in center = Heme
The side chain groups in porphyrins may be
arranged in four different structural configurations
(known as Porphyrin Type I to IV). Heme is Type III
Porphyrin.

HAEM SYNTHESIS

 Occurs in all cells of body. But Haem synthesis

does not occur in mature RBCs as they lack
mitochondria. 85 % of Haem synthesis occurs in
liver and erythroid tissues
 Compartment → both mitochondria and cytoplasm
(It starts from mitochondria)
 Starting material – Succinyl CoA and Glycine
 RLE – ALA Synthase. It requires Vitamin B6
(Pyridoxal Phosphate) as a cofactor
 It is repressed by haem.
PORPHYRIAS

 Porphyria is deficiency of one of the haem synthesis enzymes,

other than ALA-synthase
 ALA-Synthase I deficiency is lethal
 ALA-Synthase II deficiency is known as X-linked Sideroblastic
anemia (It is not a porphyria)

• Erythropoietin activates ALA synthase, So erythropoietin deficiency which occurs

in chronic renal failure, leads to anemia.
• Haem synthesis continues in liver cells according to metabolic needs. But in RBCs,
it is a one time event, so no rate limiting enzyme here.

 Lead poisoning is the most common cause of acquired

porphyria. Although iron deficiency is more common. But iron
deficiency leading to porphyria is a rare thing. But lead
poisoning will almost always lead to porphyria.
 HAEM CATABOLISM

 Site: Macrophages of reticuloendothelial system (Spleen, Bone

Marrow)

Steps of Haem Degradation

1. Formation of Bilirubin: Haem first gets broken down

and forms Biliverdin and then Bilirubin. Haemoxygenase
catalyze cleavage of Haem ring by NADPH- cytochrome
P450 reductase dependent oxidation of Haem to
Biliverdin, CO and free iron (a complex oxidation-
reduction reaction). This enzyme is also known as
NADPH: Ferrihemoprotein oxidoreductase.
2. Uptake of bilirubin by liver: Bilirubin is transported to liver via
blood. In blood, bilirubin is complexed with albumin.
3. Conjugation of bilirubin: Bilirubin is conjugated with two
molecules of glucuronic acid, making conjugated bilirubin
(bilirubin diglucuronide).
4. Fate of bilirubin: Bile is secreted from liver into the intestine.
In intestine, glucuronic acid is removed by bacteria. The
resultant bilirubin is converted to urobilinogen. Some of the
urobilinogen is reabsorbed from gut and enters portal
circulation. Some of this urobilinogen enters enterohepatic
recirculation and remaining enters kidneys via blood where it is
converted to urobilin, which is responsible for giving yellow
color to urine. Remaining urobilinogen in intestine is oxidized
by intestinal bacteria to form stercobilinogen, which gets
converted to stercobilin, giving stools its characteristic color.
ANAEMIAS

DEFINITION

 Anemia is a clinical condition characterized by reduction in the number of RBCs less than 4
million/ µL or their content of hemoglobin less than 12 gm/ dL or both.

GRADING

 Mild Anemia: Hemoglobin 8-12 gm/ dL

 Moderate Anemia: Hemoglobin 5-8 gm/ dL
 Severe Anemia: Hemoglobin less than 5 gm/ dL

CLASSIFICATION

ETIOLOGICAL

 This is based on the cause of anaemia.

HEMORRHAGIC

 Anaemia due to blood loss

(i) Acute i.e., sudden loss of blood

(ii) Chronic - slow loss of blood due to piles; worm infestation; peptic ulcer; during
menstruation etc.

DIETARY DEFICIENCY

due to iron, vitamins and proteins etc

DYSHEMOPOIESIS

 Causes:
(i) X-rays irradiations
(ii) (ii) y-rays irradiation
(iii) (iii) hypersensitivity of bone marrow to (a) cytotoxic drugs, sulpha drugs (b) chemicals.
HEMOLYTIC ANEMIAS

 Anemias due to excessive destruction of RBCs.

