Brain Cells Found Elsewhere
Brain cells, specifically neurons and their variants, are not exclusive to the central nervous system (CNS). While the majority of neurons reside in the brain and spinal cord, some types of neurons and their precursors can be found in other parts of the body. Here are some examples:
- Dorsal Root Ganglion (DRG) Neurons: These neurons are found in the peripheral nervous system (PNS) and transmit sensory information from the skin and other tissues to the spinal cord. They are similar to central neurons but have distinct characteristics.
- Enteric Neurons: Located in the gastrointestinal tract, these neurons form the enteric nervous system (ENS), which regulates gut function, such as motility, secretion, and blood flow. Enteric neurons are often referred to as “little brain” due to their complexity and autonomy.
- Sympathetic and Parasympathetic Neurons: These neurons are part of the autonomic nervous system (ANS) and are found in various organs, including the heart, lungs, and gastrointestinal tract. They regulate involuntary functions, such as heart rate, blood pressure, and digestion.
- Sensory Neurons: Some sensory neurons, like those responsible for pain and temperature sensation, are found in the PNS and transmit information to the spinal cord or brain.
- Neural Crest Cells: These cells, derived from the neural tube, migrate to various parts of the body and give rise to diverse cell types, including neurons, glia, and melanocytes. They are found in tissues such as the skin, cartilage, and bone.
- Peripheral Glial Cells: While not neurons, peripheral glial cells, like Schwann cells and satellite cells, support and maintain the function of peripheral neurons.
These brain cells or their variants found elsewhere in the body play crucial roles in regulating various physiological processes, such as:
- Sensory perception and processing
- Autonomic function and homeostasis
- Gut motility and secretion
- Immune response and inflammation
- Development and maintenance of tissues and organs
Understanding the distribution and functions of brain cells outside the CNS is essential for comprehending the complex interactions between the nervous and non-nervous systems.