1. Physiology of erythrocytes Blood groups

2. Blood Cells RBCs, Red blood cells or erythrocytes
WBCs, white blood cells or Leukocytes
Platelets (thromobocytes)

3. Erythrocytes Cell Type Description Cells/mm3 (µl) of blood Function
Erythrocytes (Red blood cells, RBCs)
Description
Bicancavae, anucleate disc, salmon-colored, sacs of hemoglobin,most organelles ejected, diameter 7-8 µm
Cells/mm3 (µl) of blood
4-6 millions
Duration of development (D) & Life Span (LS)
D: 5-7 days
LS: days
Function
Transport oxygen bound to hemoglobin and also small amount of CO2

4. Erythrocytes (RBCs)
Red, oxygen carrying, hemoglobin containing, non-nucleated cells, present in the blood
Shape  Bi-concave Discs
Size:
Diam  µm
Thickness:
Thickest  2.5 µm
Thinnest  1 µm or <1 µm
Thin centers appear lighter in colour than edges
Volume: µm3
Life Span:
Adults: Days
Neonates: Days
Count:
Males: 5.2 million + 3,00,000 cells/mm3
Females: 4.7 million + 3,00,000 cells/mm3
Newborn: 6 – 6.5 million cells/mm3
Fetus: 7.8 million cells/mm3
Why count is different? 1
1- Males: Testosteron from leyding cells of testes, Increased BMR, increased oxygen demand, causes tissue hypoxia (low oxygen), this results in increased Erythropoietin release from kidneys (90%) (Juxta glumerular cells or mesangial cells) and liver (10%). Increased EPO, increased proerythroblasts formation from stem cells so increased RBCs.
Females: Less testosteron so less RBCs.
Infants: Greater need of oxygen as all their tissues are under a rapid growing process.

5. Leukocytes (lecuko- white) (White blood cells, WBCs)
Leuckocytes
Cell Type
Leukocytes (lecuko- white) (White blood cells, WBCs)
Description
Spherical, nucleated cells
Cells/mm3 (µl) of blood
,800
Types
Granulocytes
Neutrophils
Eosinophils
Basophils
Agranulocytes
Lymohocytes
Monocytes

6. Platelets (Thrombocytes)
Not cells
Cytoplasmic fragments of extraordinary large cells (60µm)  Megakaryocytes
Cytoplasm stain blue, granules Stain Purple
Essential for the clotting process when blood vessels are ruptured or their lining is injured.
Components of Granules
Serotonin
Ca 2+
Different Enzymes
ADP
Platelets derived Growth Factors (PDGF)
When not involved in clotting mechanism, they are kept inactive by molecules (NO, PG I2) secreted by endothelial cells lining blood vessels.

7. Hematopoiesis Process occurs in Red bone marrow
Hematopoiesis or hemopoiesis (Hemato, hemo = blood, Poiesis = to make)
Process occurs in Red bone marrow
Red bone marrow composition
It is composed of a soft network of reticular connective tissue bordering on wide blood capillaries called blood sinusoids. With in this network are immature red blood cells, fat cells, reticular cells ( secrete the fibers).
On average, the marrow produces 1 ounce of new blood every day
Cells produced are about 100 billion
All cells arise from the same type of stem cells the PHSC or hemocytobalsts (Cyte = cell , blast = bud) that reside in red bone marrow.
But the maturation pathway is different form each other, once a cell is committed to a specific blood cell pathway, it can not change
This commitment is signaled by appearance of membrane surface receptors that respond to specific hormones or growth factors, which in turn push the cell towards further specialization.