(i) Intrinsic (intra-corpuscular) defects

 Hereditary in nature:
(a) Congenital (or familial or hereditary) spherocytosis.
(b) Haemoglobinopathies - sickle cell anaemia and thalassaemia.
(c) Erythroblastosis foetalis.
(d) Glucose-6-phosphate dehydrogenase (G6PD) deficiency.

(ii) Extrinsic (extra-corpuscular) defects

 Acquired in nature:
(a) Antigen-antibody reaction.
(b) Infection e.g. malaria.
(c) Drugs/ poisons e.g. quinine, aspirin, burns, snake venom etc.
(d) Hypersplenism, it causes over activity of normal destructive mechanism.

MORPHOLOGICAL CLASSIFICATION.

 This is based on the size of RBC and its hemoglobin concentration.

PERNICIOUS ANAEMIA OR ADDISON'S ANAEMIA

 Pernicious means destructive or injurious.

CAUSE

 This is due to lack of intrinsic factor with a consequent failure in the absorption of vitamin B12.
The primary lesion is atrophy of gastric mucosa which contains oxyntic cells.

CHARACTERISTIC FEATURES

1) Bone Marrow

 Anaemia produces hypoxia which results in stimulation of erythropoiesis in bone marrow

with maturation arrest, therefore, bone marrow becomes hyperplastic and gets replaced
by:
 (i) 70% proerythroblasts and early normoblasts (normal: 30%), and
 (ii) 30% intermediate and late normoblasts (normal: 70%) This over activity of bone marrow
is called Megaloblastic hyperplasia of bone marrow.

2) Blood Changes

i. RBC: Macrocytic normochromic

 Count decreases markedly; less than 1 million/µL
 Haemoglobin content decreases less than 12 gm/dL
 Diameter increases
 MCV increases
 MCH increases
 MCHC usually normal
 Peripheral smear shows nucleated RBCs with marked anisocytosis and
poikilocytosis.
 Reticulocyte count increases more than 5% (normal less than 1%).
 Excessive destruction of RBCs in spleen, liver and bone marrow produces:
 Decrease in life span of RBCs;
 serum bilirubin increases more than 1 mg/ dL (normal 0.2-0.8 mg/ dL), this
produces low grade hemolytic jaundice and increased urine urobilinogen
excretion;
 increase serum iron (normal 60-160 µg/dL), because iron is not utilized by
immature RBCs.

ii. WBCs and platelets both decrease because encroachment of megaloblastic tissue on
the space available in the bone marrow.
 3) Changes in GIT
 Deficiency of intrinsic factor
 Atrophy and destruction of gastric mucosa containing oxyntic cells produces marked or
complete lack of HCI in gastric juke (Achlorhydria).
 Soreness and inflammation of the tongue.
 Loss of appetite and apathy (mental laziness).
 Diarrhoea.

4) Changes in nervous system

 In advanced cases demyelination of white fibres of the spinal cord occurs, affecting the
dorsal (posterior) columns chiefly; and later the lateral columns, called Subacute Combined
Degeneration of Spinal Cord.
 This is associated with tingling and numbness in hands and feet; motor and psychological
disturbances.

5) Laboratory investigations

 Plasma concentration of vitamin B12 decreases to 1/10th of normal (normal: 300-400

pg/ml).
 Vitamin B12 excretion in feces increases to 90% (normal: 30-40%).
 Urinary excretion of vitamin B12 decreases, because of poor absorption of vitamin B12 from
intestine and its low plasma levels.

SIGNS OF IMPROVEMENT AFTER BEGINNING TREATMENT WITH VITAMIN B12

 Reticulocyte response
 Normoblastic reaction
 bilirubin returns to normal.
 Increase in WBC and platelet count
 patient feels stronger

FOLIC ACID DEFICIENCY ANAEMIA

 Folic acid deficiency also produces Megaloblastic anaemia as seen with vitamin B12 deficiency,
except that neuropathy occurs only with Vitamin B12 deficiency.

