The Importance Of The Lymphatic System

Introduction
The ability to ward off disease is called immunity (resistance). Lack of resistance is called
Susceptibility. The two general types of immunity are innate and adaptive. Innate immunity refers to a wide variety of body responses to a wide range of pathogens. Adaptive immunity involves activation of specific lymphocytes to combat a particular foreign substance.
2. Lymphatic System Structure and Function
1. The lymphatic system carries out immune responses and consists of lymph, lymphatic vessels, and structures and organs that contain lymphatic tissue (specialized reticular tissue containing many lymphocytes). The lymphatic system drains interstitial fluid, transports dietary lipids, and protects against invasion through immune responses. Lymphatic vessels begin as closed-ended lymphatic capillaries in tissue spaces between cells. Interstitial fluid drains into lymphatic capillaries, thus forming lymph. Lymphatic capillaries merge to form larger vessels, called lymphatic vessels, which convey lymph into and out of lymph nodes. The route of lymph flow is from lymphatic capillaries to lymphatic vessels to lymph trunks to the thoracic duct (left lymphatic duct) and right lymphatic duct to the subclavian veins. Lymph flows because of skeletal muscle

The skin and mucous membranes are the first line of defense against entry of pathogens. Antimicrobial substances include interferons, the complement system, iron-binding proteins, and antimicrobial proteins. Natural killer cells and phagocytes attack and kill pathogens and defective cells in the body. Inflammation aids disposal of microbes, toxins, or foreign material at the site of an injury, and prepares the site for tissue repair. Fever intensifies the antiviral effects of interferons, inhibits growth of some microbes, and speeds up body reactions that aid