Lymphatic System

As blood flows through your cardiovascular system, fluid leaks out of your capillaries and mixes with the fluid that bathes your cells. Most of the fluid is reabsorbed by the capillaries, but some isn't. Your lymphatic system deals with this, it collects excess fluids and returns it to your blood. Your lymphatic system also helps fight off pathogens, which are microorganisms and viruses that make you sick.

Vessels of the Lymphatic System

The fluid that your lymphatic system collected is transported through vessels. The lymph capillaries are the smallest vessels of the lymphatic system. Lymph capillaries absorb fluid and any other particles to large to enter the blood capillaries. The particles and fluids absorbed into the capillaries are called lymph.

Lymph capillaries carry lymph into lymphatic vessels, which are larger vessels that have valves. Lymph isn't pushed by a pump, instead the squeezing of skeletal muscles provide the force to move lymph through vessels, and valves help prevent backflow. Lymph travels through your lymphatic system and then drains into large neck veins of the cardiovascular system.

Lymphatic Organs

Lymph Nodes

A lymph travels through your vessels, it passes through lymph nodes. Lymph nodes are small bean-shaped organs where particles are removed from the lymph. Lymph nodes contain many white blood cells, some of these cells engulf pathogens. Other white blood cells produce chemicals that become attached to pathogens and mark them for destruction. When the body becomes infected with bacteria or virus, the white blood cells multiply and the nodes sometimes become swollen and painful.

Thymus

Your thymus is located just above you heart, and releases white blood cells. The white blood cells travel to other areas of the lymphatic system.

Spleen

Your spleen is your largest lymph organ, and is located in the upper left side of your abdomen. The spleen filters blood and also releases white blood cells. When red blood cells are squeezed through the spleen's capillaries, the older and more fragile cells rupture. The red blood cells are broken down and sometimes reused. For this reason, the spleen can be thought of as the red-blood-cell recycling center.

Tonsils

Tonsils are located at the back of your nasal cavity, on the inside of your throat, and at the back of your tongue. They're made up of groups of lymphatic tissue. White blood cells in the tonsils defend the body against infectons. Sometimes tonsils become badly infected and must be removed.