Microscopic lymphatic capillaries are the ones that create the beginning of what is known as the lymphatic system. It is these lymphatic capillaries which are close-ended tubular formations that create large and intricate networks within the intercellular spaces of most of our body’s tissue. One example of this would have to be within the villi within our small intestines. It is here that the lymphactic capillaries are known as lacteals and will be used for the transportation of any products which have been generated by fat absorption away from the GI tract. The endothelial cells make up the inner walls of the capillaries, which are porous, absorbed fats, interstitial fluid, proteins, and microorganisms which are able to enter these capillaries without having to exert much effort. Once any kind of fluid begins its journey within the capillary walls, it will then be known as lymph fluid. Whenever there is oversaturation of interstitial fluid within the capillaries, it will lead to a medical condition known as edema, which is the result of poor drainage of the lymph fluid.
Lymph fluids will travel through the smaller capillaries and will then combine and flow into the larger vessels called lymph ducts. The inner walls of these lymph ducts are much like the inner walls of our veins. They are designed very similarly except for the valves which are there to prevent back flow; they also have the same three layers which the walls of the veins are composed of. It is the skeletal muscles and their tendency to contract which results in a massaging motion which generates the friction necessary for the lymph fluid to be able to flow about continuously throughout the network. Intestinal movement as well will contribute to this motion and so does the occasional peristaltic action of our lymphatic vessels. The valves keep our lymph fluids flowing in the right direction. It is the job of our lymph ducts to constantly connect and then interconnect until they at last empty out into of the two main vessels. The thoracic duct is bigger than the right lymphatic duct and drains the lymph fluid which has been received in our lower extremities, the left thoracic area, the abdominal region, left upper extremity, and the left side of our neck and head. The main section of this vessel will then follow the spinal column until it drains directly to the subclavian vein.
Our thoracic duct has an enlargement which is similar to a sac located within our abdominal region. This is known as the cistern chilli and it is its job to collect our lymph fluid from the intestinal area and lower extremities. Our right lymphatic duct is smaller and it is its job to drain the lymphatic fluid from the right side of our neck and head, our right upper extremity and our right thoracic region. Our right lymphatic duct will then drain all the collected lymph fluid and flush it into our subclavian vein which is near our jugular vein.