Introduction to the Lymphatic System

Lymphatic System Purposes

One of the most significant functions of the lymphatic system is maintaining fluid balanceThe maintenance of proper fluid volume and distribution in the body. within the body. The lymphatic vessels collect excess interstitial fluidThe fluid surrounding cells within tissues., which is fluid that leaks from blood vessels into surrounding tissues.

The lymphatic system is like a drainage system that transports lymph, a clear fluid containing immune cellsThe basic structural and functional units of life., throughout the body. Lymph nodes, which are small, bean-shaped structures located along lymphatic vessels, filter this fluid as it passes through. Within the lymph nodes, lymphocytes are present. These include particularly B cells and T cells. They identify and attack pathogens such as bacteria, viruses, and other foreign invaders.

Another critical function of the lymphatic system is the absorption of fats and fat-soluble vitamins from the digestive system. The small intestine contains specialized lymphatic vessels called lacteals. These vessels absorb dietary fats during digestion. They also absorb fat-soluble vitamins (A, D, E, and K). Once absorbed, these substances are transported through the lymphatic system before entering the bloodstream.  So, instead of passing through the liverA large organ that produces bile, detoxifies blood, and stores nutrients. after digestion, these items are passing through lymph nodes for cleansing.

Pathway of Lymph

Lymphatics start out really small interwoven with the blood capillary beds.  Just as venulesSmall veins that collect blood from capillaries and transport it to larger veins. join to form veinsBlood vessels that return deoxygenated blood to the heart (except pulmonary veins, which carry oxyge, lymphatic capillariesThe smallest blood vessels where gas, nutrient, and waste exchange occurs between blood and tissues. come together to form lymphatic vessels. These lymphatic vessels form lymphatic trunks. All the lymphatic trunks join together to form the lymphatic collecting ducts. These ducts dump into the subclavian veins.  However the right subclavian vein only receives lymph from the right arm

Glymphatic System of the Brain

It is only recently that we have discovered the lymphatic system of the brain.  Seriously, like less than 10 years ago we thought that there were no lymphatics in the brain.  It has lymphatic-like functions involving the spaces between the blood vessels and the neural tissue.  These spaces, called perivascular tunnels, contain CSF that is monitored by astrocytesStar-shaped glial cells in the CNS that support neurons and maintain the blood-brain barrier..  Astrocytes are taking from arteriesBlood vessels that carry oxygenated blood away from the heart (except pulmonary arteries, which carr what they need to feed the neuronsThe functional cells of the nervous system that transmit signals.. We’ve also discovered that astrocytes contribute to the blood-brain barrierA selective barrier that prevents harmful substances from entering the brain. in this additional way of monitoring the CSF.  Hey, ya discover something new every day.  I say that knowing that this discovery is probably the result of someone’s life’s work.