The lymphatic system and circulatory system are two of the most important anatomical components of living organisms. They primarily comprise the body's waste removal and blood circulating capabilities, respectively. Some scientists believe that these two systems should both be considered part of one major system: the cardiovascular system. They are intertwined and work together to transport substances through the body. In addition, portions of the blood help create lymph, and lymph removes wasteful blood cells from the body.
Both of these systems work in a similar manner. They both produce liquid substances — blood and lymph — that move through their networks of vessels and ducts to various parts of the body. Each of these liquid substances carries nutrients or removes waste. As such, both could be considered circulatory in nature.
The circulatory system is primarily responsible for transporting blood throughout the body. It's made up of the heart, the organ that pumps blood, and the veins and arteries that move blood to and away from body tissues. Blood transport is crucial because this substance carries many nutrients and fluids that the body needs for sustenance, such as oxygen.
The lymphatic system acts as a waste removal system for the body. When unneeded material is absorbed by the muscles, lymph picks up this material and transports it to the lymph nodes, where it is ingested. Old and unusable red blood cells are eliminated in this way, meaning that the circulatory system uses the lymphatic system as a means of disposal.
Further, an individual’s lymphatic system and circulatory system work together to provide the body with lymph. This clear fluid is produced in the lymphatic system and initially carried by lymphatic vessels, where it is moved via vessel contractions. From the lymphatic vessels, lymph goes into the lymphatic ducts. After moving through these areas, it empties into the circulatory system’s subclavian veins.
The blood plays a major role in creating lymph. Blood plasma becomes a substance known as interstitial fluid when it comes into contact with body tissues. Some of this fluid enters lymphatic vessels, where it is then transformed into lymph. In fact, one of the primary responsibilities of the lymphatic system is to drain interstitial fluid from tissues.
A more unfortunate role the lymphatic system and circulatory system might work together on is the spread of cancer. Since lymphatic vessels and lymph are so prevalent in all areas of the body, this fluid will often carry cancer cells into the blood, which transports them into new bodily regions. This process is known as metastasis.
The lymphatic system is responsible for returning blood proteins and fluid back to the blood stream. Lymphedema is edema relating to the function of the lymphatic system. Edema is when fluid accumulates excessively in tissue spaces and causes the appearance of swelling.