ICSE 2018: The diagram given below shows the internal structure of a spinal cord depicting a phenomenon.

ICSE 2018 

Q. The diagram given below shows the internal structure of a spinal cord depicting a phenomenon. Study the diagram and answer the questions: [5]

(i) Name the phenomenon that is depicted in the diagram. Define the phenomenon. 

(ii) Give the technical term for the point of contact between the two nerve cells. 

(iii) Name the parts numbered 1, 2 and 3. 

(iv) How does the arrangement of neurons in the spinal cord differ from that of the brain? 

(v) Mention two ways by which the spinal cord is protected in our body.

Solution:

This 5 marks question based on the Spinal Cord and was asked by ICSE board in the year 2018 in SECTION-II. 

The question tested the knowledge of students on the: 

• What is Reflex Action?
• What is Synapse?
• Internal Structure of Spinal Cord
• Functions of Spinal Cored

Let's begin with solving the above mentioned questions:

i) The phenomenon depicted the diagram is Reflex Action.

Reflex action is an automatic, quick and involuntary action in the body brought about by a stimulus.

ii) The point of contact between two serves is called Synapse.

iii) The parts numbered 1,2,3 are:

    1: Sensory neuron

    2: Motor neuron

    3: Gray matter

iv) The arrangement of neurons in the spinal cord differ from that of the brain as the gray matter containing cell bodies of motor (efferent) and association neurons lies on the inner side and the white matter on the outer side.

v) Two ways through which spinal cord is protected in our body are:

    1. Externally spinal cord is covered by three membranes - dura matter, arachnoid and pia matter.

    2. Central canal of spinal cord is filled with cerebrospinal fluid which acts as shock absorber.