The Lymphatic and Immune Systems – Immune System Example

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"The Lymphatic and Immune Systems" is a wonderful example of a paper on the immune system.   The human body faces continuous threats posed by the external as well as its internal environment. To save itself from these threats and to maintain a steady-state of health, the body has developed various  defense  systems that work in close coordination. With the help of their components, these systems counter the agents that are harmful and foreign to the natural body habitat.     Webster’ s medical dictionary defines immunity as the ability of the body to resist an infection or disease.

The foreign substances invading the body are known as antigens. The response of the body to the invading agent can either be specific or  nonspecific. The nonspecific immune response is unable to differentiate among different types of invading organisms and counters all of them in the same way. Skin acts as the first line of  defense  as it is the mechanical barrier that hinders the entry of any foreign substance in the body. The mucous membranes and stomach acid provide similar mechanical barriers. If the antigens enter inside the body, then the body responds to these foreign molecules by activating an immune response.

The cells of  nonspecific  immune systems circulate in the bloodstream and include phagocytes, natural killer cells, mast cells, and eosinophils. The body also puts up various other  nonspecific  responses to counter the threats. These responses include fever, inflammation, and the release of chemical substances like interleukins and interferons. The complement system is yet another arm of the  nonspecific  immune system (Martini, Frederic, et al, 2007). Phagocytes are the first line of  defense  at the cellular level and remove invading agents in peripheral tissues by engulfing them.

Mast cells rescue the body from allergic reactions by releasing histamine. Eosinophils are activated against the parasitic invasion of the body.     The specific immune response, on the other hand, is a targeted response against a  particular invading  agent and varies from one invading organism to another. It is formed by the Lymphatic system, which comprises of lymphatic fluid (lymph), lymphatic vessels, lymphoid tissues or organs, and the lymphatic cells (B- lymphocytes and T- lymphocytes). The lymphatic tissues in various locations in the body produce lymphocytes, which circulate in the blood as well as lymphatic vessels and target the antigens that they are formed in response to.

These cells confer two different types of immune responses. T cells provide the cell-mediated immunity which counters the harmful pathogens inside the cells. B lymphocytes on the other hand give antibody-mediated immunity, which protects against the antigens in body fluids. A  particular type of invading  organism activates T as well as B lymphocytes. T cells are activated after exposure to an antigen. The activated T cells also play a role in the activation of B cells, which then produce antibodies (Guyton et al, 2000).

These antibodies, that are formed against a  particular antigen  are then released into the bloodstream and attack the invading cells or molecules.   Despite the differences in the steps of activation and levels of response put forward by each of these systems, they work in coordination in a graded manner to protect the body and  maintain it in a healthy state.  

References

Guyton, Arthur C, and John E. Hall. Textbook of Medical Physiology. Philadelphia: Saunders, 2000. Print.

Martini, Frederic, Edwin F. Bartholomew, and William C. Ober. Essentials of Anatomy & Physiology. San Francisco: Pearson/Benjamin Cummings, 2007. Print.

Merriam-webster's Medical Dictionary. Bt Bound, 2006. Print.

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