Question

The diagram given below depicts the cross section of the spinal cord Study the same and then answer the Questions that follow:

(i) Name the process that is being depicted. 

(ii) Name the parts labelled 2, 5, and 6. 

(iii) Name the cells in contact with the part labelled ‘1’. 

(iv) What is the function of the parts labelled 3, 4 and 7 ? What is the technical term given to the pathway represented by 3, 4, and 7 ? 

(v) How does the arrangement of cells in the spinal cord differ from that in the brain ?

Answer 1

(i ) The process’depicted by this diagram is ‘Reflex Action’. 

(ii) Part 2 — Dorsal Root Ganglion Part 5 — Central Canal. Part 6 — Gray Matter. 

(iii) The cells in contact with the part labelled ‘1’ is Receptor cells. 

(iv) Functions of the parts labelled 3, 4 and 7 are as follows : 

Part 3 — Afferent (Sensory) nerve fibre carry the stimulus from receptor organ to the spinal cord. 

Part 4 — (Synapse) point between sensory and motor neuron. It is a place where incoming sensory impulse generates an outgoing motor impulse. 

Part 7 — ( Effect neuron) : It carries away the impulse generated by the association neuron in the centre to the effector organ (muscle or gland). Technical term given to the pathway represented by 3, 4 and 7 is ‘Reflex Arc’. 

(v) In spinal cord, the gray matter lies on the inner side and the white matter lies on the outer side This arrangement is just reversed in the brain.