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 ♂ 5-6L Adult ♀ 4-5L Viscosity 5 times the viscosity of water pH 7.35 – 7.45 (slightly alkaline) Color (oxygenated blood) scarlet red (deoxygenated blood) deep red

Whole Blood Plasma Formed Elements (46-63%) (37-54%) Water (92%) Plasma Proteins (7%) Other Solutes (1%) Red Blood Cells (99.9%) Platelets White Blood Cells (0.1%)

FUNCTIONS OF BLOOD 1. Nutrient function 2. Transportation of gases 3 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 O2 and CO2 Each RBC is a biconcave disc Diameter 7.5-8µm Thickness 2- 2.5µm Centre 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 Viscosity of blood 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 Hb the biggest buffer in the blood CO2 CO Hb the biggest buffer in the blood Carbonic anhydrase CO2+H2O→H2CO3↔ H++HCO3-

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 O2 binding and transporting protein found in extreme abundance in RBCs Hb levels are reported in grams of Hb per 100mL of whole blood (g/dL). 14-18g/dL in adult ♂ 12-16g/dL in adult ♀ 14-20g/dL in infants

Hemoglobin Large protein MW 64000 4 polypeptides 2  chains and 2 β chains Each chain heme, an iron-containing pigment The iron ion in heme is able to reversibly bind an oxygen molecule. O2 can bind to Hb in the lungs and then released in the tissues

Hemoglobin

Hemoglobin 92-95% Hb A (22) (MW 64,458)  3-5% HbA1c (glycosylated 22)  2-3% Hb A2 (22)  1-2% Hb F (fetal 22)

Absolute values Total count Size Hemoglobin contents ♂ 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 O2 carrying capacity MCV 80-100 fl ♂ 40-50 % ♀ 37-47 % O2 carrying capacity Each molecule carries 4 O2 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 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 pH 7.4 (normal pH) 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

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