What Are the Spleen and Lymphatic System? The spleen is located in the upper left part of the belly under the ribcage. It helps protect the body by clearing worn-out red blood cells and other foreign bodies (such as germs) from the bloodstream. The spleen is part of the lymphatic system, which is an extensive drainage network. The lymphatic (lim-FAT-ik) system works to keep body fluid levels in balance and to defend the body against infections. It is made up of a network of lymphatic vessels that carry lymph — a clear, watery fluid that contains proteins, salts, and other substances — throughout the body. What Does the Spleen Do? The spleen acts as a filter. It weeds out old and damaged cells and helps control the amount of blood and blood cells that circulate in the body. The spleen also helps get rid of germs. It contains white blood cells called lymphocytes and macrophages. These cells work to attack and destroy germs and remove them from the blood that passes through the spleen. The body also uses the spleen as a place to store blood and iron for future use. What Does the Lymphatic System Do? One of the lymphatic system's major jobs is to collect extra lymph fluid from body tissues and return it to the blood. This is important because water, proteins, and other substances are always leaking out of tiny blood capillaries into the surrounding body tissues. If the lymphatic system didn't drain the excess fluid, the lymph fluid would build up in the body's tissues, making them swell. The lymphatic system is a network of very small tubes (or vessels) that drain lymph fluid from all over the body. The major parts of the lymph tissue are located in the: bone marrow spleen thymus gland lymph nodes tonsils The heart, lungs, intestines, liver, and skin also contain lymphatic tissue. The major lymphatic vessels are: the thoracic duct: It begins near the lower part of the spine and collects lymph from the pelvis, abdomen, and lower chest. The thoracic duct runs up through the chest and empties into the blood through a large vein near the left side of the neck. the right lymphatic duct: It collects lymph from the right side of the neck, chest, and arm, and empties into a large vein near the right side of the neck. The lymphatic system also helps defend the body against germs (viruses, bacteria, and fungi) that can cause illnesses. Those germs are filtered out in the lymph nodes, small clumps of tissue along the network of lymph vessels. Inside the lymph nodes, lymphocytes called T-cells and B-cells help the body fight infection. B cells make antibodies — special proteins that stop infections from spreading by trapping disease-causing germs and destroying them. Most of our lymph nodes are in clusters in the neck, armpit, and groin area. They're also found along the lymphatic pathways in the chest, abdomen, and pelvis, where they filter the blood. When a person has an infection, germs collect in the lymph nodes. If the throat is infected, for example, the lymph nodes in the neck may swell. That's why doctors check for swollen lymph nodes (sometimes called swollen "glands") in the neck when someone has a sore throat. This is called lymphadenopathy. Back to Articles Related Articles Mononucleosis (Mono) It's sometimes called "the kissing disease," but kissing is just one of the ways that someone can catch mono. Read More Immune System The immune system is made up of special cells, proteins, tissues, and organs that defend people against germs and microorganisms. Read More Blood Find out about the mysterious, life-sustaining fluid called blood. Read More Digestive System Most people think digestion begins when you first put food in your mouth. But the digestive process actually starts even before the food hits your taste buds. Read More Strep Throat Strep throat is a common infection that usually needs to be treated with antibiotics. Find out how to recognize the signs of strep throat and what to expect if you have it. Read More Tonsillitis You wake up and your throat is swollen and you have a fever. Could it be tonsillitis? Find out what tonsillitis is, how to treat it, and how to prevent it. Read More Endocrine System The endocrine system influences almost every cell, organ, and function of our bodies. It is instrumental in regulating mood, growth and development, metabolism, and sexual function, among other things. Read More Bones, Muscles, and Joints Our bones, muscles, and joints form our musculoskeletal system and enable us to do everyday physical activities. Read More Note: All information is for educational purposes only. For specific medical advice, diagnoses, and treatment, consult your doctor. © 1995-2021 KidsHealth®. All rights reserved. Images provided by The Nemours Foundation, iStock, Getty Images, Veer, Shutterstock, and Clipart.com.