CAUSES OF FOLIC ACID DEFICIENCY

1. Less dietary intake.

2. Poor absorption
3. Increased demand e.g. pregnancy.
4. Antifolate drugs e.g. anti-cancer drugs (methotrexate).
IRON DEFICIENCY ANAEMIA

 Commonest anaemia in India.

DEFINITION

 Any anaemia which responds to adequate dosage of iron is called iron deficiency anaemia.

CAUSES

1. Decrease intake - milk fed infants.

2. Increased loss: (i) Acute haemorrhage (ii) Chronic haemorrhage: worm infestation, peptic
ulcer, piles, increased menstrual blood loss etc.
3. Increased demand: Infancy, childhood, pregnancy, menstruation.
4. Defective utilization due to decreased absorption in diseases of stomach and duodenum.

CHARACTERISTIC FEATURES

1. RBC - Microcytic hypochromic

(i) Count decreases or normal
(ii) MCV, MCH, MCHC and CI decrease.
(iii) Life span - normal.
(iv) Peripheral smear shows anisocytosis and poikilocytosis.

2. Bone Marrow - Normoblastic hyperplasia

3. WBC and platelets - normal
4. Investigations
(i) Serum Ferritin decreases
(ii) Serum iron decreases (normal: 60-160 µgm/dL)
(iii) Total iron binding capacity (TIBC) - increases (normal: 150-350 µgm/ dL).

5. Nails-dry, soft, spoon shaped; later develop longitudinal striations.

6. Tongue - angry red.
7. Cardiovascular/ Respiratory System - Early breathlessness; palpitations; repeated chest
infections.
8. Nervous Sysem - Irritability; loss of concentration; headache; generalized body ache;
impotence.
LEUCOCYTES
A. Granulocytes

 i.e. WBC with granules in their cytoplasm Percentage

 1. Neutrophils 50-70 %, 3000-6000 / μl
 2. Eosinophils 1-4 %, 150-300 / μl
 3. Basophils <1 %, 10-100/ μl

B. Agranulocytes

 1. Lymphocytes 20-40%, 1500-2700 / μl

 2. Monocytes 2-8%, 300-600 / μl

 Total Leucocyte Count (TLC)

 At birth : 20,000/µL; count decreases after 2nd week, reaching normal adult value at 5-10
years.
 In adults : 4,000-11,000/µL.

Leucopenia

 TLC decreases less than 4000/ µL.

 Causes
1. Starvation
2. Typhoid (enteric) fever
3. Viral or protozoal infection
4. Bone marrow depression.

Leucocytosis

 TLC increases above 11,000/ µL.

 Causes
1. Newborn (normal - 20,000/ µL)
2. In the evening (Note: minimum count is seen in the morning)
3. Exercise
4. Stress
5. Pregnancy,
6. Any pyogenic (acute/ chronic pus forming) or pyrogenic (fever producing) infection.

Leukaemia is a cancerous condition of blood in with TLC is usually more than 50,000/ µL and
associated with presence of immature WBCs in the peripheral smear.
STRUCTURE, FUNCTIONS

NEUTROPHIL/POLYMORPHONUCLEAR LEUCOCYTE

 Size: 10-14 µm diameter

 Nucleus
(i) Purple in colour.
(ii) Multilobed (1-6 lobes), that is why also called
polymorphonuclear leucocyte.
(iii) Young cells have single 'horse shoe shape' nucleus.
(iv) As the cells grow older nucleus becomes
multilobed. Lobes are connected with one another
by chromatin threads. More the number of lobes,
the more mature is the neutrophil.
 Cytoplasm: Slight bluish in colour, granular.
 Life span: 6-30 hours
 Functions:

1. Phagocytosis -whenever the body gets invaded by bacteria, neutrophils are the first cells to
seek out to ingest and kill the bacteria. They have been thus called the body's ,first line
defence against bacterial infections.

2. They contain a fever-producing substance, endogenous pyrogen which is an important

mediator of febrile response to bacterial pyrogens.

