Name: Control and Coordination
Uploaded: 2019-07-19
Duration: 38 min 51 s
Description: There are various systems in our body that help in running it. Let's learn about our body's chemical and electrical messengers, which govern the multiple sys...

Question

Describe the histological structure of the spinal cord with a labelled diagram as shown in the transverse section.

Accepted Answer

The spinal cord is an organ of the central nervous system, which has a long and cylindrical structure that originates from the lower part of the medulla oblongata and extends to the first or second lumbar vertebrae. It is present within the vertebral canal.
Histological structure of the spinal cord: In a transverse section of the spinal cord, we can see three distinct regions of the spinal cord. At the centre, grey matter is present; at the periphery, white matter is present, and at the centre of the grey matter, a central canal is present. Two grooves penetrate the white matter of the spinal cord and divide it into right and left sides. The anterior median fissure is a deep and wide groove on the ventral (anterior) side. The posterior median sulcus is a shallow and narrow fissure that furrows on the posterior side.

Grey matter: In the spinal cord, the grey matter is centrally placed, attaining the shape of a butterfly. The grey matter comprises a mass of nerve cells and nerve fibres (both axons and dendrites and neuroglial cells). The spinal cord is divided into two symmetrical halves connected to each other by a transverse band of grey matter and is called the grey commissure in the transverse section of the spinal cord. The grey matter that lies posterior to the grey commissure is called the posterior (dorsal) horn, while that extends anteriorly is called the anterior (ventral) horn. In addition to the posterior and the anterior horns, each half of the spinal cord at the thoracic and lumbar segments contains a conical lateral expansion of the grey matter known as the lateral horn.

White matter: Outside the grey matter, a peripheral white soft substance is present called white matter. It is made up of myelinated axons of motoneurones, sensory neurones and neuroglia. Like grey matter, the white matter is also incompletely divided into two symmetrical halves. Each lateral half of the white matter is differentiated into three regions, a posterior white column (lying between the posterior root and the posterior median septum), a lateral white column (lying between the posterior and anterior root), and an anterior white column (lying between the anterior root and anterior median fissure).

Central canal: The central canal of the spinal cord exists throughout its whole length and is continuous above the fourth ventricle of the brain. Its inner surface is lined by cubical ciliated epithelium (ependyma). Cerebrospinal fluid (CSF) circulates through this canal with the help of the movement of cilia of the ciliated epithelium.

A TRANSVERSE SECTION OF THE SPINAL CORD

Describe the histological structure of the spinal cord with a labelled diagram as shown in the transverse section.

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