BLOOD Composition and function of

.      Introduction        A.  The internal environment is regulated by the fluids which bathe the cells:             1. Interstitial fluid (IF) is found outside cells and in between the cells               2. Lymph inside lymph vessels               3. Blood within blood vessels         B. Hematology is the science which studies blood and blood disorders

Blood Fluid connective tissue Functions include

Transporting dissolved gases, nutrients, hormones, and metabolic wastes

Regulating pH and ion composition of interstitial fluids

Restricting fluid loss at injury sites Defending the body against toxins and

pathogens Regulating body temperature by absorbing

and redistributing heat

Figure 19.1a

The Composition of Whole Blood

Composition of Blood

Total Blood Volume : 5-6 liters (8% of body weight or 80ml/kg body weight)

Specific Gravity : 1050-1060 Viscosity : 4-5 times that of

water Ph : 7.4 (.05); it is alkaline in

nature In acidosis Ph of blood falls

below 7.38 and in alkalosis Ph is more than 7.42

Figure 10.1

Composition of Blood

Blood contains plasma & formed elements(cells)

Cells represent 45% of blood volume Hematocrit represents the percentage

of red blood cells in blood (called Packed Cell Volume (PCV)

            1. A lower than normal hematocrit is representative of a condition known as anemia

             2. An abnormally high hematocrit is representative of polycythemia

Hematocrit “ for males: 40%-54% (47%); Females: 38%-46% (42%)

Blood Components:

Figure 16-1: Composition of blood

Blood Components: Cells

Erythrocytes Red Blood Cells (RBC) O2 & CO2 transport

White Blood Cells (WBC) Immune defense Phagocytosis

Platelets: clotting

Blood Cells

Plasma is a clear ,straw colored fluid portion of blood & represents 55% of the total blood volume.

It contains 91% water and 9% solids( 1% inorganic molecules ,8% organic molecules)

The major inorganic molecules are Na+ ,Ca++, Hco3

-, K+ , Mg++, Cu++, Po4

-3

Of 8% organic molecules

7% are Plasma Proteins

(6.4-8.3 gm%)

1% are Non Protein Nitrogenous substances(urea,Uric acid,Creatinine,Xanthin)

. plasma composition            1. 92% water            2.   9% solutes                  a. Proteins -albumins; globulins (alpha, beta, gamma); fibrinogen                  b. Nutrients                  c. Enzymes                  d. Hormones                  e. Respiratory gases (oxygen, carbon dioxide)                  f. Electrolytes (sodium, chloride, potassium)                  g. Waste products (urea, uric acid, creatinine, H+, etc)

Figure 10.1

Plasma

Water Plasma proteins

Albumin (60%) Osmotic Gradient

Globulins (Ab) Fibrinogen

Other solutes Electrolytes Nutrients Trace Elements Dissolved gases

Serum = Plasma – Clotting factors

Serum = Plasma – Clotting factors

• Plasma Proteins• Albumin• Globulin- α₁, α₂, β₁, β₂, γ• Fibrinogen

Origin: Liver- Albumin & FibrinogenPlasma cells, lymphocytes, tissue

macrophages- Globulin

Plasma proteins

concentration 65 –80 g l (6.4-8.3gm%) simple or conjugated (glycoproteins,

lipoproteins) separation:

a) salting-out methods albumin, globulins, fibrinogen

b) electrophoresis albumin, globulin 1, 2, , fractions:

-

+

2

1

albumin

Plasma proteins

more than 90% are synthesized in the liver

Albumins 55% of plasma proteins Responsible for viscosity and osmotic

pressure of blood 3-5 gm% (average 4.8gm%)

Plasma Proteins

Globulin is 38%of plasma Proteins 2-3 gm%(average 2.3gm%) 13% α globulin: 0.79-0.84 gm% 14% β globulin : 0.78-0.81 gm% 11% γ globulin: 0.66-0.70 gm% A/G ratio :1.7-1

7% Fibrinogen: 0.3 gm% Prothrombin: 40 mg %

Globulins ~38% of plasma proteins Include immunoglobins which attack foreign

proteins and pathogens Include transport globulins which bind ions,

hormones and other compounds Fibrinogen

Converted to fibrin during clotting Removal of fibrinogen leaves serum

Functions of Plasma Proteins

Exert Osmotic Pressure : Contribution to Blood Viscosity Role in Coagulation of Blood Role in Defense Mechanism of Body Role in maintaining acid –base balance

of body Transport Function

Exert osmotic pressure Plasma proteins can’t cross capillary

membrane so exert colloidal osmotic pressure of about 25mmHg on capillary membrane. 80% of COP is contributed by Albumin

COP plays an important role in exchange of water between blood & tissue fluid

At arterial end of capillaries, due to high Hydrostatic Pressure than COP there occurs filtration of fluid out in tissues

At venous end of capillaries due to lower HP than COP there occur absorption of fluid from tissues in to vessels

Contribution to Blood Viscosity Shape of Plasma Proteins Greatly

contribute to Viscosity of Blood. Fibrinogen & globulins are main

contributors due to their asymetrical shape

The Blood Viscosity plays an important role in the maintenance of Blood Pressure by providing resistance to flow of blood .

Role in Coagulation of Blood The Fibrinogen ,Prothrombin & other

coagulation proteins present in plasma play important role in the coagulation of Blood.

Whenever ,there is injury to blood vessels, the fibrinogen is converted in to fibrin which form blood clot

Role in Defense

The Gamma globulins are anti bodies which plays an important role in the immune system meant for defense of the body against the micro-organisms

Acid-Base Balance Plasma Proteins acts as Buffers Contribute for 15% buffering capacity

of Blood PP are amphhoteric in nature means

can combine with acids and bases. In Acidic Ph the NH2 group of the

proteins acts as base & accept proton & is converted to NH4

In Alkaline Ph the COOH group of the protein act as acid & can donate a proton & thus become COO-

Transport Function

PP can combine easily with many substances & play an essential role in their transport

CO2 is transported by PP in the form of carb-amino compounds

Thyroxine- is transported by an alpha –globuline called TBP

Cortisol is transported by transcortin(mucoprotein)

Transport Function Vitamins A,D & E are transported by the

high and low density lipoproteins. Bilirubin is transported with Albumin &

also with fractions of alpha globulin. Drugs are transported with Albumin Ca++ of plasma is 50% bound to proteins

for transport. Cu is bound to ceruloplasmin(alpha

globulin) for transport Free HB in the vessels is bound to

haptoglobin & is carried to reticulo-endothelial system

Causes of Albumin Deficiency

Liver diseases (cirrhosis) – decrease in the ratio of albumin to globulins

Protein malnutrition

Excessive excretion by kidneys (renal disease)

Mutation causing analbuminemia (affects splicing)