EOSINOPHIL

 Size: 10-14 µm diameter

 Nucleus:
(i) Purple colour .
(ii) Usually (85%) cells - 'bilobed', the two lobes are
connected with chromatin thread thus producing
'spectacle' appearance.
(iii) Remaining 15% cells have 'trilobed' nucleus.
 Cytoplasm:
(i) Acidophilic, therefore, appears light pink in
colour.
(ii) Granular.

 Functions

1. Mild phagocytosis because less motile than neutrophils.

2. Allergic reactions
3. They enter the tissues and are specially abundant in the mucosa of respiratory tract,
gastrointestinal and urinary tract, where they provide local mucosal immunity.
4. Eosinophils attack parasites that are too large to be engulfed by phagocytosis. Eosinophil
granules release chemicals (peroxidase) which are toxic to larvae of parasites.
 BASOPHIL

 10-14 µm diameter
 Nucleus As in Eosinophil.
 Cytoplasm : Slight basophilic, therefore, appears blue; granular.
 Functions
1. Mild phagocytosis.
2. Allergy – Histamine
3. Heparin

LYMPHOCYTES

1. Large lymphocytes: 10-14 µm diameter; precursor of small

lymphocytes.
2. Small lymphocytes (B-type): 7-10 µm diameter; responsible
for 'antibody' production.Both large and small lymphocytes
have the same structure.

 Nucleus
(i) Single; very big; purple in colour.
(ii) (ii) Shape: round, oval
(iii) Central in position and occupies whole of the cell leaving marginal cytoplasm at one end of
it or all around it.

 Cytoplasm
(i) Pale blue
(ii) Scanty, its amount is always less than the amount of the nucleus.

 Functions : Produce antibodies, Cytotoxic

MONOCYTE-LARGEST WBC

 Size: 10-18 µm diameter with irregular cell outline.

 Nucleus:
(i) Pale staining.
(ii) Single.
(iii) Round or indented (kidney shaped).
(iv) Eccentric in position i.e. present on one side of the cell.
(v) Nuclear chromatin is finely reticular.

 Cytoplasm : Usually pale blue; clear.

  Functions

1. Active phagocytosis. Monocytes follow the neutrophils in the areas of infections or inflammation and
constitute a second line defence. Phagocytic mechanism is the same as seen in neutrophils.
2. Monocytes enter the circulation from bone marrow but after 72 hours they enter the tissues to
become 'tissue macrophages'. All tissue macrophages come from circulating monocytes.

Life span: Approx. 3 months

3. Monocytes may also kill tumour cells after sensitization by lymphocytes.

4. They synthesize complement and other biologically important substances like prostaglandin E and
clot promoting factors.

LEUCOPOIESIS
HEMOSTASIS

DEFINITION

Spontaneous arrest or prevention of bleeding by physiological processes is called haemostasis.

MECHANISM OF HAEMOSTASIS

Injury to vessel wall Formation of clot Seals off the damaged blood vessel

prevents further loss of blood

Three major events which get involved during haemostasis are:

1. Constriction of injured blood vessel due to

I. local myogenic contraction of the blood vessel
II. nervous reflexes that originate from injured tissues;
III. release of 5-HT and other vasoconstrictor substances from the platelets

2. Formation of a temporary haemostatic plug of platelets.

3. Conversion of temporary haemostatic plug into the definitive haemostatic clot.

PHYSIOLOGY OF CLOTTING MECHANISM

BLOOD BANKING AND TRANSFUSION MEDICINE.

BLOOD GROUPS.

 They are the glycoproteins present on the surface of Rbcs.

 39 blood group systems exist.
 Major blood group system - ABO and RH system.- Most used.
 Discovered by Landsteiner.
 Minor blood group system.- Kell, Duffy, Kidd, MNS
 ABO and RH systems follow Co dominance, meaning both will be expressed
concomitantly whenever they are present.
 Difference between ABO and RH system:

ABO system RH system.

 Gene on chromosome 9.  Gene on chromosome one.

