The blood is a fluid connective tissue. It consists of liquid plasma and
cells. The plasma makes up 55% of the total volume and 45% of cells or
formed elements. The total blood volume in human female is about 4-5 litres
and 5-6 litres in males.
Plasma :- The blood plasma is a slightly alkaline fluid. It is straw coloured.
Composition of plasma
Components Functions
1. Water - as a slovent and suspending medium for blood components.
2. Plasma proteins- Albumin - Osmotic pressure. Globulins - Antibody formation Fibrinogen - Blood clotting.
3. Ions - Na, K, Ca, Mg, Cl2, - Osmosis, acid-base balance.
Fe, PO , H and HCO3- buffer etc.,
4. Nutrients - Glucose, amino - source of energy, building blocks acids, triglycerides, cholesterol, - enzyme activity. vitamins.
5. Waste products - Urea, uric - excreted by the kidneys. acid creatinine, ammonia
Bilirubin - breakdown product of erythrocytes
Lactic acid - product of anaerobic respiration.
6. GasesOxygen - for aerobic respirationCO2- waste product of respirationNitrogen - inert gas.
7. Regulating substances Hormones and Enzymes - body functions
Blood cells or formed elements
There are three types of blood cells or corpuscles. They are
1. Red Blood Corpuscles (RBC) or Erythrocytes
These are circular, biconcave and non-nucleated cells. Males haveabout 5.2 million erythrocytes per cubic millimeter of blood (range : 4.2-5.8million). Females have about 4.5 million/mm3 (range 3.6-5.2 million).
Each disc shaped RBC is about 7.5 mm in diameter. Their main component is a pigmented protein, haemoglobin. It gives red colour to the blood. The haemoglobin transports O2. The oxygenated form of
haemoglobin is called oxyhaemoglobin. Erythrocytes stay in circulation for about 120 days in males and 110
days in females. They are manufactured in the marrow of bones such as ribs and vertebrae. They disintegrate in the spleen and liver.
2. White Blood Corpuscles (WBC) or Leucocytes
These are clear cells lacking haemoglobin. They are nucleated cells exhibiting amoeboid movement. They protect the body against invading micro-organisms and remove dead cells from the body. There are five types of leucocytes.
a). Neutrophils - These are the most common type of leucocytes (60-70%) in the blood. Their nuclei can occur in more than one form. Hence they are called polymorphonuclear neutrophils (PMN).
b). Eosinophils (0.5-3.0%) - They are motile cells that leave the circulation to enter the tissues during an inflammatory reaction. During allergy reaction their number increases.
c). Basophils (0.1%) - They play a role in allergic and inflammatory reaction. They contain heparin which inhibits blood clotting.
d). Lymphocytes (20-30%) - These are smallest leucocytes. They are more common in lymphatic tissues namely the lymph nodes, spleen, tonsils and thymus. Lymphocytes, called B-cells can produce proteins called antibodies that can get attached to the bacteria and destroy them. T-cells. protect us against viruses by attacking and destroying cells in which viruses are reproducing.
e). Monocytes (1-4%) - These are largest leucocytes. They destroy bacteria, dead cells and cell fragments. During chronic infection their number increases.
3. Blood Platelets or Thrombocytes
These are minute fragments of cells that play a very important role in coagulation of blood. Their life expectancy is 5-9 days.
cells. The plasma makes up 55% of the total volume and 45% of cells or
formed elements. The total blood volume in human female is about 4-5 litres
and 5-6 litres in males.
Plasma :- The blood plasma is a slightly alkaline fluid. It is straw coloured.
Composition of plasma
Components Functions
1. Water - as a slovent and suspending medium for blood components.
2. Plasma proteins- Albumin - Osmotic pressure. Globulins - Antibody formation Fibrinogen - Blood clotting.
3. Ions - Na, K, Ca, Mg, Cl2, - Osmosis, acid-base balance.
Fe, PO , H and HCO3- buffer etc.,
4. Nutrients - Glucose, amino - source of energy, building blocks acids, triglycerides, cholesterol, - enzyme activity. vitamins.
5. Waste products - Urea, uric - excreted by the kidneys. acid creatinine, ammonia
Bilirubin - breakdown product of erythrocytes
Lactic acid - product of anaerobic respiration.
6. GasesOxygen - for aerobic respirationCO2- waste product of respirationNitrogen - inert gas.
7. Regulating substances Hormones and Enzymes - body functions
Blood cells or formed elements
There are three types of blood cells or corpuscles. They are
1. Red Blood Corpuscles (RBC) or Erythrocytes
These are circular, biconcave and non-nucleated cells. Males haveabout 5.2 million erythrocytes per cubic millimeter of blood (range : 4.2-5.8million). Females have about 4.5 million/mm3 (range 3.6-5.2 million).
Each disc shaped RBC is about 7.5 mm in diameter. Their main component is a pigmented protein, haemoglobin. It gives red colour to the blood. The haemoglobin transports O2. The oxygenated form of
haemoglobin is called oxyhaemoglobin. Erythrocytes stay in circulation for about 120 days in males and 110
days in females. They are manufactured in the marrow of bones such as ribs and vertebrae. They disintegrate in the spleen and liver.
2. White Blood Corpuscles (WBC) or Leucocytes
These are clear cells lacking haemoglobin. They are nucleated cells exhibiting amoeboid movement. They protect the body against invading micro-organisms and remove dead cells from the body. There are five types of leucocytes.
a). Neutrophils - These are the most common type of leucocytes (60-70%) in the blood. Their nuclei can occur in more than one form. Hence they are called polymorphonuclear neutrophils (PMN).
b). Eosinophils (0.5-3.0%) - They are motile cells that leave the circulation to enter the tissues during an inflammatory reaction. During allergy reaction their number increases.
c). Basophils (0.1%) - They play a role in allergic and inflammatory reaction. They contain heparin which inhibits blood clotting.
d). Lymphocytes (20-30%) - These are smallest leucocytes. They are more common in lymphatic tissues namely the lymph nodes, spleen, tonsils and thymus. Lymphocytes, called B-cells can produce proteins called antibodies that can get attached to the bacteria and destroy them. T-cells. protect us against viruses by attacking and destroying cells in which viruses are reproducing.
e). Monocytes (1-4%) - These are largest leucocytes. They destroy bacteria, dead cells and cell fragments. During chronic infection their number increases.
3. Blood Platelets or Thrombocytes
These are minute fragments of cells that play a very important role in coagulation of blood. Their life expectancy is 5-9 days.
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