Blood and Functions of Blood

Blood and Functions of Blood Blood is a fluid connective tissue. Blood cells are known as Corpuscles. Blood always exists from the pre occurring blood cells Blood lacks fibers. It is heavier than water PH in between 7.3 to 7.4 It is more viscous than water The matrix of the blood is plasma Blood constitutes 2 main components plasma and corpuscles. Composition of Blood lood

Bloodelements corpuscles Formed of blood

Plasma

Erythrocytes (RBCs)

Leucocytes (WBC’s)

Granulocytes

Eosinophils

Basophils

Thrombocytes (Blood platelets)

Agranulocytes

Neutrophils

Monocytes

Lymphocytes

Plasma Plasma is a viscous aqueous solution which is slightly alkaline. It contains many organic and inorganic substances and it has about 92 % of water and 8% of solid salts (or) solutes The solute includes glucose, Aminoacid, Fatty acids, Vitamins, Enzymes, Harmones, Antibodies, oxygen, urea, uric acid & creatinine etc. Out of the 8% solid content, 7% is the organic component and 1% inorganic content. Plasma contains 3 major classes of plasma proteins with in its 7% content :(i) Albumin (4.4 %) (ii) Globulin (2.3 %) (iii) Fibrinogen (0.3 %) Albumin is also known as serum albumin. Globulin is responsible for formation of Antibodies. Fibrinogen whose content is very low helps in blood clotting. Blood plasma retains water due to presence of Albumin and Globulin by their osmotic effects. Whenever excessive amount of plasma protein is filtered out of the blood it leads to swelling (or) oedema Albumin and globulin transports various substances such as thyroxin, ferric ions, Fe3+ etc. Globulins have a category called Immunoglobulins which basically act as antibody. These antibodies inactivate micro-organisms and other toxins. Plasma maintains the blood pH by neutralizing strong acid and bases which is dissolve as inorganic constituents Hence plasma acts as acid base buffers

Functions of Plasma 1. Plasma helps in transportation of various chemicals, Harmones , ions etc. 2. Plasma provides body immunities through immunoglobulins. 3. It helps in retention of fluid in the blood

4. It helps in maintenance of blood pH 5. It helps in uniform distribution of heat all over the body. 6. It conducts heat to skin for dissipation. Blood Corpuscles Blood cells are known as corpuscles It forms 40% - 45% of the whole blood Blood corpuscles are of 3 types (i) RBC (ii) WBC RBC (Red blood corpuscles) or [Erythrocytes] RBC are present in all the vertebrates .They are nucleated except in mammals. The shape and size of erythrocytes vary in different class of animals. In humans these are circular, biconcave and non nucleated. Human RBC measures 7 – 8 m. Whenever human erythrocytes mature, it is devoid of all the organelles including nucleus, mitochondria, etc. It is only constituent of a cytoplasm and plasma lemma surrounding is. The entire volume of cell is filled with oxygen adhering pigment called Haemoglobin. Haemoglobin is scattered through out the cell and appears to be red hence the cell is known as RBC. [Hemoglobin is a conjugate protein. The main protein is called globin and the complex protein with the ferrous (Fe+) complex is called heam. The haemoglobin pigment capacity to bind 4 molecules of oxygen to its 4 Ferrous ions Hence it forms oxyhemoglobin.

When oxygen pressure is low oxygen dissociates from the Haemoglobin and CO2 replaces it which is called deoxyhaemoglobin. Hence, Hemoglobin carries oxygen and CO2. Carbondioxide is mainly carried by plasma and the RBC Haemoglobin is a respiratory pigment which is attached by coordination bonding to the O2. WBC (White Blood corpuscles-Leukocytes) (leuko -white) These are non-haemoglobin containing cells comparatively larger than the RBC and appear to be colourless. They can perform ameboid movements Their main function is to defend the body..