 Expressed as A,B,AB,O  Expressed as positive or negative.

 Present in saliva, semen and sweat.  Not present.

 IgM naturally occurring.  IgG do not occur naturally.

 FORMATION OF A, B, O BLOOD GROUPS.

Gene on chromosome 19

Produces H substance.

Activates chromosome 9.

A substance B Substance No substance Both A and B

substance.

A product B products No product

attache to H. Both A and B
attaches to H attached to H
attaches to H.
B
A O
AB

 Homozygous mutations of chromosome 19 produce no H substance: Bombay Blood

Group.
BLOOD GROUPING ANALYSIS.

 Forward grouping: Test for presence of antigens on RBC surface.

 Reverse grouping: Test for presence of antibodies inpatients plasma.

Procedure:

 Take a glass slide.

 Put 3 drops of blood.
 Add Anti A, Anti B and Anti D
to each drop.
 If antigen is present,
agglutination occurs.

 O positive. - Most common drug group in India.

Bombay blood group:

 Person lacs H substance.

 No Antigens to H, A, B.
 Antibodies with A, B & H present.
 This blood can be transfused to anyone.
 But people with Bombay Blood group cannot be transfused with a B or O blood.

Blood banking:

 1st October: Blood donation day.

Blood Bag:

 Volume of one blood bag: 350 ml.

  Triple bag- To make components like packed RBCS, platelets. Volume: 450 ml.

ANTICOAGULANT IN BLOOD BAG

 ACD: Acid, citrate, dextrose: 21 days.

 CPD: Citrate phosphate, dextrose: 21 days.
 CPD A: Citrate Phosphate dextrose adenine: 35 days.
 SAGM: Sodium adenine glucose Mannitol: 42 days. Longest shelf life.

 Shelf Life: The duration for which the stored blood products remain good and
transfusable. If exceeds self life, the blood product is expired and shouldn't be
transfused. It depends on the anticoagulant present.

Functions of the anticoagulants:

 Citrate: Anticoagulant by chelating Belgium.

 Phosphate: Act as buffer and helps in maintaining pH.
 Dextrose: provides nutrition.
 Add an in: Provide substrate for ATP synthesis. Increased self life.

Features of a blood bag:

 Anticoagulant is written - CPDA

 Volume- 350 ml.
 Date of collection:
 Date of expiry:
  After collecting blood from the donor, it must be screened for 5 infections before it
can be transfused.
 5 diseases: HIV, Hepatitis B, Hepatitis C, Malaria, Syphilis.
 Hepatitis C- most common transfusion transmitted infection.
 Malaria can be transmitted by all blood products.

COMPONENTS OF BLOOD.

 From whole blood components must be separated within 6 hours of blood

collection.

Blood product. Volume. Temperature. Shelf life. Use.

Pecked RBC. 350 ml. 2 to 60 C CPDA: 35 days. Severe anemia.

SAGM: 42 days. One unit is equal to 1 gram % Hb or 3% hematocrit.

Fresh frozen plasma/ FFP. 200 ml. <-30 0C 1 year. Multiple coagulation factor deficiencies. DIC. Chronic
liver disease. Hemophilia B.

Deficient in factor 5 and 8.

Cryoprecipitate: Centrifuge 10 to 20 ml. < -30 0C 1 year. Factor 13 deficiency. Hemophilia A. Hypo
FFP. Fibrinogenemia. Von Willebrand’s disease.

Rich in factor 8, 13, von

Willebrand factor and
fibrinogen.

Platelet rich plasma: Platelet defects. Thrombo cytopenia.

2 types:
Random donor platelets. 1 unit RDP =10,000 cells/cu.mm.
50 to 70 ml. Room temp./ 5 days.
20-240C With
agitation to prevent
clumps.

Single donor platelet.

20- 24oC With

200 to 300 ml. agitation. 5 days. 1 unit SDP =
3-50,000 cells/cu.mm.
Random donor platelets (RDP):

 Blood taken from different individuals, centrifuged and PRP produced and transfused.

