1. THE BLOOD

2. Topics Body fluids Blood constituents & their functions Hemostasis
Intracellular fluid, extracellular fluid. Homeostasis
Blood constituents & their functions
Plasma
Plasma proteins & colloidal osmotic pressure
Electrolytes & crystal osmotic pressure
Water
Cellular elements : Erythrocytes, Leukocytes & Platelets
Hemostasis
Blood groups

3. Body fluids Total body water (by weight) is about 42L.
60% is ICF & remaining 40% is ECF (75% ISF & 25% plasma)

4. Functions of blood Transportation Regulation Protection O2 & CO2
Nutrients
Waste products
Hormones etc.
Regulation pH
Body temperature
Protection
Immunity
Blood coagulation

5. Components of blood Plasma Blood cells (Formed elements)
Erythrocytes or Red blood cells (RBC)
Leucocytes or White blood cells (WBC)
Thrombocytes or Platelets

9. Hematocrit

10. Plasma Composition: Water (92%) Proteins (6~8%)
Inorganic constituents (~1%) – Na+, Cl-, K+,Ca2+, etc.
Nutrients
Waste products (nitrogenous waste like urea)
Dissolved gasses (O2 & CO2)
Hormones

11. Plasma proteins Fibrinogen Albumins (60-80%)
Most important in maintenance of osmotic balance
Produced in liver
Globulins (α1, α2, β1, β2 & γ)
Important in transport of materials through the blood (eg: Iron (transferrin), thyroid hormone (transthyretin) etc)
Clotting factors
Produced by liver, except γ-globulins which are immunoglobulins synthesized by lymphocytes
Fibrinogen
Important in clotting
Produced by liver

12. Plasma osmotic pressure
Crystalloid osmotic pressure
Pressure generated by all crystal substances, particularly electrolytes
Important in maintaining fluid balance across cell membrane
Colloid osmotic pressure
Osmotic pressure generated by plasma proteins, especially albumin
Important in fluid transfer across capillaries

13. Erythrocytes
Morphology
Biconcave discs
Without a nucleus
RBC count
♂: 4.5~5.5million cells per cubic mm of blood or 4.5~5.5 x 1012/L
♀: 3.8~4.6million cells per cubic mm of blood or 3.8~4.6 x 1012/L

14. Functions of hemoglobin
Carries oxygen from lungs to tissue, and carbon dioxide from tissues to lungs.
It is an excellent acid-base buffer
Normal values:
♂- 12~16 g/dL, ♀- 11~15 g/dL

15. Erythrocyte sedimentation rate
The distance that RBCs settle in a tube of blood in one hour.
Normal value:
♂- 0~15mm, ♀- 0~20mm
Rouleaux formation
ESR is an indication of inflammation (especially Chronic disease) which increases in many diseases, such as tuberculosis, rheumatoid arthritis etc.

16. Osmotic fragility
The susceptibility of a red blood cell to break apart when exposed to saline solutions of a lower or higher osmotic pressure than that of the human cellular fluid.
Osmotic fragility is more common in spherocytosis, megaloblastic & microcytic anemia etc.

18. Carbonic anhydrase of RBC
Enzyme that catalyzes the reversible reaction between CO2 and H2O to form H2CO3 (carbonic acid) is CA.
This reaction makes it possible for the water of the blood to transport enormous quantity of CO2 in the form of bicarbonate ion (HCO3-).
In tissue capillaries CO2 combines with water inside the RBC to form carbonic acid that dissociates to form bicarbonate ions & hydrogen ions.
The chloride shift is the movement of chloride ions into RBC as bicarbonate ions move out.

20. Hemopoesis
In embryonic life first RBC’s are produced by yolk sac, which is later on taken up by mainly liver, & also by spleen & lymph nodes.
During last month of gestation & after birth the RBC is synthesized exclusively from bone marrow.

22. Erythropoesis
Proerythroblasts are formed from CFU-E cells after stimulation
First generation cells are basophil erythroblast with little Hb.
In succeeding generations the Hb conc. steadily increases.
The nucleus condenses & get extruded from cell, & ER also reabsorbed at the stage of reticulocytes.
Reticulocytes(baby RBC) move to capillaries by a process called diapedesis. Within 1 or 2 days it is turned into a mature RBC.

23. Factors effecting erythropoiesis
Tissue oxygenation is the most essential regulator of RBC production.
Hypoxia cause erythropoietin formation from interstitial fibroblasts(proximal convoluted tubule) of kidneys (90%) & liver sinusoids.
Erythropoietin stimulate production of proerythroblast from stem cells & also speeds up the rest of process, but new RBCs are found in circulation after 5 days.

24. Nutrient requirement for erythropoiesis
Many vitamins, minerals & proteins are required for RBC production.
Clinically, Folic acid, Vit. B12, and iron are the most important. Deficiencies in these result in characteristic anemia.
Megaloblastic anemia & pernicious anemia

25. Destruction of RBC Average lifespan of RBC is about 120 days
RBC lack nucleus, mitochondria, ER etc., but have enzyme system which regulate
Glucose metabolism for production of ATP
Maintain pliability (flexibility) of plasma membrane
Iron of Hb is kept in ferrous form rather than ferric
Prevent oxidation of proteins in RBC
Red cells self destruct, as the membrane becomes fragile, when they pass through 3μm wide red pulp of spleen.
Kupffer cells & other macrophages phagocyte the Hb & release iron to blood, transported by transferrin to be reused in Hb synthesis. The porphyrin is converted into bilirubin (bile pigment).

