According on the book; Gray’s anatomy, lymph is a clear watery, fluid contained in a system of vessels almost as passive as those for the blood. The lymph is then finally emptied into the blood stream by special communications at the junctions of the jugular and subclavian veins at both sides of the neck without communicating to the blood vessels. The lymphatic system consists of the following: (1) an extensive capillary network which collects lymph in the various organs and tissues; (2) it is an elaborate system of collecting vessels which carry the lymph from the lymphatic capillaries to the blood stream, opening into the great veins at the root of the neck; (3) a number of firm rounded bodies called lymph nodes which are placed like filters in the paths of the collecting vessels; (4) certain lymphatic organs which resemble the lymph nodes, that is, tonsils and solitary or aggregated lymphatic nodules; (5) the spleen and (6) the thymus (Gray, 735).
Another book entitled Essentials of human anatomy and physiology, they indicated that the lymphatic system actually consists of two semi-independent parts: (1) a meandering network of lymphatic vessels and (2) various lymphoid tissues and organs scattered throughout the body. The function of the lymphatic vessels is to pick up the excess tissue fluid now called lymph or clear water and return it to the blood steam. The lymphatic vessels also called as lymphatics, form a one way system, and lymph flows only toward the heart. Lymph is transported from the lymph capillaries through successively larger lymphatic vessels, referred to as lymphatic collecting vessels, until it is finally returned to the venous system through one of the two large ducts in the thoracic region. Lymphatic vessels are thin-walled, and the larger ones have valves, is a low pressure but pumpless system (Marieb, 368-369)
Lymph nodes and other lympoid organs
In the named Life Science, lymph nodes are clusters of pea-sized structures at the intervals of lymphatic system. These nodes acts as a sieves that filters out and destroys bacteria, toxins and dead cells that are removed from the tissues by the lymph. Each node has a fibrous outer covering enclosing a mass of material called lymphoid tissue that contains defensive white blood cells called macrophages that break down foreign particles (Cavendish, 483).
There are many lymphoid organs in our body and lymph nodes is just one of an example of many types of it. And in the book Teaching health science: elementary and middle school identified four. Tonsils, found just beneath the epithelium of the mouth and throat, and include the palatine, pharyngeal and lingual tonsils. Second is the thymus, this gland is usually comprised of two lobes, and plays a key role in the formation of antibodies in the first few weeks of life, and the development of the immunity. It is located at the base of the neck and it manufactures lymphocytes. Another one is the spleen, situated in the left abdomen next to the stomach and designed to filter blood and produce lymphocytes that carry on phagocytosis and has many functions concerned with the lymphatic and blood circulation. An the last one is the lymph node that filters and removes bacteria (Bender Et. Al., 375).
In the book entitled Essentials of human anatomy and physiology specified two body defenses; specific and nonspecific body defenses. The nonspecific body defense system responds immediately to protect the body from all foreign substances, whatever they are while the specific body defense system also commonly called the immune system, mounts the attack against particular foreign substances. The nonspecific has two lines of defenses, the first line are the skin and mucous membranes, and the second line are the cells and chemicals that rely on the destructive powers of phagocytes and natural killer cells, the inflammatory response and a variety of chemical substances that kill pathogens and help repair tissue. The nonspecific body defense or the immune system eliminates with nearly equal precision almost any type of pathogen that intrudes into the body and also increases the inflammatory response and provides protection that is carefully targeted against specific antigens and also referred to as the third line of body defense (Marieb, 372-379).
In the book Essentials of human anatomy and physiology, Antibodies is also referred to as immunoglobulin or Igs, constitute the gamma globulin part of blood proteins and are soluble proteins secreted by activated B cells or by their plasma-cell offspring in response to an antigen and are capable of binding specifically with that antigen. Each of an antibody has basic structure formed with four amino acid chains linked together by sulfide. When these four chains are combined it forms into a two identical halves that each contains a heavy and light chain and a molecule as a whole is a T- or Y- shaped. There are five major immunoglobulin classes – IgM, IgA, IgD, IgG, and IgE. Monomers are Y in structure like IgD, IgG, and IgE antibodies, while dimmer is a two linked monomers, antibody IgA is both monomer and dimmer. Pentamers are antibody with five linked monomers like antibody IgM. Each antibodies of each class have slightly different biological roles and locations in the body and IgG is the most abundant antibody in blood plasma and is the only type that can cross the placental barier. Antibodies play an important role in our body like complement fixation, neutralization, agglutination and precipitation. Of these complement fixation and neutralization are most important to body protection (Marieb, 385-387).
Works Cited Page
Marieb, Elaine N. Essentials of Human Anatomy and Physiology. San Francisco, CA: Pearson Education Inc, 2004.
Gray, Henry. Gray’s Anatomy. Philadelphia: Lea and Febiger, 1969.
Cavendish, Marshall. Exploring life Sciences. New York: Marshall Cavendish Corporation, 2000.
Bender, Stephen, Neutens, James, Hardin-Skonie, Selene, and Sorochan, Walter D. Teaching Health Science: Elementary and Middle School. Sadbury, MA: Jones and Barlett Publishers, 1997.