NCERT Class 11-Biology: Chapter –21 Neural Control and Coordination Part 3

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Question 10:

Which sensory organ is involved in vertigo (sensation of oneself or objects spinning around)?

Answer:

The vestibular system of the inner ear is associated with vertigo.

The symptoms of dizziness and vomiting are experienced by the person when he goes on higher altitudes because sudden elevation in height causes disturbance in maintaining pressure by Eustachian tube.

Question 11:

While travelling at a higher altitude, a person complains of dizziness and vomiting sensation. Which part of the inner ear is disturbed during the journey?

Answer:

The vestibular system of the inner ear is associated with vertigo.

The symptoms of dizziness and vomiting are experienced by the person when he goes on higher altitudes because sudden elevation in height causes disturbance in maintaining pressure by Eustachian tube.

Question 12:

Complete the statement by choosing appropriate match among the following –

Chapter 21- Question 12 - Table of Choosing the Correct Answer
Chapter 21- Question 12 - Table of Choosing the Correct Answer

a.

Resting potential

i.

Chemicals involved in the transmission of impulses at synapses.

b.

Nerve impulse

ii.

Gap between the pre synaptic and post synaptic neurons

c.

Synaptic cleft

iii.

electrical potential difference across the resting neural membrane

d.

Neurotransmitters

iv.

an electrical wave like response of a neuron to a stimulation.

Answer:

(a) (iii), (b) (iv), (c) (ii), (d) (i)

Short Answer Type Questions

Question 1:

The major parts of the human neural system is depicted below. Fill in the empty boxes with appropriate words.

Human neural system

Human Neural System

Human neural system

Answer:

The Human Neural System is divided into two parts Central Neural System (CNS) and Peripheral Neural System (PNS).

The CNS is further divided into Brain (which has three parts – fore brain, mid brain and hind brain) and Spinal Cord and PNS is divided into Somatic Neural System and Autonomic Neural System (divided into sympathetic neural system).

Question 2:

What is the difference between electrical transmission and chemical transmission?

Answer:

Electrical Transmission and Chemical Transmission
Electrical transmission and chemical transmission

Electrical Transmission

Chemical Transmission

(i) Impulses are sent in the form of electric potential

(i) Impulses are sent through chemicals

(ii) Signals in the neural system are sent through this

(ii) Signals in the hormonal system are sent through this

(iii) It is fast in action

(iii) It is slow in action

Question 3:

Neural system and computers share certain common features. Comment in five lines. (Hint: CPU, input-output devices).

Answer:

In computers, the input devices are mouse and keyboard while in neural system, the sensory neurons act as input devices which take inputs from the environment.

The message from input devices is sent to the brain in neural system and to the CPU in computers.

The CPU processes the information and gives command to the output devices i.e. monitor and printer. The brain processes the information from the input devices.

The brain commands the concerned organs accordingly. This is done with the help of motor neurons which act as the output devices in neural system.

Question 4:

If someone receives a blow on the back of neck, what would be the effect on the person’s CNS?

Answer:

If someone receives a blow on the back of the neck, it may lead to the dislocation of cervical vertebrae (located right below the skull). The injury of spinal cord may pass to the neural canal which can result in paralysis or severe damage to the emotional behaviour.

Question 5:

What is the function ascribed to Eustachian tube?

Answer:

The Eustachian tube is the tube that connects middle ear cavity with the pharynx.

It helps in equalising the pressure on either sides of the ear drum. There is a valve present at the pharyngeal opening. This usually remains closed. It opens up during yawning, swallowing, or due to abrupt change in altitude to let the air enter or leave the tympanic cavity to equalise the pressure.

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