Q1 of 102 Page 118

Fill in the blanks by choosing the correct alternative given for each.


(i) Brain and spinal cord are the parts of __________ nervous system (central/peripheral/autonomous)


 


(ii) __________ is the largest part of the brain. (Cerebellum/cerebrum/medulla oblongata).


 


(iii) White matter consists mainly of __________ (axons/dendrites/cytons)


 


(iv) The part of the brain concerned with body balance is __________ (cerebrum, cerebellum, medulla oblongata).

(i) Brain and spinal cord are the parts of the Central nervous system.


Explanation: The central nervous system is contained within the dorsal body cavity and is sites which control all the activity we do. The brain in the skull and the spinal cord contained within the vertebral column are parts of the central nervous system.


(ii) Cerebrum is the largest part of the brain.


Explanation: Cerebrum fills most of the upper skull and is divided into two hemispheres, left and right cerebral hemispheres. It occupies most of the brain region.


(iii) White matter consists mainly of Axons.


Explanation: White matter is composed of bundles of myelinated axons, which connect various gray matter areas of the brain to each other, and carry nerve impulses between neurons. The type of fat in myelin of axons make the white matter look white.


(iv) The part of the brain concerned with body balance is cerebellum.


Explanation: The cerebellum makes postural adjustments in order to maintain balance. Through its input from vestibular receptors and proprioceptors, it modulates commands to motor neurons to compensate for shifts in body position or changes in load upon muscles.


More from this chapter

All 102 →
1

Write one word for each of the following:


(i) The structural and functional unit of nervous system _____________


 


(ii) A wave of electrical disturbance that sweeps over the nerve cell. _____________


 


(iii) Long thread-like part of the nerve cell. _____________


 


(iv) Point of contact between two nerve cells. _____________


 


(v) A bundle of axons enclosed in a tubular sheath _____________


 


(vi) The kind of nerve carrying impulses from the brain to a gland or muscle. _____________

 2

Categorize the following under stimulus and response.


(i) Withdrawal of hand on touching a hot plate ____________


 


(ii) Seeing a green light turning red at a road crossing before applying the brakes ____________


 


(iii) Pain in the eye if something falls into it. ____________

 2

Given below are a few common reflexes in humans. Write against each the kind of reflex it is (simple or conditioned).

(i) Knee-jerk ___________


(ii) Watering of mouth on seeing a favourite dish ___________


(iii) Tying of shoelaces while talking ___________


(iv) The closing of eyelids if a strong beam of light is flashed across ___________

 3

Given alongside is a partial diagrammatic representation of a certain phenomenon pertaining to the nervous system.


(i) Name the parts numbered 1-7


(ii) What phenomenon does the diagram represent? ____________


(iii) Name the parts not shown in the diagram that should be included to complete the pathway of the phenomenon. ______________