Category: Biology Second Paper Lecture Sheet

Every cubic milliliter of blood contains 50-54 lakh red blood cells in the male body, 45-48 lakh in the female body, 60-70 lakh in the child’s body and 80-90 lakh in the fetus. These cells are more abundant during exercise and pregnancy.

Red blood cells are produced in the liver, spleen and thymus during the fetal stage. Produced from bone marrow (erythroblasts or stem cells and hemocytoblast cells) from birth to 20 years of age. It is called erythroblast because it has a nucleus when it is produced in the bone marrow. The rest of the life is formed from the ends of the humerus, femur, sternum, vertebrae, vertebrae etc. The human body produces 400-500 ml of red blood cells every month. Every second, 10 million red blood cells are produced and 10 million are destroyed. It is destroyed in the liver and spleen. The kidneys secrete the hormone erythropoietin. The hormone erythropoietin regulates the production (more or less) of red blood cells. The process of making red blood cells is called erythropoiesis.

1. It is red in color because it contains hemoglobin. 100 ml of blood contains 15-16 grams of hemoglobin. Each red blood cell contains 29 picograms of hemoglobin.
2. It is round, bi-concave and disk-like.
3. Its diameter is about 7.5 µm and thickness is 2.0-2.5 µm.
4. Its periphery is smooth and thick and the middle is thin. Center thickness is 1.0 µm.
5. Mammalian red blood cells do not have a nucleus (exception—camel).
6. Its average lifespan is 120 days or 4 months. During this time it covers a distance of 1100 km.
7. It contains 60-70% water and 30-40% solids (90% of the solids are hemoglobin).
8. It helps in making bilirubin and biliverdin.

The word erythrocyte is derived from the Greek words erythros meaning red and kytos meaning cell. The biconcave disk-like cells of red color of blood are called red blood cells or hematids or erythrocytes or RBCs. In the human body, red blood cells travel around the body once every 60 seconds. The body contains 20-30 trillion red blood cells which are 70% of all cells in the body. A percentage measurement of the volume of red blood cells in the blood is called hematocrit (HCT). If it is deficient in the body, it causes anemia and if it is more, it causes polycythemia. Children have the highest number of red blood cells in their blood.

Cells immersed in plasma are called blood cells. Because they do not divide, they are called granules rather than cells. The process of making blood cells is called Hematopoiesis. Blood cells make up 45% of blood. There are three types of blood cells in the body.
1. Red blood cells
2. White blood cells
3. micro cycle

1. Transport of nutrients: Amino acids, glucose, fructose, fatty acids, glycerol etc. are transported through plasma.
2. Water Transport: It regulates water transport and water balance in the body.
3. Excretion: Plasma participates in the elimination of harmful waste products produced in the body.
4. Heat balance: It regulates the heat balance throughout the body.
5. Immunity: It helps the body to resist diseases.
6. Osmotic Pressure: Plasma maintains the osmotic pressure of the blood with the help of plasma proteins.
7. Blood Coagulation: It helps in blood clotting as it contains plasma proteins.
8. Contains blood cells: It contains red blood cells, white blood cells and platelets.
9. Maintains blood fluidity: As it contains 91% water, it maintains blood fluidity.
10. Acid-base balance: Maintains blood acid-base balance.

(i) Liquid content: It contains 90%-92% water.
(ii) Inert matter: It contains 9% inert matter.
(iii) Gaseous substances: Gaseous substances are- O2, CO2, N2 etc.
(iv) Minerals: Sodium, Potassium, Calcium, Magnesium, Iron etc.
(v) Ions: Na+, K+, Ca++, Cl-, HCO3-, HPO4- etc.

(i) Nutrients: glucose, amino acids, vitamins etc.
(ii) Plasma proteins: albumin, fibrinogen, prothrombin, albumin, globulin etc. (7.5%).
(iii) Lubricants: neutral lipids, cholesterol, phospholipids, lecithin etc.
(iv) Pigments: bilirubin, biliverdin, carotene, xanthophyll etc.
(v) Organic acids: citric acid, lactic acid etc.
(vi) Excretory substances: urea, uric acid, creatinine, xanthine, ammonia etc.

The light yellow liquid part of blood is called plasma. 55% of blood is plasma. It consists of 90-92% water and 8-10% solids. There are two types of components of plasma. Organic material and inorganic material
1. organic matter
(i) Nutrients: glucose, amino acids, vitamins etc.
(ii) Plasma proteins: albumin, fibrinogen, prothrombin, albumin, globulin etc. (7.5%).
(iii) Lubricants: neutral lipids, cholesterol, phospholipids, lecithin etc.
(iv) Pigments: bilirubin, biliverdin, carotene, xanthophyll etc.
(v) Organic acids: citric acid, lactic acid etc.
(vi) Excretory substances: urea, uric acid, creatinine, xanthine, ammonia etc.
2. inorganic material
(i) Liquid content: It contains 90%-92% water.
(ii) Inert matter: It contains 9% inert matter.
(iii) Gaseous substances: Gaseous substances are- O2, CO2, N2 etc.
(iv) Minerals: Sodium, Potassium, Calcium, Magnesium, Iron etc.
(v) Ions: Na+, K+, Ca++, Cl-, HCO3-, HPO4- etc.

1. It is composed of plasma and blood cells.
2. It consists of 55% plasma and 45% blood cells.
3. Its relative importance is 1.05-1.06.
4. Its pH is 7.35-7.45 (average 7.40).
5. Temperature 36-38০C.
6. 7-8% or 12th of the total body weight is blood.
7. It is red.
8. It is highly alkaline.
9. It is salty in nature.