8. Erythrocytes (RBCs) Composition of RBCs:
The composition of RBCs is same as that of a normal cell except that mature RBCs contain Hb and don’t contain nucleus, mitochondria, and other important organelles.
Water = 65 %
Solid and semisolids = 35 %
Hb (33 %)
Organic and inorganic substances (2%)
(Amino Acids, Cholesterol, Creatinine, Proteins, Phospholipids, Urea)
How RBCs Change and Maintain Shape:
Main protein – Hb - 97 %
Other Proteins
Anti-Oxidant Enzymes (Get rid body of harmful O2 radicals)
Maintenance proteins
Bi-concave shape of RBCs is maintained by network of proteins, especially one called spectrin, it is attached to the cytoplasmic side of the plasma membrane, as spectrin net is deformable, it gives erythrocytes the flexibility to change their shape as necessary- to twist, turn and become cup shaped when pass through small capillaries – and then resume their normal shape.

9. Erythrocytes (RBCs) Energy Production:
For energy RBCs depend on plasma glucose, metabolic break down takes place through
Embden Meyerhof Glcolytic pathway
Pentose phosphate Pathway (PPP) or (Hexose Monophosphate shunt)
Structural Characterstics VS Function
Small size and Biconcave shape provides huge surface area (about 30 % more area than comparable spherical cells).
Excluding water content RBC is 97 % Hb that transports resp. gases.
Don’t use oxygen themselves as produce energy by anaerobic mechanisms.
Functions or RBCs:
O2 Transport:
Contains Hb, that carries oxygen bound to ‘Heme’ portion
CO2 Transport:
CO2 Transport takes place in combination with ‘globin’ protion. (20%)
Acid-Base balance
By buffering action of Hb
Blood Viscosity
Ionic balance

10. Factor needed of Erythropoiesis
Erythropoietin ( Released in response to Hypoxia)
Vitamin B 6 (Pyridoxine)
Vitamin B 9 (Folic Acid)
Vitamin B 12 (Cobolamin)
Essential for DNA synthesis and RBC maturation
Vitamin C  Helps in iron absorption (Fe+++  Fe++)
Proteins  Amino Acids for globin synthesis
Iron & copper  Heme synthesis
Intrinsic factor  Absorption of Vit B 12
Hormones
Physiological Variations in RBC count
Diurnal Variation (During 24 hours)
5 %
Lowest - Sleep and early morning hours
Highest - Evening
Temperature
High Altitude
Hypoxia
Radiations
X-rays
Water soluble vitamins 1-Vitamin C (Ascorbic Acid)
B1 (Thiamine), B2 (Riboflavin), B3 (Niacinamide, Niacin), B5 (Pantothenic acid), B6 (Pyridoxine), B7 (Biotin), B9 (Folic Acid (Folate)
B12 (Cobolamine),

11. Fate and destruction of RBCs 1
Anucleate  certain limitations.
No synthesis of new proteins, No growth, No division.
However they do have Cytoplasmic enzymes (hexokinase, Glu-6-phosphate dehydrogenase) that are capable of metabolizing glucose and forming small amounts of ATP. These enzymes also perform following actions
maintain pliability of the cell membrane,
maintain membrane transport of ions,
keep the iron of the cells’ hemoglobin in the ferrous form rather than ferric
Prevent oxidation of the proteins in the red cells.
Erythrocytes become “old” as they lose their flexibility and become pikilocytes (spherical), increasingly rigid and fragile. Once the cell become fragile, they easily destruct during passage through tight circulation spots, especially in spleen, where the intra-capillary space is about 3 micron as compared to 8 micron of cell size
RBCs useful life span is 100 to 120 days,After which they become trapped and fragment in smaller circulatory channels, particularly in those of the spleen. For this reason, the spleen is sometimes called the “red blood cell graveyard.”
Dying erythrocytes are engulfed and destroyed by macrophages.
1 -The heme of their hemoglobin is split off from globin. Its core of iron is salvaged, bound to protein (as ferritin or hemosiderin), and stored for reuse. The balance of the heme group is degraded to bilirubin (bil″i-roo′bin), a yellow pigment that is released to the blood and binds to albumin for transport.
Bilirubin is picked up by liver cells, which in turn secrete it (in bile) into the intestine, where it is metabolized to urobilinogen.
Most of this degraded pigment leaves the body in feces, as a brown pigment called stercobilin.
The protein (globin) part of hemoglobin is metabolized or broken down to amino acids, which are released to the circulation.
Disposal of hemoglobin spilled from red blood cells to the blood (as occurs in sickle-cell anemia or hemorrhagic anemia) takes a similar but much more rapid course to avoid toxic buildup of iron in blood.
Released hemoglobin is captured by the plasma protein haptoglobin and the complex is phagocytized by macrophages.

