June 26, 2015

Blood - Properties and its Contents - Explained

Whole blood makes up about 7% of a person's body weight. The cellular elements of blood determine its categorization as red or white blood cells, or as platelets. The fluid element is known as blood plasma. This plasma is composed of water, proteins, hormones, vitamins, amino acids, lipids, carbohydrates and inorganic salts. Next to water, which comprises 90 percent of its composition, the most important elements in blood plasma are the three blood plasma proteins: albumins, globulins, and fibrinogen. The salts present in plasma include sodium, potassium, calcium, magnesium, chloride, and bicarbonate. These salts function in many important body processes. For instance, calcium functions in muscle contraction; sodium, chloride, and potassium function in nerve impulse transmission in nerve cells; and bicarbonate regulates pH. These salts are also called electrolytes.
• Blood is a fluid connective tissue.
• Its quantity is 6.8 litres in man and 500 ml less in woman.
• Constitutes 6-8% of body weight and has a pH of 7.4.
Red Blood Corpuscles (RBCs)
• Also called erythrocytes, disc-shaped, no nucleus, contains a pigment called Haemoglobin, which gives blood its red color and transports oxygen and carbon dioxide.
• Manufactured in Red Bone marrow.
• Life is of 120 days. 
• No. of RBCs is 4.5-5 million/cubic mm. of blood.

• Also called leucocytes, rounded, with a nucleus and far less numerous than RBCs (8,000 per cubic mm. of blood). 
• Manufactured in Red Bone marrow.
• Act as the soldiers of body’s defence system.Hemoglobin contains iron which combines with oxygen to give hemoglobin and our blood, a red color.

• Also called thrombocytes and are about 2,50,000 per cubic mm. of blood.Platelets help blood clot in order to limit bleeding when your skin is cut. Blood clots can occasionally have negative effects, if they form in blood vessels going to the brain they can cause a stroke while clotting in a blood vessel going to the heart can lead to a heart attack.
• Manufactured in Red Bone marrow.

• It is a blood antigen found in RBC.
• A person can be Rh+ or Rh–depending upon the presence of Rh factor in RBC.
• Avery important point is Rh+ can receive blood from both Rh+ and Rh– but Rh– can receive blood from Rh– only.
• In world population, Rh+ are 85% and Rh are 15%.
• Blood transfusion technique was developed by James Blundell.

What Proteins Are in Blood Plasma?
Albumin makes up the largest proportion of blood plasma proteins. Albumin is manufactured by the liver and is responsible for keeping the fluid pressure level constant in the blood, so that blood continually flows in the bloodstream rather than seeping into surrounding tissues. Albumin also functions as a carrier, binding specific molecules in the blood plasma so that it can carry nutrients and vitamins where they are needed in the body.
Although globulins make up a smaller proportion of blood plasma protein, they perform the very important function of providing antibodies. Globulin protein is actually subdivided into four major categories: gamma globulin, alpha-1 globulin, alpha-2 globulin, and beta globulin. Gamma globulins are also classified as immunoglobulin and are the specific group of plasma protein that functions as antibodies providing protection against disease on a cellular level. The alpha and beta globulins primarily act as transporters for fat soluble vitamins, hormones and lipids. The alpha and beta globulins are synthesized in the liver; gamma globulins, however, are created by the lymphoid tissue.
Fibrinogen is also created by the liver. Its primary function is to work with blood platelets to create blood clots. Abnormally low levels of fibrinogen can lead to excessive bleeding and hemorrhaging.

Blood Pressure
The heart squeezes the blood and pushes it through the blood vessels. Your blood pressure is the force that the blood exerts against the walls of veins and arteries as it moves through them. Blood pressure is measured using a sphygmomanometer. The top number is known as the systolic number and the bottom number is known as the diastolic number. Normal is considered 120/80. If the numbers are higher than this guideline, then the person is said to have high blood pressure or hypertension. Repeated low readings are called hypotension



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