The Lymphatic System: Form and Function

Tim ZimmerClub Newsletter

The Lymphatic System of the living body is a fascinating and integral part of our living wellness. Our understanding of this system has deepened profoundly over the last couple decades as major advancements have been made in our understanding of the immune system and how our body maintains health.

The Lymphatic System has two main functions. It maintains the fluid balance within the body’s extracellular tissue spaces, and it houses our immune system, otherwise known as our Lymphoid system.

The Lymphatic system consists of lymphatic vessels, lymph nodes, and primary lymph fluid collection and reabsorption sites/organs. Lymphatic vessels are located throughout the body within all tissue, muscle, and organ spaces. They travel along and between the veins and arteries, collecting fluid and transporting immune cells, within the capillary beds. These capillary beds are where are body’s smallest vessels exchange nutrients and gases, such as oxygen and carbon dioxide, with our body’s tissues and cells.


The Lymph fluid itself is a clear, watery substance whose composition depends entirely on the interstitial fluid composing it. It is much like blood plasma, and will carry proteins, the immune response cells of the lymphoid system, and general waste products and toxins found present in our tissues and between our cells.

Organs of the Lymphatic and Lymphoid system include; the bone marrow, the thymus gland, the spleen, the lymph nodes, the mucosal associated lymphoid tissue (M.A.L.T.) found in the intestine, the tonsils, and the appendix.

Understanding the Lymphatic system becomes simpler when we are able to compare it to body systems which are similar and possibly more familiar to us. For example, the Lymphatic System is like the Circulatory system in many ways; it is located throughout the body, it moves fluid throughout the body, it has a number of organs of functional importance, and it serves as a very delicate and effective delivery system.

Unlike the Circulatory system, the lymph vasculature is not a closed circuit and does not have a pump, therefore it is not pressurized. The Lymph vessels are plentiful, thin-walled, and begin blindly within the interstitial tissue space, and are closed at one end. The lymph vessels are lined with numerous valves that keep the lymph moving in one direction and against gravity. The lymph is moved slowly throughout the body by the contractions that occur during respiration and by the larger muscle contractions that occur during movement, such as Exercise!

Lymph fluid is brought to the tissue spaces by the arteries, through the blood. Arteries become capillaries who release fluid and nutrients into the tissue spaces for the cells. As fluid and gas exchange occurs within the capillary space, not all the fluid is returned to the capillaries. This fluid accumulates in the tissues as interstitial fluid or lymph fluid. The Lymph fluid moves from the tissues into the lymph vessels and travels to lymph nodes located throughout the body. From the lymph nodes, lymph fluid from the lower limbs and abdomen drain into a small lymph sac/collection vessel called the Cisterna Chyli, which lies deep behind the aorta, against the first lumbar vertebrae. Lymph fluid then travels up the Thoracic duct, ascending the vertebral column, and is reintroduced into the venous system via the left Thoracic duct, draining it into the left subclavian vein. The Lymph fluid originating from the right arm and right upper chest and head drain into the right thoracic duct on the right subclavian vein. Lymph fluid re-enters the main fluid circulation in this way.

A fascinating fact – deep belly breathing moves lymph along more effectively and quickly than shallow or chest breathing. It has to do with the compression of the Cisterna Chyli (the lymph collection sac in your abdomen), that occurs during inspiration and contraction of the diaphragm. The second best way to move lymph is exercise, so keep on moving, and stay hydrated. Summer is here.

By Dr. Kimberly Free, ND