12. Regulation of RBCs production
Control of rate of erythropoiesis is based on ability of RBCs to transport sufficient oxygen to tissues as per demand, not the number
Tissue Oxygenation
Drop in normal blood oxygen levels may result due to
Reduced number of RBCs
Hemorrhage
Excess RBC Destruction
Reduced Availability of Oxygen
High Altitude
Lung Diseases
Increase Tissue demands of Oxygen
Aerobic Exercises
Erythropoietin (Formation & role)1
Glycoprotein, Mol wt= 34,000.
Erythropoietin, a hormone, produced mainly by the kidneys(90%) and also by liver(10%), stimulates erythropoiesis  by  acting  on committed stem cells to induce proliferation and differentiation of erythrocytes in bone marrow.
Site of Action: BONE Marrow
1- Hemostatic Imbalance: Rnal dialysis (Low EPO)
Athletes Doping: 45%-65% , so blood becomes Thick, sticky sludge that can cause clotting, stroke, heart failure. Dehydration

13. Regulation of RBC production
A negative Feed back mechanism

14. Hemoglobin (Hb) Red, oxygen carrying pigment present in RBCs. Quantity
Heme (4%)
Globin (96%)
Quantity
g in body
29-32 peco gram/RBC
RBCs
Male= 36g/100ml
Female = 34g/100ml
Whole Blood
Newborn = 14-20g/100ml
Male= 14-16g/100ml
Female = 12-14g/100ml
Molecular Weight
64,450
Types
4 types of poly peptide chains based on amino acid composition and sequence.
alpha, beta, gamma, delta
Adult Hb
Hb A = 2 alpha (141 AA)+ 2 beta (146 AA) chains (α2β2 )
Hb A2 = 2 alpha (141 AA)+ 2 delta (146 AA) chains (2.5%) 1 (α2δ2) (10 AA differ)
Fetal Hb
Hb F = 2 alpha (141 AA)+ 2 gamma (146 AA) chains 2 ( α2γ2) (37 AA differ)
99% replaced with adult Hb with in a year of birth.
1- 10 AA of delta chain are different from beta chain.
2- 37 AA of gamma chain are different from beta chain in sequence. And has less positive charges as compared to beta chain so less reaction with 2,3-BPG or DPG.
2,3-bisphosphoglycerate reacts with Hb in adults and reduces its binding affinity to O2
Fetal hemoglobin's affinity for oxygen is substantially greater than that of adult hemoglobin. Notably, the P50 value for fetal hemoglobin (i.e., the partial pressure of oxygen at which the protein is 50% saturated; lower values indicate greater affinity) is roughly 19 mmHg, whereas adult hemoglobin has a value of approximately 26.8 mmHg. As a result, the so-called "oxygen saturation curve", which plots percent saturation vs. pO2, is left-shifted for fetal hemoglobin in comparison to the same curve in adult hemoglobin.

15. Hemoglobin (Hb) 250 million Hb molecules / RBC
So carry 1 billion oxygen molecules / RBC
Synthesis of Hb
Starts at proerythroblastic stage
Synthesis steps:
Heme is made from acetic acid and glycine in mitochondria
Acetic Acid  α-ketoglutaric Acid  Succinyl Co A (Krebs Cycle)
Globin (polypeptide chain) is synthesized by Ribosomes
Reactions of Hb:
Oxyhemoglobin (oxygen + Hb) Ruby Red (in lungs) (Co-ordination bonds)
Deoxyhemoglobin (Reduced Hb) Dark Red (in tissues)
Carbaminohemoglobin (Co2 + Hb) (Globin’s amino acids) (20 %)
Caroboxyhemoglobin (Co + Hb)
Methemoglobin (Fe+++ instead of Fe++)
There are small amounts of hemoglobin A derivatives closely associated with hemoglobin A that represent glycated hemoglobins. One of these, hemoglobin A1c (HbA1c), has a glucose attached to the terminal valine in each β chain and is of special interest because the quantity in the blood increases in poorly controlled diabetes mellitus

