a. Lymphatic Capillaries. Lymphatic capillaries are located in the interstitial
spaces. Here, they absorb the excess fluids.
b. Lymph Vessels. A tributary system of vessels collects these excess fluids,
now called lymph. Like veins, lymphatic vessels are supplied with valves to help
maintain a flow of lymph in one direction only. The lymphatic vessels, to a greater or
lesser extent, parallel the venous vessels along the way. The major lymph vessel in the
human body is called the thoracic duct. The thoracic duct passes from the abdomen up
through the thorax and into the root of the neck in front of the vertebral column. The
thoracic duct there empties into the junction of the left subclavian and jugular veins.
c. Lymph Nodes. Along the way, lymphatic vessels are interrupted by special
structures known as lymph nodes. These lymph nodes serve as special filters for the
lymph fluid passing through.
d. Tonsils. Tonsils are special collections of lymphoid tissue, very similar to a
group of lymph nodes. These are protective structures and are located primarily at the
entrances of the respiratory and digestive systems.