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प्रश्न
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?
उत्तर
(i)
1. Sensory or Afferent fiber.
2. The cell body of the sensory neurons.
3. White matter.
4. The cell body of the motor neurons.
5. Spinal nerve.
(ii) BCA
(iii) Synapse.
(iv) Simple reflex: It is an involuntary automatic, quick response to a stimulus.
Examples:
(a) The closing of the eyelids when a strong beam of light is flashed.
(b) The withdrawal of the hand when it is pricked.
(v) In spinal cord white matter is outside and gray matter is inside. In brain white matter is inside and gray matter is outside.
APPEARS IN
संबंधित प्रश्न
Distinguish between the following pair of words:
Cranial nerve and spinal nerve
Where is this located?
Meninges
Where is this located?
Ganglia
Give the functions of the spinal cord?
Give Technical Term:
The fluid which fills the central canal of the spinal cord.
There are ______ pairs of cranial nerves and ______ pairs of spinal nerves.
______ connects the brain to a different part of the body through nerves.
Explain the formation of a typical spinal nerve with the help of a neat labelled diagram.
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.
Mention where in the human body is the following located and state its main function:
Central canal