16. Reactions of Hb:
Hemoglobin binds O2 to form oxyhemoglobin, O2 attaching to the Fe2+ in the heme. The affinity of hemoglobin for O2 is affected by
pH,
Temperature,
The concentration of 2,3-diphosphoglycerate (2,3-DPG) in the red cells.
2,3-DPG and H+ compete with O2 for binding to deoxygenated hemoglobin, decreasing the affinity of hemoglobin for O2 by shifting the positions of the four peptide chains (quaternary structure).
Each of the four iron atoms can bind reversibly to one O2 molecule. The iron stays in the ferrous state, so that the reaction is an oxygenation, not an oxidation. It has been customary to write the reaction of hemoglobin with O2 as
Hb + O2 ↔ HbO2
Since it contains four Hb units, the hemoglobin molecule can also be represented as Hb4, and it actually reacts with four molecules of O2 to form Hb4O8 as following.
The reaction is rapid, requiring less than 0.01 s.
The deoxygenation (reduction) of Hb4O8 is also very rapid.
2,3-bisphosphoglycerate reacts with Hb in adults and reduces its binding affinity to O2
Fetal hemoglobin's affinity for oxygen is substantially greater than that of adult hemoglobin. Notably, the P50 value for fetal hemoglobin (i.e., the partial pressure of oxygen at which the protein is 50% saturated; lower values indicate greater affinity) is roughly 19 mmHg, whereas adult hemoglobin has a value of approximately 26.8 mmHg. As a result, the so-called "oxygen saturation curve", which plots percent saturation vs. pO2, is left-shifted for fetal hemoglobin in comparison to the same curve in adult hemoglobin.

17. Hb Abnormalities Globin Genes1 determine the AA sequence in Hb.
Two types of Abnormalities:
Hemoglobinopathy
Abnormal polypeptide chains are produced
Sickle cell disease due to Hb-S
Thalassemia
In which the chains are normal in structure but produced in decreased amounts or absent because of defects in the regulatory portion of the globin genes.
The α and β thalassemias are defined by decreased or absent α and β polypeptides, respectively.
1000 Abnormal Hbs due to mutant genes in humans. usually identified by letter—Hb-C, E, I, J, S, etc.
Mostly, the abnormal Hbs differ from normal Hb-A in the structure of the polypeptide chains.
For example, In hemoglobin S,
α chains normal
β chains abnormal, among the 146 AA residues in each β polypeptide chain, one glutamic acid residue has been replaced by a valine residue.
1-There are two copies of the α globin gene on human chromosome 16. In addition, there are five globin genes in tandem on chromosome 11 that encode β, γ, δ (Delta), ζ (zeeta), ε (epsilon) globin chains

