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प्रश्न
Explain the formation of a typical spinal nerve with the help of a neat labelled diagram.
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उत्तर
Formation of Spinal Nerve
- All spinal nerves are of the mixed type i.e. they have some nerve fibre as sensory and some motor.
- Each spinal nerve is formed inside the neural canal of vertebral column by two roots - the posterior or dorsal sensory root and anterior or ventral root.
- Anterior root receives the sensory nerve from the dorsal root ganglion (cell bodies of sensory neurons are located in the ganglion), while the anterior/ventral root gives out the motor nerve.
- The dorsal sensory and the ventral motor nerves together form the mixed spinal nerve.
- It emerges out from both sides of the spinal cord through the intervertebral foramen.
- As soon as it emerges out of vertebral column, it shows three branches viz.
- Ramus dorsalis: From skin and to muscles of dorsal side.
- Ramus ventralis: The largest of the three supplies the organs and muscles on lateral and anterior side.
- Ramus communicans: The smallest of the three and given out from 1st thoracic upto 3rd lumbar (L3) spinal nerve. It joins the sympathetic ganglia.
APPEARS IN
संबंधित प्रश्न
Where is this located?
Meninges
Give one point of difference between the following on the basis of what is indicated:
Cerebrum and spinal cord. (Arrangement of neurons)
Spinal cord and sympathetic ganglion of autonomous nervous system are connected by ______________.
Give Technical Term:
The fluid which fills the central canal of the spinal cord.
The diagram given below shows the internal structure of the spinal cord, depicting a simple reflex. Study the same and then answer the questions that follow:
(i) Name the parts numbered 1 to 5.
(ii) Using the letters of the alphabet shown in the figure indicate the direction in which an impulse enters and leaves the spinal cord.
(iii) What is the term given to the point of contact between two nerve cells?
(iv) What is meant by ‘simple reflex’ ? Give two examples of simple reflexes and name the stimuli too.
(v) How does the arrangement of nerve cells in the spinal cord differ from that in the brain?
Mention, if the following statement is True or False
Spinal nerves are twelve pair
Which neuron conducts impulse from the spinal cord to the effector organ?
Spinal cord is enclosed in ____________ of vertebral column.
Spinal nerves are usually ______
Given below is the transverse section of the spinal cord. Read the information below the diagram and fill in the blanks:
The spinal cord extends from the medulla oblongata of the brain and runs down through the whole length of the vertebral column. The spinal cord is covered by the meninges. It conducts impulses from the skin and muscles to the brain. It also conducts impulses from the brain to the muscles of the trunk and limbs.
The spinal cord is a part of the (a) ______ Nervous System. The grey matter in the picture given above consists of (b) ______ while the white matter consists of (c) ______. The spinal cord is concerned with the (d) ______ actions below the neck. (e) ______ is the bony structure that protects the spinal cord.
