Introduction to the blood module and its components

Introduction to the blood module and its components

• • • Functions of blood Production of RBC, WBC, Platelets Characteristics of blood cells Hemostasis Blood transfusion reactions Immunity

Blood – Physical Characteristics • Volume – Adult ♂ – Adult ♀ • Viscosity • p. H • Color 5 -6 L 4 -5 L 5 times the viscosity of water 7. 35 – 7. 45 (slightly alkaline) – (oxygenated blood) – (deoxygenated blood) scarlet red deep red

Whole Blood Plasma Formed Elements (46 -63%) (37 -54%) 1. Water (92%) 1. Red Blood Cells (99. 9%) 2. Plasma Proteins (7%) 2. Platelets 3. Other Solutes (1%) 3. White Blood Cells (0. 1%)

FUNCTIONS OF BLOOD 1. Nutrient function 2. Transportation of gases 3. Excretory function 4. Transportation of hormones and enzymes 5. Regulation of water balance 6. Regulation of acid base balance 7. Regulation of body temp. 8. Storage function

9. Defensive function

Red Blood Cells (Erythrocytes) • Most abundant blood cells • Count – Males 5200, 000 ± 300, 000/cmm – Females 4700, 000 ± 300, 000/cmm • Contain red pigment hemoglobin carrier of O 2 and CO 2 • Each RBC is a biconcave disc – Diameter – Thickness – Centre 7. 5 -8µm 2 - 2. 5µm 1µm

Erythrocyte diameters

Erythrocytes • Why a biconcave disc? – Great excess of cell membrane for the quantity of material inside – Provides a large surface area for exchange of gasses – Enables them to bend and flex in small blood vessels RBC bending to fit through a small capillary

Erythrocytes • RBCs lack a nucleus and most other organelles. – Simply membranous bags of hemoglobin – Can deform to any shape – Diapedesis- squeeze through small pores

RBCs

Erythrocytes • Life span only 120 days – No nucleus, No DNA & RNA – Cannot synthesize proteins for repair or growth – Irreparable cell membrane becomes fragile ruptures when passing through tight spots in spleen • Viscosity of blood

Erythrocytes • Hemoglobin • Carry – O 2 – CO • Hb the biggest buffer in the blood • Carbonic anhydrase – CO 2+H 2 O→H 2 CO 3↔ H++HCO 3 -

• RBC have the ability to concentrate upto 34 gms in each 100 ml of cells • 1 gm of Hb combines with 1. 34 ml of oxygen • Males 15 gms of Hb/100 ml of cells---20 ml of oxygen carried in 100 ml of cells • Females 14 gms of Hb/100 ml of cells---19 ml of oxygen carried in 100 ml of cells

Hemoglobin • The O 2 binding and transporting protein found in extreme abundance in RBCs • Hb levels are reported in grams of Hb per 100 m. L of whole blood (g/d. L). – 14 -18 g/d. L in adult ♂ – 12 -16 g/d. L in adult ♀ – 14 -20 g/d. L in infants

Hemoglobin • Large protein MW 64000 • 4 polypeptides – 2 chains and 2 β chains • Each chain heme, an iron-containing pigment – The iron in heme is able to reversibly bind an oxygen molecule. – O 2 can bind to Hb in the lungs and then released in the tissues

Hemoglobin

Absolute values • Total count – ♂ 5000, 000 ± 300, 000 – ♀ 4700, 000 ± 300, 000 • Size – Diameter =7. 8 µ – Outer edges = 2. 5 µ – Centre = 1 µ • Hemoglobin contents – 34 % of cell volume – ♂14 -16. 5 g/dl of whole blood – ♀12 -15 g/dl of whole blood

Absolute values • Hematocrit – ♂ 40 -50 % – ♀ 37 -47 % • O 2 carrying capacity – Each molecule carries 4 O 2 – 1 G Hb 1. 34 ml – 100 ml of blood • ♂ 20 ml • ♀ 19 ml • MCV 80 -100 fl • MCH 27 -34 pg • MCHC 31 -35 g/dl

Types of plasma proteins • Albumin 4. 5 – 5 g/dl • Globulin 2. 0 – 3 g/dl – 1 globulin – 2 globulin – globulin • Fibrinogen 0. 2 – 0. 45 g/dl • Total amount = 6 -8 g/dl

Nutrition • Plasma proteins break down to supply Amino acids for different cells of the body • Synthesized constantly by the liver • 10 -12 grams of albumin turn over occurs in 24 hours

Viscosity • Plasma proteins contribute towards the viscosity of the blood. . • Excessive viscosity impedes the blood flow.

Osmotic pressure • 28 mm Hg osmotic pressure • Albumin contribute about 80 % of it – Most abundant – Smallest molecule • Hypoproteinemia results into generalized edema because of low osmotic pressure – Nephrotic syndrome

Carrier function • Albumin transports – Bilirubin – Hormones – Drugs • Thyroxin binding globulin and pre albumin carry thyroid hormone • Transcortin carries cortisol. • Lipoproteins carry lipids. • Ceruloplasmin carry copper • Transferrin carry iron • Haptoglobin binds with free hemoglobin

Blood coagulation • Most of the clotting factors are part of plasma proteins – Fibrinogen – Prothrombin – Labile factor – Stable factor – Christmas factor – Stuart Prower factor – Hageman factor – FSF

Blood coagulation • Anticoagulants – Heparin – Antithrombin

Buffer action • The acceptance of H+ Ions is called buffer action. • 15 % buffering capacity of the blood • At p. H 7. 4 (normal p. H) mostly negatively charged and can combine with cations.

Immunity • Antibodies are gamma globulins • Immunoglobulins – Ig G – Ig M – Ig A – Ig D – Ig E

Precursors of active substances • Some very important protein present in inactive form as part of plasma proteins • Activated for very important specific functions – Angiotensin – Erythropoietin

Enzymes • Many circulating enzymes are also part of plasma proteins – Alkaline phosphatase – Acid phosphatase – AST aspatate amino transferase – ALT alanine amino transferase

MCQ The normal concentration of RBCs in an adult female is a. 2, 700, 000/cubic mm b. 5000/cubic mm c. 5, 200, 000/cubic mm d. 4, 700, 000/cubic mm e. 30, 000 / cubic mm

The diameter of a biconcave disc of RBC is a. 7 -8 µm b. 1 -2 µm c. 3 -4 µm d. 12 -14 µm

Thank-you Questions ? ?