3- LYMPHATIC SYSTEM

LYMPHATIC SYSTEM

• It is part of the circulatory system.
• Differences with blood circulatory:
• lymph travels through its vessels doesn´t need the action of the heart movement is unidirectional (tissues --> lymphatic vessels --> blood)
• COMPOSITION
• LYMPH : transparent liquid made of LYMPHOCYTES and INTERSTITIAL PLASMA. This plasma is formed when blood plasma is filtered when it travels to the tissues. It is collected by lymphatic capillaries (there the plasma is called LYMPH PLASMA) This plasma is carried to the blood by lymphatic veins. There is continuous exchange between blood plasma, interstitial plasma and lymph plasma.
• LYMPHATIC VESSELS : lymphatic capillaries are closed at one end and are found in tissues. They join together to make lymph veins. These lymphatic veins end when they reach blood veins. They look like a necklace made of beads , and inside they have half-moon shaped valves.
• LYMPHATIC ORGANS (spleen and thymus) and LYMPHATIC TISSUES (tonsils) : produce and mature lymphocytes and purify blood.
• LYMPH NODES : made of lymphatic tissue located in specific areas of lymphatic vessels. They make lymphocytes and release lymph plasma.
• FUNCTIONS
• Maintains the liquid balance in the internal environment.
• Plays a role in protecting the body
• Collects product from fat digestion using LACTEALS (lymphatic capillaries from in the small intestine microvilli)