Biology

Neural Control and Coordination

Question:

Answer briefly.
(a) How do you perceive the colour of an object?
(b) Which part of our body helps us in maintaining the body balance?
(c) How does the eye regulate the amount of light that falls on the retina?

Answer:

(a)In humans, colour vision results from the activity of cone cells, a type of photoreceptor cells. In the human eye, there are three types of cones which possess their own characteristic photopigments that respond to red, green and blue lights. The sensations of different colours are produced by various combinations of these cones and their photopigments. When these cones are stimulated equally, sensation of white light is produced. Yellow light, for instance, stimulates green’and red cones approximately to equal extent, and this is interpreted by the brain as yellow colour.
(b) Ears (cristae and maculae present in internal ears).
(c) The iris contains two sets of smooth muscles – sphincters and dilators. These muscles regulate the amount of light entering the eyeball by varying the size of pupil. Contraction of sphincter muscles makes the pupil smaller in bright light so that less light enters the eye. Contraction of dilator muscles widens the pupil in dim light so that more light goes in eye to fall on retina.

previuos
next

Neural Control and Coordination

Q 1.

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

Q 2.

Label the following parts in the given diagram using arrow.
(a) Aqueous chamber
(b) Cornea
(c) Lens
(d) Retina
(e) Vitreous chamber
(f) Blind spot
ncert-exemplar-class-11-biology-solutions-neural-control-and-coordination-6

Q 3.

Comment upon the role of ear in maintaining the balance of the body and posture.

Q 4.

Which cells of the retina enable us to see coloured objects around us?

Q 5.

Answer the following.
(a) Which part of the ear determines the pitch ofa sound?
(b) Which part of the human brain is the most developed?
(c) Which part of our central neural system acts as a master clock?

Q 6.

Complete the statement by choosing appropriate match among the following.
ncert-exemplar-class-11-biology-solutions-neural-control-and-coordination-4

Q 7.

The major parts of the human neural system is depicted below. Fill in the empty boxes with appropriate words.
ncert-exemplar-class-11-biology-solutions-neural-control-and-coordination-2

Q 8.

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

Q 9.

Name the structures involved in the protection of the brain.

Q 10.

Name the parts of human forebrain indicating their respective functions.

Q 11.

Rearrange the following in the correct order of involvement in electrical impulse movement- Synaptic knob. Dendrites, Cell body. Axon terminal. Axon.

Q 12.

Explain the following.
(a) Role of Na+ in the generation of action potential.
(b) Mechanism of generation of light-induced impulse in the retina.
(c) Mechanism through which a sound produces a nerve impulse in the inner ear.

Q 13.

What do grey and white matter in the brain represent?

Q 14.

6. Give a brief account of
(a) Mechanism of synaptic transmission.
(b) Mechanism of vision.
(c) Mechanism of hearing.

Q 15.

Arrange the following in the order of reception and transmission of sound wave from the ear drum:
Cochlear nerve.External auditoru canal, Ear drum, Stapes, Incus, Malleus, Cochlea.

Q 16.

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?

Q 17.

Explain the following.
(a) Role of Na+ in the generation of action potential.
(b) Mechanism of generation of light-induced impulse in the retina.
(c) Mechanism through which a sound produces a nerve impulse in the inner ear.

Q 18.

What is the function ascribed to Eustachian tube?

Q 19.

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

Q 20.

The region of the vertebrate eye, where the optic nerve passes out of the retina, is called the
(a) fovea (b) iris
(c) blind spot (d) optic chiasma
 

Q 21.

Our reactions like aggressive behaviour, use of abusive words, restlessness etc. are regulated by brain, name the parts involved.

Q 22.

Briefly describe the structure of the following:
(a) Brain (b) Eye (c) Ear

Q 23.

Write short notes on the following:
(a) Neural coordination (b) Forebrain
(c) Midbrain                       (d) Hindbrain
(e) Retina                             (f) Ear ossicles
(g) Cochlea                          (h) Organ of Corti
(i) Synapse

Q 24.

Compare the following:
(a) Central neural system (CNS) and Peripheral neural system (PNS).
(b) Resting potential and action potential.
(c) Choroid and retina.

Q 25.

Where is the hunger centre located in human brain?

Q 26.

Answer briefly.
(a) How do you perceive the colour of an object?
(b) Which part of our body helps us in maintaining the body balance?
(c) How does the eye regulate the amount of light that falls on the retina?

Q 27.

Explain the following processes:
(a) Polarisation of the membrane of a nerve fibre.
(b) Depolarisation of the membrane of a nerve fibre.
(c) Conduction of a nerve impulse along a nerve fibre.
(d) Transmission of a nerve impulse across a chemical synapse.

Q 28.

Explain the structure of middle and internal ear with the help of diagram.

Q 29.

Explain the process of the transport and release of crneurotransmitter with the help of a labelled diagram showing a complete neuron, axon terminal and synapse.

Q 30.

Distinguish between
(a) Afferent neurons and efferent neurons
(b) Impulse conduction in myelinated nerve fibre and unmyelinated nerve fibre
(c) Aqueous humour and vitreous humour
(d) Blind spot and yellow spot
(e) Cranial nerves and spinal nerves

Q 31.

During resting potential, the axonal membrane is polarised, indicate the movefnent of +ve and -ve ions leading to polarisation diagrammatically.

Q 32.

Draw labelled diagrams of the following:
(a) Neuron (b) Brain
(c) Eye (d) Ear

Q 33.

What is the difference between electrical transmission and chemical transmission?

Q 34.

Differentiate between
(a) Myelinated and non-myelinated axons
(b) Dendrites and axons
(c) Rods and cones
(d) Thalamus and Hypothalamus
(e) Cerebrum and Cerebellum