18. Hb Abnormalities
Heterozygous Half the circulating hemoglobin is abnormal and half is normal.
Have sickle cell trait
Homozygous  all of the hemoglobin is abnormal.
Develop the full blown disease
Results of abnormality
Many of the abnormal hemoglobins are harmless.
Abnormal O2 equilibriums.
Anemia.
Hb-S polymerizes at low O2 tensions, and this causes the red cells to become sickle-shaped, hemolyze, and form aggregates that block blood vessels.
The result is the severe hemolytic anemia known as sickle cell anemia.
The sickle cell gene is an example of a gene that has persisted and spread in the population.
It originated in the black population in Africa, and it confers resistance to one type of malaria.
Africa = 40% of the black population have the sickle cell trait.
In United States 10 %
Treatment:
Bone marrow Transplatation
Hb-F production by hydroxyurea.
When an abnormal gene inherited from one parent, when the individual is heterozygous—half the circulating hemoglobin is abnormal and half is normal.
When identical abnormal genes are inherited from both parents,  homozygous all of the hemoglobin is abnormal.
Many of the abnormal hemoglobins are harmless.
However, some have abnormal O2 equilibriums. Others cause anemia. For example, hemoglobin S polymerizes at low O2 tensions, and this causes the red cells to become sickle-shaped, hemolyze, and form aggregates that block blood vessels. The result is the severe hemolytic anemia known as sickle cell anemia. Heterozygous individuals have the sickle cell trait and rarely have severe symptoms, but homozygous individuals develop the full-blown disease. The sickle cell gene is an example of a gene that has persisted and spread in the population. It originated in the black population in Africa, and it confers resistance to one type of malaria. This is an important benefit in Africa, and in some parts of Africa 40% of the population have the sickle cell trait. In the United States black population its incidence is about 10%. Hemoglobin F has the ability to decrease the polymerization of deoxygenated hemoglobin S, and hydroxyurea causes hemoglobin F to be produced in children and adults. It has proved to be a very valuable agent for the treatment of sickle cell disease. In patients with severe sickle cell disease, bone marrow transplantation has been carried out and the patients have generally done well, though more study is needed.

19. Hemoglobin Metabolism
The heme of the hemoglobin is split off from globin.
Its core of iron is saved, bound to protein (as ferritin or hemosiderin), and stored for reuse.
The heme is converted to biliverdin. In humans, most of the biliverdin is converted to bilirubin, a yellow pigment that is released to the blood and binds to albumin for transport.
Bilirubin is picked up by liver cells, which in turn secrete it (in bile) into the intestine, where it is metabolized to urobilinogen.
Most of this degraded pigment leaves the body in feces, as a brown pigment called stercobilin.
Exposure of the skin to white light converts bilirubin to lumirubin, which has a shorter half-life than bilirubin.
Phototherapy (exposure to light) is of value in treating infants with jaundice due to hemolysis.
The protein (globin) part of hemoglobin is metabolized or broken down to amino acids, which are released to the circulation.

