1. The Lymphatic System

2. The lymphatic system is a specialized component of the circulatory system. Consists of a moving fluid called lymph and a group of vessels (lymphatic vessels) that return lymph to the blood.

3. The Lymphatic System

4. Parts of the Lymphatic System –Lymph: clear, watery fluid –Lymph nodes: located along the paths of collecting vessels. –Isolated nodules of lymphatic patches in the intestinal wall (lacteals). –Specialized lymphatic organs such as the tonsils, thymus, and spleen.

5. The Lymphatic System Two main functions –Maintenance of fluid balance in the internal environment. –Immunity

6. Fluid Balance Plasma filters into the interstitial spaces from blood flowing through the capillaries. –Most of the interstitial fluid is absorbed by tissue cells or reabsorbed by the blood before it flows out of the tissue. –A small amount of interstitial fluid is left behind

7. Fluid Balance Without the lymphatic system, the increased interstitial fluid would cause massive edema (swelling due to osmosis) and cell death

8. Fluid Balance The lymphatic vessels act as "drains" to collect excess fluid and return it to the venous blood just before it reaches the heart.

9. Fluid Balance The lymphatic system differs from the circulatory system in that the lymphatics do not form a closed ring or circuit. –Blind ends in the intercellular spaces of the soft tissues of the body.

10. Fluid Balance

11. The Lymphatic System