Introduction:
The blood volume in the body varies according to size of individual. The blood accounts for about 7 percent of the body weight. The Blood is an intricate part of the Circulatory System. It tries to keep the body in an equilibrium state. The body systems are always changing the balance of the blood. Its major function is to transport all the vital substances necessary to maintain bodily life processes.
Each cell must receive oxygen and nutrients if cell life is to be maintained. The oxygen and nutrients the cells use to carry out their functions produce waste that must be removed. The blood also transports hormones from the different glands located throughout the body. These hormones act as messengers that depended on the blood for travel. Another function is to help us keep immune from disease that may enter the body. If you ever been cut thank your blood for its ability to clot. The clotting process not only stops you from bleeding to death, but also assists in stopping microbes from entering and causing infection.
To learn more about the blood use the diagram of the blood above. Click on the labels of the blood components and learn more about their functions. After viewing this page and the other pages on this site you may wish to take a quiz an see how much you have learned about the Circulatory System.
Plasma
Plasma makes up a little more than 50 percent of the blood. The composition of blood is 90 percent water and 10 percent dissolved substance. The color of Plasma is like the color straw. Plasma contains thousands of different substances like proteins, glucose, salts, vitamins, hormones, and antibodies. Plasma is what keeps the blood flowing.
Red Blood Cells:
The red blood cells are also known as erythrocytes. The red blood cells have a unique appearance. They have been described as looking like a donut because they are thinner in the center and thicker around the edges. They are very flexible with the ability to twist and bend through the blood vessels. The red blood cells are only 1/25,000 of an inch in size.
A major function of the red blood cells is to carry oxygen to all the tissues from the lungs. The red blood cells than transport the carbon dioxide from the cells because of breaking down the nutrients
The reason the erythrocytes are known as red blood cells is because of a substance called hemoglobin. Hemoglobin is composed of simple protein and iron pigments and when combined with oxygen their color becomes a bright scarlet.
Red blood cells are made in the red bone marrow. In infants every bone in their body produces red blood cells. In the adult the red blood cells can be produced in the thoracic bones, vertebrae, cranial bone and ends of femur and humerus bones. Red blood cells only live for approximately 120 days. The blood contains about 25 trillion red blood cells and has to replace them at about 3 million per second. If for some reason there is a red blood cell deficiency a problem called anemia can arise.
White Blood Cells
The white blood cells are also known as leukocytes. They defend the body against bacteria and other enemies. The name white blood cells can be very misleading. The white blood cells are colorless. White blood cells come in many varieties. Each fights the body enemies in a different way. Some white blood cells produce antibodies, detoxify foreign substances, and digest bacteria.
White blood cells are formed in the the red bone marrow, lymphatic tissue, spleen, lymph nodes, and thymus. The white blood cells are less numerous than the red blood cells and larger than red blood cells. Compared to the red blood cells the white blood cells number only 1 white blood cell to 700 red blood cell.
The life span of white blood cells varies depending on the service they have to perform. They travel throughout the circulatory system to sites that they are needed.
Platelets
Platelets are also known as thrombocytes. They are small fragments of cells that clump together and stick to inner surface of blood vessels to plug up leaks. The platelets release a substance for clotting of blood. The platelets cause the injured site to shrink and seal off. Platelets have a life span of 5 to 9 days.
The platelets are formed in the bone marrow.The number of platelets fall between the number of white blood cells and red blood cells. The number of platelets can be between 250,000 and 350,000 in normal volume of blood. The platelets get their name from their shape. They look like oval plates.
Cardiovascular System
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