20. Iron metabolism Iron = 4-5g Per person Hb 65 % of total iron
Reticuloendothelial system + liver = %
Myoglobin = 4%
Intracellular oxidating heme compounds = 1%
Transferrin = 0.1 %
Absorption of Iron:
Mianly from Duodenum.
Heme-Fe+2 from Meat (Myoglobin, hemoglobin)
Fe+2 from small intestine (Fe+3 reduced by Vit C & ferrireductase(FR) to Fe+2 for absorption)
Transport of Iron:
Iron + Apotransferrin [protein from liver]  Transferrin (Bound)  is taken up by endocytosis into erythroblasts and cells of the liver, placenta, etc. with the aid of transferrin receptors.
Storage & Recycling:
Ferritin  one of the chief forms in which iron is stored in the body, storage occurs mainly in the intestinal mucosa, liver, bone marrow, red blood cells, and plasma. (4500 Fe+3 ions i.e. 600mg as readily available store).
Hemosidrin  In marcophages of liver and bone marrow (250mg) slow release.
97 % recycled by phagocytes of liver, spleen and bone marrow
Ferritin
Iron Metabolism and Erythropoiesis
Roughly 2/3 of the body’s iron pool (ca. 2 g in women and 5 g in men) is bound to hemoglobin (Hb). About 1/4 exists as stored iron (ferritin, hemosiderin), the rest as functional iron (myoglobin, iron-containing enzymes).
Iron losses from the body amount to about 1 mg/day in men and up to 2 mg/day in women due to menstruation, birth, and pregnancy.
Iron absorption occurs mainly in the duodenum and varies according to need. The absorption of iron supplied by the diet usually amounts to about 3 to 15% in healthy individuals, but can increase to over 25% in individuals with iron deficiency. A minimum daily iron intake of at least 10–20 mg/day is therefore recommended (women > children > men).
Iron absorption
Heme-Fe++:
Fe(II) supplied by the diet (hemoglobin,myoglobin found chiefly in meat and fish) is absorbed relatively efficiently as a heme-Fe(II) upon protein cleavage. With the aid of hemeoxygenase, Fe in mucosal cells cleaves from heme and oxidizes to Fe(III). The tri-ferric form either remains in the mucosa as a ferritin-Fe(III) complex and returns to the lumen during cell turnover or enters the bloodstream.
Non-heme-Fe can only be absorbed as Fe2+. Therefore, non-heme Fe+++ must first be reduced to Fe2+ by ferrireductase(FR;) and ascorbate on the surface of the luminal mucosa . Fe2+ is probably absorbed through secondary active transport via an Fe2+-H+ symport carrier (DCT1) (competition with Mn2+, Co2+, Cd2+, etc.).
A low chymous pH is important since it
(a) increases the H+ gradient that drives Fe2+ via DCT1 into the cell and
(b) frees dietary iron from complexes.
The absorption of iron into the bloodstream is regulated by the intestinal mucosa. When an iron deficiency exists, aconitase (an iron-regulating protein) in the cytosol binds with ferritin- mRNA, thereby inhibiting mucosal ferritin translation. As a result, larger quantities of absorbed Fe(II) can enter the bloodstream.Fe(II) in the blood is oxidized to Fe(III) by ceruloplasmin (and copper). It then binds to apotransferrin, a protein responsible for iron transport in plasma .
Transferrin (= apotransferrin loaded with 2 Fe+3), is taken up by endocytosis into erythroblasts and cells of the liver, placenta, etc. with the aid of transferrin receptors. Once iron has been released to the target cells, apotransferrin again becomes available for uptake of iron from the intestine and macrophages.
Iron storage and recycling Ferritin,(Ferritin is a globular protein complex consisting of 24 protein subunits and is the main intracellular iron storage protein in both prokaryotes and eukaryotes, keeping it in a soluble and non-toxic form. Ferritin which is not combined with iron is called apoferritin). one of the chief forms in which iron is stored in the body, occurs mainly in the intestinal mucosa, liver, bone marrow, red blood cells, and plasma. It contains binding pockets for up to 4500 Fe3+ ions and provides rapidly available stores of iron (ca. 600 mg), whereas iron mobilization from hemosiderin is much slower (250mg Fe in macrophages of the liver and bone marrow). Hb-Fe and heme-Fe released from malformed erythroblasts (so-called inefficient erythropoiesis) and hemolyzed red blood cells bind to haptoglobin and hemopexin, respectively. They are then engulfed by macrophages in the bone marrow or in the liver and spleen, respectively, resulting in 97% iron recycling . An iron deficiency inhibits Hb synthesis, leading to hypochromic microcytic anemia: MCH "26 pg, MCV "70 fL, Hb "110 g/L. The
primary causes are: ! blood loss (most common cause); 0.5mg Fe are lost with each mL of blood;
! insufficient iron intake or absorption;
! increased iron requirement due to growth, pregnancy, breast-feeding, etc.;
! decreased iron recycling (due to chronic infection);
! apotransferrin defect (rare cause).
Iron overload most commonly damages the liver, pancreas and myocardium (hemochromatosis). If the iron supply bypasses the intestinal tract (iron injection),the transferrin capacity can be exceeded and the resulting quantities of free iron can induce iron poisoning.
B12 vitamin (cobalamins) and folic acid are also required for erythropoiesis (!B). Deficiencies
lead to hyperchromic anemia (decreased RCC, increased MCH). The main causes are lack of
intrinsic factor (required for cobalamin resorption) and decreased folic acid absorption due to malabsorption (see also p. 260) or an extremely unbalanced diet. Because of the large stores available, decreased cobalamin absorption does not lead to symptoms of deficiencyuntil many years later, whereas folic acid deficiency leads to symptoms within a few months.