32. White Blood Cells
Granulocytes
Agranulocytes
Types of WBC

33. WBC count WBC Neutrophils 50-70 Eosinophils 1-4 Basophils 0-1
% of total white cell
Neutrophils
50-70
Eosinophils
1-4
Basophils
0-1
Lymphocytes
20-40
Monocytes
2-8
Granulocytes or polymorphonuclear leukocytes are of 3 types –
Neutrophils with neutrophilic granules & multilobed nucleus,
Eosinophils with acidic granules & spectacle shaped bilobed nucleus, and
Basophils with coarse basophilic granules & bilobed nucleus. These granules contain active substances involved in inflammatory & allergic reactions.
Agranulocytes are lymphocytes and monocytes.
Lymphocytes have large round nucleus with scanty cytoplasm, and Monocytes have abundant agranular cytoplasm and kidney-shaped nuclei.

34. Neutrophils: Remain in circulation for about hrs & then move into other tissues where they become motile and leak out, & phagocytize bacteria, antigen-antibody complexes etc. They contain lysozymes which can destroy certain bacteria.
Eosinophils: Leave circulation & enter tissues having inflammatory reactions. It produces anti-inflammatory chemicals that destroys chemicals like histamine. They attacks certain worm parasite. Their numbers are elevated in blood of people with allergy & parasitic infection.
Basophils: Play a role in allergic & inflammatory reactions. Release histamine, which cause inflammatory reactions, & heparin, which inhibits blood clotting.

35. Lymphocytes: Smallest WBC
Lymphocytes: Smallest WBC. Although lymphocytes originate in bone marrow, they migrate to lymphatic tissues (lymph nodes & nodules, spleen, tonsils, thymus) where they can proliferate & produce more lymphocytes.
B lymphocyte cells mainly produce antibodies, memory cells, plasma cells & other chemicals responsible for destroying microorganism.
T lymphocyte cells mainly produce helperTcells(CD4), cytotoxicTcells(CD8), suppresorTcells, memoryTcells etc. It acts against viruses, & are responsible for graft rejection, tumor control etc. Lymphocytes also contributes to allergic reactions & regulation of immune system.
Monocytes: Largest WBC. Leave circulation & get transformed into macrophages & phagocytize bacteria, cell debris etc. Increase in monocyte is associated with chronic infections. It also act as antigen presenting cell, which can activate lymphocytes.

36. Platelets
Formed in bone marrow from cells called megakaryocytes. Doesn’t have nucleus, but can secrete variety of substances.
2-4μm in diameter, Life-span: days (~10)days.
Play an important role in hemostasis.
Normal count: 1,50,000 – 4,50,000 /cu mm of blood

40. Hemostasis
The arrest of bleeding following injury and it is the result of three interacting, overlapping mechanisms.
Vascular spasm
Formation of platelet plug
Blood coagulation (clotting)

41. Vascular spasm
Local myogenic spasm (initiated by direct damage to vascular wall)
Local autacoid (physiologically active internal secretion) factors from the traumatized tissues (endothelin & tissue factor) & platelets (serotonin & thromboxane A2 – prostaglandin derivatives)
Nervous reflexes (initiated by pain receptors)
Aspirin (anti-inflammatory, antipyretic; pain killer drugs) act by inhibiting prostaglandin synthesis. It inhibits production of thromboxane & hence reduce platelet activation.

42. Platelet contents
Actin, myosin, & another contractile protein thrombosthenin, causing platelet contraction.
Residuals of ER & Golgi apparatus synthesize various enzymes & stores calcium.
Mitochondria produce ATP & ADP.
Enzyme system synthesizes various prostaglandin.
Contain fibrin stabilizing factor (factor XIII), which helps in final step of coagulation.
Platelet derived growth factor – cause endothelial cells, vascular smooth muscles, & fibroblasts to multiply & grow.

43. Mechanism of platelet plug formation
Platelets when come in contact with damaged vascular surface, especially collagen, they get activated.
Begin to swell, form irradiating pseudopods, contractile proteins cause the release of granule contents (ADP & thromboxane A2), which makes the platelets sticky, & they stick on to collagen and to another protein called von Willebrand factor ( vWF ), a plasma protein which leaks into traumatized tissue.
Activated platelets attracts other platelets & activate them, & they stick to each other, forming the platelet plug.
The platelet plugging mechanism is important in closure of minute ruptures in small blood vessels. Its deficiency (thrombocytopenia) may result in purpura.

44. Blood coagulation Clotting factors Synonyms I Fibrinogen
II Prothrombin
III Thromboplastin, Tissue factor
IV Calcium
V Proaccelerin, labile factor
VII Proconvertin, stable factor
VIII Antihemophilic factor A (AHF-A)
IX Christmas factor, AHF-B
X Stuart-Prower factor
XI Plasma thromboplastin antecedent, AHF-C
XII Hageman factor, glass factor, contact factor
XIII Fibrin stabilizing factor, Laki-Lorand factor

45. 3 steps & 2 pathways

47. Fibrin stabilization

48. Scanning electron micrograph of clot

49. Final clot with entangled blood cells

50. Blood groups
Erythrocytes on their surfaces carry many antigens, but the most important & commonly recognized are the A & B substances and Rhesus (Rh) factor

51. Rh group Inherited independent of ABO system
Rh +ve : Antigen present (mainly D antigen) & no antibody
Rh –ve : No antigen & antibodies will be produced if exposure occurs