Single donor platelets (SDP):

 Platelets taken from a single person by apheresis. Much more effective and expensive.

Advantage of RDP over SDP:

 RDP can be used to make other Blood components as well.

 Life span of transfused RBCs - 50 to 60 days.

 Product which is most susceptible to bacterial contamination: Platelets.

Transfusion protocols:

 Do not transfuse blood immediately after retrieving it from its storage at cold
temperature.
 Patient will develop hypothermia.
 Warm or thaw it before transfusing.
 Transfusion should commence within 30 minutes of taking the product out of Fridge.
 Transfusion should be finished within 4 hours.
 Size of micropore filter – 170 microns.
 Size of needle used – 18-19 G.
BLOOD TRANSFUSION REACTION:

Two types:

IMMEDIATE DELAYED
 Allergies.  Graft versus host disease (GVHD).
 Febrile non hemolytic transfusion  Delayed hemolytic transfusion
reaction (FNHTR): M/C. Prevent by reaction.
using Leuko depleted blood  Post transfusion purpura.
products.  Infections.
 Febrile hemolytic blood transfusion
reaction.
 TRALI - Transfusion related acute
lung injury.

MASSIVE BLOOD TRANSFUSION (MBT):

 Definition: Transfusion/ Replacement of patient’s whole blood volume within 24

hours. 5L (approximately 15 to 20 units).
 Ratio of RBC: FFP: Platelets - 1:1:1

Complications:

 Mnemonic – CATCH.
 Coagulopathies: Disseminated intravascular coagulation (DIC).
 Alkalosis: Metabolic Alkalosis due to formation of HCO3-.
 T: Hypothermia.
 C: Citrate toxicity. Manifest as tingling, numbness.
 H: Hyperkalemia (due to lysis of RBCs) leading to arrhythmia, hypocalcemia.
 M/C cause of death following MBT: DIC due to Coagulopathy.

TRALI:

 Transfusion Related Acute Lung Injury (TRALI).

 Definition: Development of fever, dyspnea, respiratory.
 Symptoms within 6 hours of blood transfusion.
 M/C cause of death due to blood transfusion.
 Usually occurs due to antibodies against HLA 2 or anti neutrophilic antibodies.
 More common with plasma products like FFP.
Differential diagnosis:

 ARDS/TRALI: In both conditions, chest xray shows bilateral pulmonary

infiltrates/white out appearance.
 TACO/TRALI: Blood pressure is high in TACO.
 (TACO: Transfusion Associated Circulatory Overload).
IMMUNITY
 First line of defense: Skin, epithelial linings.
 Second line of defense.

 The responses of the immune system: Humoral and Cellular (cell mediated).
 The Humoral responses are affected by elements free in the serum or body fluids; whereas cell
mediated responses involve cells directly eliminating the invading organisms.
THE NATURAL (OR INNATE) IMMUNE SYSTEM

A. NATURAL HUMORAL RESPONSES

1. The complement system

2. C-reactive protein
3. Interferons
4. Natural killer cells

I. COMPLEMENT SYSTEM

II. C-REACTIVE PROTEIN

III. INTERFERONS

IV. NATURAL KILLER CELLS (NK CELLS)

B. NATURAL CELLULAR RESPONSES

 circulating phagocytes: neutrophils and monocytes

THE ACQUIRED IMMUNE SYSTEM

ACQUIRED HUMORAL RESPONSES

ACQUIRED CELLULAR RESPONSES

 Cellular immunity is mediated by T8-cells.

 These cells are activated:
(i) when they are presented with antigens and MHC-I proteins on the surfaces of antigen-
presenting cells;
(ii) when exposed to interleukin-2 (IL-2).
 T-lymphocytes proliferate and differentiate into cytotoxic-T cells in about 2 weeks time.
 T-cells attack and destroy cells that have the antigen which activated them i.e. highly specific
immune reaction.
 They kill by inserting pore forming molecules (perforins) in the membranes of their target cells.