21. FR=ferrireductase
Daily Iron Loss
Male: 1mg/day
Females: 2mg/day
Daily Iron Requirement
Male: 1mg/day
Females: 2mg/day

22. Blood Transfusion
Whole blood transfusions are routine when blood loss is rapid and substantial.
In all other cases, infusions of packed red cells (whole blood from which most of the plasma has been removed) are preferred for restoring oxygen-carrying capacity.
The usual blood bank procedure involves collecting blood from a donor and then mixing it with an anticoagulant, such as certain citrate or oxalate salts, which prevents clotting by binding with calcium ions.
The shelf life of the collected blood at 4°C is about 35 days.
Because blood is such a valuable commodity, it is most often separated into its component parts so that each component can be used when and where it is needed.

23. ABO Blood Group BLOOD TYPES
The membranes of human red cells contain a variety of blood group antigens, which are also called agglutinogens.
Antibodies against red cell antigens are called agglutinins.
When the plasma of a type A individual (containing Anti-B antibodies) is mixed with type B red cells, the anti-B antibodies cause the type B red cells to clump (agglutinate).
The most important and best known of these are the A and B antigens, but there are many more. eg
MNSs, Lutheran, Kell, Kidd,

25. ABO Blood Group
The individuals are divided into four major blood types on this basis of presence of these antigens.
Type A individuals have the A antigen,
Type B have the B,
Type AB have both, and
Type O have neither.
These antigens are found in many tissues in addition to blood:
E.g.. salivary glands, saliva, pancreas, kidney, liver, lungs, testes, semen, and amniotic fluid.
Chemsitry of Anitgens:
The A and B antigens are complex oligosaccharides that differ in their terminal sugar.
On red cells they are mostly glycosphingolipids,
whereas in other tissues they are glycoproteins.
An H gene codes for a fucose transferase that puts a fucose1 (hexose dexoy sugar) on the end of these glycolipids or glycoproteins, forming the H antigen
H-antigen is usually present in individuals of all blood types.
Fucose is a hexose deoxy sugar with the chemical formula C6H12O5. It is found on N-linked glycans on the mammalian, insect and plant cell surface
Ceramides are a family of lipid molecules.

26. ABO Blood Group
Individuals who are type A have a gene which codes for a transferase that catalyzes placement of a terminal N-acetylgalactosamine on the H antigen,
Individuals who are type B have a gene which codes for a transferase that places a terminal galactose.
Individuals who are type AB have both transferases.
Individuals who are type O have neither, so the H antigen persists.
It now appears that type O individuals have a single-base deletion in their corresponding gene. This creates an open reading frame, and consequently they produce a protein that has no transferase activity.

27. ABO Blood Group Subgroups of blood types A and B Antibody Development:
Most important being A1 and A2.
A1 cell has about 1,000,000 copies of the A antigen on its surface,
A2 cell has about 250,000 copies of the A antigen on its surface
Antibody Development:
Antigens very similar to A and B are common in intestinal bacteria and possibly in foods to which newborn individuals are exposed.
Therefore, infants rapidly develop antibodies against the antigens not present in their own cells.
Thus,
type A individuals develop anti-B antibodies,
type B individuals develop anti-A antibodies,
type O individuals develop both,
and type AB individuals develop neither.
Blood Typing Test:
Blood typing is performed by mixing an individual's red blood cells with antisera containing the various agglutinins on a slide and seeing whether agglutination occurs.

28. Bombay phenotype
Missing H-gene so no fucose tranferase so no fucose and no H-antigen that
Forms the base for A and B Antigen.
No fucose

29. Bombay Phenotype
This blood phenotype was first discovered in Bombay, now known as Mumbai, in, by Dr. Y.M. Bhende.
hh is a rare blood group also called Bombay Blood group. Individuals with the rare Bombay phenotype (hh) do not express H antigen (the antigen which is present in blood group O).
So whatever alleles they may have of the A and B blood-group genes, they cannot make A-anitgen or B-antigen on their red blood cells,because A antigen and B antigen are made from H antigen.
As a result, people who have Bombay phenotype can donate to any member of the ABO blood group system (unless some other gene, such as Rhesus, is checked for compatibility), but they cannot receive any member of the ABO blood group system's blood (which always contains one or more of A and B and H antigens), but only from other people who have Bombay phenotype.
The usual tests for ABO blood group system would show them as group O, unless the hospital worker involved has the means and the thought to test for Bombay group.

