Tag: neural control and coordination

In cross-section, the peripheral region of the cord contains neuronal white matter tracts containing sensory and motor neurons. Internal to this peripheral region is the grey matter.

The dorsal root or the posterior root is the main bundle of nerve fibers that branch off from the spinal cord to enter other areas of the body. This combines with the ventral root to form the spinal nerve. and becomes the afferent sensory root and is responsible for carrying and transmitting the sensory information from the body to the brain for processing the signals by the brain. If the dorsal root is broken, then the transfer of information will not be possible. Thus, the correct answer is option D.

The spinal cord is the extension of the medulla oblongata that runs down through the foremen of magnum. The lowest part of the spinal cord is narrow and it is called the conus medullaris. The conus medullaris is present at the L$ _{1}$ vertebrae. The terminal part of the conus medullaris is a thread-like structure that is made up of fibrous connective tissue called the filum terminale. It is the non-nervous part of the spinal cord that can be seen in the lumbar vertebrae.

A unipolar neuron is a type of neuron in which only one protoplasmic process (neurite) extends from the cell body. A pseudounipolar neuron is a kind of sensory neuron in the peripheral nervous system. This neuron contains an axon, that has split into two branches; one branch runs to the periphery and the other to the spinal cord.

The spinal cord is a thick cord of the nervous tissue that forms the central nervous system along with the brain. It extends from the brain down through the spine and is protected within the bony vertebral column which is made of bones called the vertebrae. It ends at the second lumbar vertebrae. It is divided into the regions according to the vertebral column as cervical, thoracic and lumbar. The bunch of nerve fibres at the end of the spinal cord is called the cauda equina. It forms a horse tail-like structure. The nerves from this region supply to the pelvic region and lower limbs.

A dorsal root ganglion (or spinal ganglion) (also known as a posterior root ganglion), is a cluster of nerve cell bodies (a ganglion) in a posterior root of a spinal nerve.
The cell bodies of peripheral neurons are often found grouped into clusters called ganglia. On the basis of the type of nerve cell bodies found in ganglia, they may be classified as either sensory or motor. Sensory ganglia are oval swellings located on the dorsal roots of spinal nerves and on the roots of certain cranial nerves.

The fourth ventricle present between the brainstem and the cerebellum is called the metacoel. It continues to the spinal cord in the form of the central canal to form the cavity of the spinal cord filled with the cerebrospinal fluid. The central canal is also called the neurocoel.