Human Brain: Spinal Cord.
Spinal Cord.
The spinal cord is roughly cylindrical in shape,
Present in the vertebral cavity of the vertebral column.
In adults it extends from the medulla oblongata to the superior border of the second lumbar vertebra.
Its length ranges from 42-45 cm with a diameter of about 2 cm in the thoracic region.
The spinal cord is also surrounded by three spinal meninges namely.
Dura matter- Superficial layer
Arachnoid mater- Middle layer
Pia mater- Inner layer.
Spinal cord consists of 31 pairs of spinal nerves.
At the terminal end of the spinal cord the roots of the spinal nerves go inferiorly in the vertebral cavity which is collectively called as cauda equina (Horse’s tail).
The nerve which extends inferiorly up to the coccyx is called a filum terminale.
Internal Anatomy:
The cross section of the spinal cord shows H-shaped gray matter present at the centre surrounded by white matter.
A small space present in the centre of the gray matter is called the central canal which consists of CSF.
The gray matter on each side of the spinal cord is subdivided into anterior gray horns and posterior gray horns.
These gray horns divide the white matter into three areas.
Anterior white column
Posterior white column
Lateral white column
Anterior part deals with “Somatic” work.
Posterior part deals with “Autonomic” work.
Posterior horn contains a v- shaped area called “Substantia gelatinosa”.
Sensory nerves of the spinal cord consist of axons that conduct impulses towards the brain.
Motor nerves consist of axons that carry impulses from the brain to the skeletal muscles.
Spinal cord connects the brain to the sensory receptors, muscles and glands present in all parts of the body.
Commonly Asked Questions.
Write a short note on “Spinal Cord”.
Draw a well labelled diagram of T.S. of Spinal Cord.
Explain the internal anatomy of the spinal cord.
Labels: Human Anatomy and Physiology
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