30. Rh Blood Groups
45 different types of Rh agglutinogens, each called an Rh factor.
Three, the C, D, and E antigens, are fairly common.
Rh antigen  first identified in rhesus monkeys.
As a rule, ABO and Rh blood groups reported together eg, O+, A–, and so on.
If an Rh– person receives Rh+ blood, the immune system becomes sensitized and begins producing anti-Rh antibodies against the foreign antigen soon after the transfusion.
Hemolysis does not occur after the first such transfusion because it takes time for the body to react and start making antibodies.
But the second time, and every time thereafter, a typical transfusion reaction occurs in which the recipient’s antibodies attack and rupture the donor RBCs. eg Erythorblastosis fetalis1
Prevention:
Anit-Rh antibodies given after every Rh+ birth. [RhoGAM]
1- An important problem related to the Rh factor occurs in pregnant Rh– women who are carrying Rh+ babies. The first such pregnancy usually results in the delivery of a healthy baby. But, when bleeding occurs as the placenta detaches from the uterus, the mother may be sensitized by her baby’s Rh+ antigens that pass into her bloodstream. If so, she will form anti-Rh antibodies unless treated with RhoGAM before or shortly after she has given birth. (The same precautions are taken in women who have miscarried or aborted the fetus.) RhoGAM is a serum containing anti-Rh agglutinins. Because it agglutinates the Rh factor, it blocks the mother’s immune response and prevents her sensitization. If the mother is not treated and becomes pregnant again with an Rh+ baby, her antibodies will cross through the placenta and destroy the baby’s RBCs, producing a condition known as hemolytic disease of the newborn, or erythroblastosis fetalis. The baby becomes anemic and hypoxic. In severe cases, brain damage and even death may result unless transfusions are done before birth to provide the fetus with more erythrocytes for oxygen transport. Additionally, one or two exchange transfusions (see Related Clinical Terms) are done after birth. The baby’s Rh+ blood is removed, and Rh– blood is infused. Within six weeks, the transfused Rh– erythrocytes have been broken down and replaced with the baby’s own Rh+ cells.

31. Rh Factor

32. Blood Transfusion Reactions
When mismatched blood is infused, a transfusion reaction occurs
Donor’s red blood cells  attacked by the recipient’s plasma agglutinins.
Donor’s plasma antibodies may also agglutinate the host’s RBCs, but they are so diluted that this does not usually present a serious problem.
Initially, agglutination clogs small blood vessels throughout the body.
During the next few hours, the clumped red blood cells begin to rupture or are destroyed by phagocytes, and their hemoglobin is released into the bloodstream.
These events lead to two easily recognized problems:
The oxygen-carrying capability of the transfused blood cells is disrupted
The clumping of red blood cells in small vessels hinders blood flow to tissues beyond those points.
Less apparent, but more devastating, is the consequence of hemoglobin escaping into the bloodstream.
Circulating hemoglobin passes freely into the kidney tubules, causing cell death and renal shutdown. If shutdown is complete (acute renal failure), the person may die.

33. Blood Transfusion Reactions
Transfusion reactions can also cause
fever,
chills,
low blood pressure,
rapid heartbeat,
nausea,
vomiting, and general toxicity;
but in the absence of renal shutdown, these reactions are rarely lethal.
Treatment of transfusion reactions is directed toward preventing kidney damage by administering fluid and diuretics to increase urine output, diluting and washing out the hemoglobin.
Some laboratories are developing methods to enzymatically convert other blood types to type O by clipping off the extra (A- or B-specific) sugar residue.
Autologous (auto = self) transfusions.
The patient predonates his or her own blood, and it is stored and immediately available if needed during or after the operation. .
Iron supplements are given, and as long as the patient’s preoperative hematocrit is at least 30%, one unit (400–500 ml) of blood can be collected every 4 days, with the last unit taken 72 hours prior to surgery.