If the number of WBCs increase abnormally it leads to Leukemia [Blood cancer] But if the number declines it leads to leucopenia WBCs are of two types (a) Granulocytes [ with cytoplasmic granules] (b) Agranulocytes [ without granules in the cytoplasm (or) with a very low % of granules] (a) Granulocytes : Granules are 68% Granulocytes are further categorized into 3 types (i) Acidophils (Eosinophils) (ii) Basophilis (iii) Neutrophils (i) Acidophils (or) Eosinophils They have bilobed nucleus. They can be stained by acidic dyes. They show hypersensitivity of the body. (ii) Basophils These are minimum in the WBCs. Nucleus is less distinct. They represent most cells. They secretes Histamine, Heparin, and serotonin,

(iii) Neutrophils These does not retain any of the dyes (neither acidic nor basic) They are more in no in WBC. There nucleus is multilobed Neutrophils are phagocytic (feeder) in nature Its number always increases during pus formation (or) bacterial infection. (b) Agranulocytes Granules are 32% if present Granules are either absent or in very low percentage Agranulocytes are produced in the lymph glands like spleen, thymus etc. Agranulocytes are divided into 2 parts Lymphocytes, Monocytes

LYMPHOCYTES

MONOCYTES

These are the smallest WBCs. Nucleus is central Life span is of 3 days Life span is of 3 days It produces chemical called Antibodies

These are the largest WBCs. Nucleus is horse shoe shaped. Life span is of 28 days Life span is of 28 days They are phagocytic (engulfing) in nature

PLASMA Plasma is a viscous solution containing organic and inorganic substances Plasma can coagulate due to presence of Fibrinogen.

SERUM Serum is the blood plasma without fibrinogen protein Serum can not coagulate due t the absence of fibrinogen

Plasma contains normal no. of RBCs and platelets.

It has less no of RBCs and platelets

BLOOD Blood consists of plasma, leukocyte, erythrocytes and platelets. Blood appears to be red due to hemoglobin Glucose concentration is less is blood Blood carries several materials in the body The amount of CO2 and other metabolic waste are normal in the blood. The percentage of ions (Ca2+ and Phosphorous) can be more in the blood with the dissolve metabolized.

Thrombocytes (or) Platelets

LYMPH It consists of plasma and leukocyte. Lymph appears to be transparent due to leukocytes. Glucose concentration is higher in lymph Lymph transfers material from the blood to the body cell. The metabolic wastes are much more in the lymph. The percentage of ions (Ca2+ phosphorous and other protein) can be normal in the lymph

Platelets are also called thrombocytes They are non nucleated, rounded, oval, biconvex, disc likes cells whose number is 3 lacks/mm3 of blood. They bud (form) out from cytoplasm of megakaryocyte of the bone marrow. They are responsible for coagulation of the blood and they have life span of 5 to 6 days when blood vessel injured they clump at the injured part and release certain factors also known as coagulating factors They promote coagulation and hence helps in preventing the blood loss.

FUNCTIONS OF BLOOD 1. Blood transports many substances from one part of the body to the other part. Blood helps in transport of various chemicals, hormones, ions, food materials (from intestine to the various body parts), and respiratory gases (i.e., O2 from lungs to various tissues and CO2 from various tissue to lung.) 2. Blood helps in uniform distribution of heat all over the body. 3. The fluid of blood (plasma) helps in retention of water in the blood. 4. Blood helps in transport of excretory substance (urea ) from tissues to the excretory organs. 5. Blood maintains the body temperature by distribution of heat. 6. Blood helps in maintaining water balance in the body by exchange of water between circulating flood and tissue fluid. 7. Blood helps in maintenance of pH of the body because it has lot of inorganic substance or ions dissolve in plasma which neutralize acid (or) base. 8. Blood (RBCs of blood) capture the oxygen and carbondioxide by haemoglobin and hence, helps in respiration. 9. White blood corpuscles are defensive in function. It provide immunity to the body and secrete various antibodies to kill foreign microorganism. 10. Blood contains various anticoagulant substances like heparin, antithrombin etc. These chemicals does not allow to coagulate the blood. That is, It prevents internal bleeding. 11. The platelets of blood prevent excessive loss of blood by clotting it during injuries.