Human Blood and Blood Groups
- Blood is a fluid connective tissue.
- The quantity of blood in the human body is 7% of the total weight.
- The PH value of blood is 7.4.
- There is an average of 5-6 litres of blood in the human body.
- It fights infection and regulates body temperature.
- Females contain half litre of blood less in comparison to male.
- Blood cells are produced in bone marrow.
- The main functions of the blood are to transport oxygen, carbon dioxide, water and nutrients, hormones around the blood.
- Blood has three major components
- Plasma 55%
- Corpuscles 45%
- Blood platelets (thrombocytes)
- liquid portion of blood.
- It constitutes for about 55% of our blood, 92% of it is water.
- It main functions are
- Maintaining blood pressure.
- Volume to supply critical proteins for blood clotting and immunity.
- Medium for exchange of vital minerals such as sodium and potassium.
- Helps to maintain a proper PH(acid-base) balance in the body.
Red blood corpuscles
- RBCs are disc shaped cells containing hemoglobin, which gives red colour to the blood.
- Amount of haemoglobin is 14/15.6gm/100 cc of blood (11-14 in women).
- RBCs are produced in the spleen and liver in foetus and in the bone marrow.
- Haemoglobin enables the cells to pick up and deliver oxygen to all parts of the body, then pickup carbon dioxide and remove it from tissues.
- Life of RBC is 20dys-120days after which they are broken down in the spleen or liver.
- Product of breakdown of haemoglobin is a pigment (yellow colour), called bilirubin.
- They have no nucleus.
- Disorders Of Red Blood Cells
- Presence of more RBC causes polycythemia.
- Less RBC in blood causes Anemia.
- Nutritional Anemia : lack of iron in food.
- Aplastic, hemolytic, microcytic anemia : sudden change in shape.
- Pernicious Anemia : lack of folic acid, pyridoxine.
- Microcytic anemia : improper supply of oxygen.
- Sickle cell anemia : who are with malaria suffering.
- Blood of most molluscs (marine animals like squids, oysters, snails, octopuses etc) is blue due to the presence of copper protein in hemocyanin.
White Blood Corpuscles
- Also called leukocytes, rounded with a nucleus, far less numerous than RBCs (1:600).
- Life span is 3-4 days.
- It defends the body from infections (scavengers of the body) and provides immunity.
- WBC have nuclei and are also made in bone marrow.
- WBC are two types
- Granulocytes : basophils, eosinophils and neutrophils.
- Agranulocytes : monocytes and lymphocytes.
- Basophils : take up basic stains. Secretes an anticoagulant heparin, which prevents clots within the blood vessels.
- Eosinophils : take up acidic stains. Assists in defence mechanisms.
- Neutrophils : stains equally with both acidic and basic types. Most numerous of the WBC. Defence.
- Monocytes : largest of all, Very motile, Defence.
- Lymphocytes : 25% of WBC. Takes part in antigen and antibody formation.
- responsible for clotting.
- Also called thrombocytes. Formed in bone marrow, about 250,000 lakhs/cumm of blood life 8-10 days.
- Lymph : plasma+WBC
- Lymph forms a second circulatory system. It acts as a middle man between blood and tissue.
- Spleen produces lymph. At the same time it also acts as the graveyard of lymph.
- Father of blood grouping : karlandsteiner. He discovered A,B and O blood groups in 1900.
- Blood circulation was discovered by William Harvey.
- Decastello and Sturli in 1902 discovered AB blood group.
- Antigens: they are proteins and are found on the surface of RBCs. Antigens are A and B.
- Antibodies : they are produced in lymph glands and present in blood plasma. Antibodies are A and B.
- AB is a universal recipient.
- O is a universal donor.
- RH factor : it is based on RH antigen. A person can be Rh+ or Rh-.
- Rh+ can receive blood from Rh- but no vice-versa.
- Blood transfusion technique was first developed by James Blundell in 1825.
- Wrong stability of blood leads to death (clumping).
- Citrate phosphate dextrose is used to preserve blood in blood banks.
|Blood group||Antigen||Antibody||Can donate to||Can receive from|
|A||A||B||A, AB||A, O|
|B||B||A||B, AB||B, O|
|AB||A & B||AB||AB, A, B, O|
|O||A & B||A, B, AB, O||O|