The immune system and nervous system are connected in a few known ways. These two seemingly different systems of the body interact with each other more often than most people know. Adrenal glands are one common link. Chemicals and hormones that are produced by cells of the two systems are another connection. Additionally, research has shown that the brain has the ability to use nerve cells to communicate directly with the immune system.
On their own, the immune system and nervous system have two different functions. The immune system is responsible for protecting the body from bacteria, viruses, and other foreign pathogens that try to invade. The nervous system relays information to the brain from the whole body, allowing movement, speech, and organ function. Due to the difference in these two systems, a connection between them would not generally seem likely.
Adrenal glands are known for the hormones they produce in response to stress. These hormones trigger the body’s release of stored energy. Corticosteroid hormones also have the ability to affect white blood cells and antibodies. Although the adrenal glands are not part of the immune system, they link these systems together because the hormones produced affect both systems.
Neuropeptides are a type of hormone that nerve cells release. Along with other hormones and chemicals, their function is to carry messages to organs and other cells in the nervous system. These chemicals and hormones also link the immune system and nervous system because they can also pass messages to cells of the immune system. Additionally, lymphokines such as interleukins have the ability to relay information from the immune system to the nervous system.
Research has shown the brain connects the immune system and nervous system as well. The brain may use nerve cells to send messages directly to the immune system to trigger an immune response. Scientists have discovered networks of nerve fibers connected to bone marrow, the spleen, and a few other organs in the body. In addition, the cells of the immune system may also be able to send messages about foreign antigens to the brain. From there, the brain can signal the nervous system to react. It is also likely that the brain uses these signals to guide nervous system cells to locations throughout the body where they are needed to help immune responses.
Although a few connections have been discovered between the immune system and nervous system, there could be many more that are still undiscovered. Functions of the body still hold many mysteries, especially with these two systems. Continuous research is an important part of discovering links between these systems.