Смекни!
smekni.com

Lolo Essay Research Paper Forwards and backwards (стр. 3 из 3)

There is not just one ‘kind’ of blood. There exists the ABO blood typing. It is the variations on the molecular scale in one kind of self marker on red blood cells. The self markers are known as antibodies. People with one type of marker are said to belong to that group, either A or B if there is only one type of marker. Some people have both markers and are said to be AB blood type, while others have no markers and are type O. If someone is type A, the antibodies from that type will ignore other type A blood but attack type B. It is the same vise versa. However, type AB blood’s markers can tolerate A, B or AB blood. Type O blood has markers against all other forms. When there is a mixture of incorrect blood typing, such as A mixed with B, something called agglutination will occur. Antibodies act against foreign cells and cause clumping. If this occurs in a body, the clumps can destroy the smaller vessels and can lead to damage of tissue or death.

The lymphatic system is a has very important role to play in the body. Many people say that the lymphatic system is not a part of the circulatory system, but since it is connected to the circulatory system it will be in this case. The role of the lymphatic system is to return fluid from the body tissues to the bloodstream. This fluid when in intracellular spaces is known as interstitial fluid. It bathes and nourishes body tissue. If there was no method to remove this fluid, the surrounding tissue would become swollen and eventually burst. Some of the interstitial fluid may go back into the capillaries that have low pressure, but most of it returns through the lymphatic system. The fluid is then called lymph. It is chemically much the same as plasma. Lymph however contains half as many proteins as plasma, since larger proteins cannot seep through the capillaries.

The lymphatic system also serves as a line of defense against diseases. These harmful particles are filtered out by small masses of tissue called lymph nodes. These nodes which can vary in size from 1/25 to 1 inch. The nodes are in bunches in certain parts of the body. They are found in great numbers in the neck and armpits, above the groin, as well as close to large organs and blood vessels. In the lymph nodes are macrophages, meaning ‘big eaters’. They absorb harmful matter and tissue. The lymphatic vessels on which these are located are like blood vessels. The lymph flows from small branches to larger ones. The lymph from the upper right quarter of the body reaches the thoracic duct, which is the largest vessel of its kind. Lymph then flows upwards through the duct and into a blood vessel near the junction of the neck and right shoulder.

With this evidence of the importance of the c.