Blood is the fluid circulating in our bodies. This fluid is mostly water and the remaining part of it contains different solid particles such as white blood cells, red blood cells, and platelets. The liquid part of blood is called plasma. Blood is technically circulating fluid pumped by the heart that carries and transports oxygen and nutrients to cells and carries away waste products and carbon dioxide.
Blood carries different hormones so that they can reach that part in the bodywhere they can exert their effects. Apart from this blood plays some vital roles in the human body’s functioning and development.
Blood Components and their functionality
Blood is made up of plasma, red blood cells, white blood cells, and platelets. These all components of blood play their roles in blood functioning importantly.
Plasma is 90 percent water and 10 percent consists of salts and proteins. The main role of plasma is that all the blood components are carried through the plasma to each part of the body. It serves as a medium of transporting and blood can perform its functions. The water part of the plasma is responsible to keep hydrated all the cells of the body. Blood plasma contains different nutrients, hormones, and proteins and takes them to different parts of the body. It takes away metabolic wastes and toxic substances from cells. Plasma helps to maintain normal blood pressure. It also helps the body to distribute the heat properly.
Red blood cells:
Red blood cells are developed in the bone marrow and come in the cellular part of the blood. They are responsible to give blood its red color, and its characteristics. Red blood cells contain a protein called hemoglobin. Hemoglobin is an oxygen-binding protein and makes red blood cells able to carry oxygen with them. Red blood cells take the oxygen from the lungs and carry it to each cell of the body and then take carbon dioxide from cells which is a metabolic waste and take it to lungs where it is excreted out from the body. The average life of a red blood cell in the human body is 100 to 120 days. In an adult man, there are 5.2 million red blood cells per cubic millimeter of blood are present.
White blood cells:
White blood cells are also known as leukocytes and are responsible for the body’s immune system. These cells don’t contain hemoglobin but capable of defending the body against infections, diseases, and foreign particles by destroying infectious agents and by producing antibodies. A healthy person’s blood contains 4500 to 1100 white blood cells per cubic millimeter of the blood. The white blood cell count varies in different conditions and situations. A higher count than normal is known as leukocytosis. And a lower count than normal is known as leukopenia. The count of white blood cells can decrease in certain conditions such as pain, infections, stress, labor, pregnancy, and certain diseases. The count can be lower in a certain type of infection or disease when associated with certain conditions such as chronic anemia and malnutrition.
Platelets are the non-nucleated cells that are only present in mammals and are
responsible for blood clotting. As compare to other cells of the blood platelets occupy a much smaller fraction of the volume of the blood. The major key function of platelets is to prevent blood loss during any injury or bleeding. When the endothelial surface of the blood vessels is injured, platelets come in large numbers at the injured site and attached themselves to the injured surface and each other and form an adherent mass of platelets. This function of platelets helps to stop bleeding by forming a blood clot. I platelets are absent this important defense reaction cannot happen.
Blood components are the same in all people but they have different blood types. Blood is classified on the basis of these types. These types were first discovered in 1901 by Karl Landsteiner an Austrian scientist. There are eight different blood groups or types and which blood group a person has totally depended on his genes.
A positive: A positive is the most common blood group. 35.7% of the US population has A
positive blood group. A positive blood donor can only donate to someone with A positive and AB positive blood group.
A negative: This is a rare type of blood. Only 6.3% of the US population has this blood group. A donor with this blood type can donate to anyone with an A or AB blood type.
B positive: This is also a rare type. 8.6% US population has it. A donor with this group can
donate to only B positive and AB positive blood group.
B negative: B negative is a very rare type of blood. Only 1.5% of the US population has this group of blood. A person with B negative blood group can donate blood to anyone with B and AB blood types.
AB positive: People with this blood type are called universal recipients because they can receive blood from any blood group.3.4% US population has this blood group.
AB negative: Here comes the rarest blood type. Only 0.6% of the US population has this group. People with this group are called the universal plasma donor because their blood plasma can be received by any blood group.
O positive: This is one of the most common blood groups. Someone with this blood group can donate to anyone with a positive blood group. 37.4% of the US population has this blood group.
O negative: People with O negative blood type are called a universal donor. Someone with this blood group can donate blood to anyone with any blood group. This blood group is rare and present in 6.6% US population. Group A has the A antigen and B antibody. Group B has a B antigen and An antibody. Group AB has both A and B antigens but neither A nor B antibodies. Group O has A and B antibodies but doesn’t have A and B antigens.
Importance of blood
The blood plays an important role in maintaining the body’s systems and homeostasis. Blood is responsible for transporting oxygen to cells, excretion of wastes, carrying hormones and other signals, regulating body’s temperature, regulating Ph of the body, generating immunity, nourishing the body with vital nutrients, and regulating the blood pressure. The bottom line is blood is essential to the body. It performs the functions that are necessary for life. Blood cannot be generated or manufactured outside the body. The only source of the blood is a blood transfusion from a generous blood donor.
Written by: Talha Ahmad (Clinical Dietitian)