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Gray Commissure
The grey commissure is a thin strip of grey matter that surrounds the central canal of the spinal cord and, along with the anterior white commissure The anterior white commissure (ventral white commissure) is a bundle of nerve fibers which cross the midline of the spinal cord just anterior (in front of) to the gray commissure (Rexed lamina X). A delta fibers (Aδ fibers) and C fibers carryin ..., connects the two halves of the cord. It comprises lamina X in the Rexed classification. External links * Spinal cord {{neuroscience-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Grey Matter
Grey matter is a major component of the central nervous system, consisting of neuronal cell bodies, neuropil (dendrites and unmyelinated axons), glial cells (astrocytes and oligodendrocytes), synapses, and capillaries. Grey matter is distinguished from white matter in that it contains numerous cell bodies and relatively few myelinated axons, while white matter contains relatively few cell bodies and is composed chiefly of long-range myelinated axons. The colour difference arises mainly from the whiteness of myelin. In living tissue, grey matter actually has a very light grey colour with yellowish or pinkish hues, which come from capillary blood vessels and neuronal cell bodies. Structure Grey matter refers to unmyelinated neurons and other cells of the central nervous system. It is present in the brain, brainstem and cerebellum, and present throughout the spinal cord. Grey matter is distributed at the surface of the cerebral hemispheres (cerebral cortex) and of the cerebellu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Central Canal
The central canal (also known as spinal foramen or ependymal canal) is the cerebrospinal fluid-filled space that runs through the spinal cord. The central canal lies below and is connected to the ventricular system of the brain, from which it receives cerebrospinal fluid, and shares the same ependymal lining. The central canal helps to transport nutrients to the spinal cord as well as protect it by cushioning the impact of a force when the spine is affected. The central canal represents the adult remainder of the central cavity of the neural tube. It generally occludes (closes off) with age. Structure The central canal below at the ventricular system of the brain, beginning at a region called the obex where the fourth ventricle, a cavity present in the brainstem, narrows. The central canal is located in the third of the spinal cord in the cervical and thoracic regions. In the lumbar spine it enlarges and is located more centrally. At the conus medullaris, where the spinal co ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Spinal Cord
The spinal cord is a long, thin, tubular structure made up of nervous tissue, which extends from the medulla oblongata in the brainstem to the lumbar region of the vertebral column (backbone). The backbone encloses the central canal of the spinal cord, which contains cerebrospinal fluid. The brain and spinal cord together make up the central nervous system (CNS). In humans, the spinal cord begins at the occipital bone, passing through the foramen magnum and then enters the spinal canal at the beginning of the cervical vertebrae. The spinal cord extends down to between the first and second lumbar vertebrae, where it ends. The enclosing bony vertebral column protects the relatively shorter spinal cord. It is around long in adult men and around long in adult women. The diameter of the spinal cord ranges from in the cervical and lumbar regions to in the thoracic area. The spinal cord functions primarily in the transmission of nerve signals from the motor cortex to the body, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Anterior White Commissure
The anterior white commissure (ventral white commissure) is a bundle of nerve fibers which cross the midline of the spinal cord just anterior (in front of) to the gray commissure (Rexed lamina X). A delta fibers (Aδ fibers) and C fibers carrying pain sensation in the spinothalamic tract contribute to this commissure, as do fibers of the anterior corticospinal tract, which carry motor signals from the primary motor cortex. Two of the five sensory modalities, pain and temperature, cross sides at the anterior white commissure, reaching the contralateral side about two vertebral levels rostral to their origin. The spinothalamic tract thus decussates very soon after entering the spinal cord, ascending in the spinal cord, contralateral to the side from where it provides (pain and temperature) sensory information. Therefore, a lesion that is caudal to the sensory decussation where the remaining 3/5 modalities decussate (at the superior medulla) will result in contralateral (opposite s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Rexed Lamina
The Rexed laminae comprise a system of ten layers of grey matter (I–X), identified in the early 1950s by Bror Rexed to label portions of the grey columns of the spinal cord. Similar to Brodmann areas, they are defined by their cellular structure rather than by their location, but the location still remains reasonably consistent. Laminae * Posterior grey column: I–VI ** Lamina I: marginal nucleus of spinal cord or posteromarginal nucleus ** Lamina II: substantia gelatinosa of Rolando ** Laminae III and IV: nucleus proprius ** Lamina V: Neck of the dorsal horn. Neurons within lamina V are mainly involved in processing sensory afferent stimuli from cutaneous, muscle and joint mechanical nociceptors as well as visceral nociceptors. This layer is home to wide dynamic range tract neurons, interneurons and propriospinal neurons. Viscerosomatic pain signal convergence often occurs in this lamina due to the presence of wide dynamic range tract neurons resulting in pain referral. ** Lam ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
