Friday, April 22, 2022

Neural Control and coordination | Class 11 | Previous Years Questions and Answers (2015 to 2020)

 NEURAL CONTROL & COORDINATION

2020 MARCH


1.     Observe the diagram. (Score 3)

a)   Name the parts A & B.

b)   Write the characteristics features of ‘C’.

c)   Arrange the given parts of eye in the sequence that light travels from the external environment into the eye.

(Vitreous chamber, lens, cornea, retina, Aqueous chamber)


Answer:

(a) A= Lens, B= Optic nerve

(b) Macula lutea (yellow spot)- thinned out part of retina.

(c) Cornea → Aqueous chamber → Lens → Vitreous chamber → Retina.


2019 JULY


1. Which of the part of brain control respiration and gastric secretions? (Score 1)
(a) Cerebrum                     (b) Cerebellum
(c) Medulla                        (d) Hypothalamus


Answer:

(c) Medulla


2. Distinguish between the following: (Score 2)
(a) Electric synapse and Chemical synapse.
(b) Rods and cones.


Answer:

(a) Electric synapse: The membranes of pre- and post-synaptic neurons are nearer. Faster impulse transmission.

Chemical synapse: There is a fluid filled space (synaptic cleft) between the presynaptic neuron and postsynaptic neuron.

(b) Rods: Helps in twilight (scotopic) vision.

Cones: Helps in daylight (photopic) vision & colour vision.


3. Prepare a flow chart showing the parts of human brain, by using the details given below: (Score 3)

Cerebrum, Medulla, Mid brain, Thalamus, Pons, Corpora quadrigemina, Hypothalamus, Forebrain, Cerebellum, Hind brain, Brain.


Answer:


2019 MODEL


1.   a) Identify the below stages of nerve impulse conduction.
(b) Name the ions involved in this process.
(c) How RMP is maintained?
(Score 3)



Answer:

(a) (1) Stage of resting membrane potential (RMP).

      (2) Stage of Depolarisation.

(b) Na+ and K+ ions.

(c) The RMP is maintained by the active transport of ions by the Na-K pump. It transports 3 Na+ outwards for 2 K+ into the cell. As a result, the outer surface becomes positively charged and inner surface becomes negatively charged.


2018 AUGUST


1. Complete the flow chart given below: (Score 3)



Answer:

(a) Spinal cord

(b) Midbrain

(c) Corpora quadrigemina

(d) Thalamus

(e) Pons

(f) Medulla oblongata


2018 MARCH


1.  The innermost eyeball is ......... (Score 1)
a) Choroid    b) Iris     c) Retina     d) Sclera


Answer:

(c) Retina


2. Complete the given flow chart. (Score 2)


Answer:

(a) Peripheral Neural System

(b) Spinal cord

(c) Autonomic Neural system

(d) Parasympathetic


2018 MODEL


1.  Redraw the diagram. Name and label the parts indicated below: (Score 3)



A - External layer of the eye ball.
B - Part where cones are densely packed.


Answer:

(A) Sclera

(B) Yellow spot (macula lutea/ Fovea)


2.   In…(a) type of synapse the membranes of pre-synaptic and post synaptic neurons are in very close proximity
In…(b)... type of synapse the membrane of pre synaptic and post synaptic neurons are separated by a fluid filled space.
a) Name the type of synapse A and B.
b) Name the fluid filled space in the synapse B.
(Score 2)


Answer:

(a) A= Electrical synapse       B= Chemical synapse

(b) Synaptic cleft.


2017 JULY (IMPROVEMENT)


1.   Nerve impulse transmission include generation and propagation of action potential. Write various stages or events in the generation of action potential. (Score 3)

Answer:

1. Maintenance of resting membrane potential

In a resting neuron, concentration of K+ and –vely charged proteins in axoplasm is high and concentration of Na+ is low.

The fluid outside the axon contains low concentration of K+ and high concentration of Na+. This forms an ionic or concentration gradient across resting membrane.

The ionic gradients are maintained by the active transport of ions by the Na-K pump. It transports 3 Na+ outwards for 2 K+ into the cell. As a result, the outer surface becomes positively charged and inner surface becomes negatively charged.

The electrical potential difference across the resting plasma membrane is called resting potential.

2. Action Potential

When a stimulus is applied, the membrane at the site A becomes permeable to Na+. This causes rapid influx of Na+ and reversal of the polarity at that site. It is called depolarization.

The electrical potential difference during depolarization across the plasma membrane is called action potential.

3. Propagation of action potential

At sites ahead (site B), outer surface is positive and inner surface is negative. As a result, a current flows on the inner surface from A to B.

On the outer surface, current flows from site B to site A to complete the circuit. Hence, the polarity is reversed and action potential is generated at site B. i.e., action potential at site A arrives at site B.

OR

2.  Observe the diagram and construct a flow chart to show the mechanism of transmission of nerve impulse across a chemical synapse. (Score 3)

Answer:

Impulse transmission through chemical synapse:

Impulse reaches at axon terminal → synaptic vesicles bind on plasma membrane → release of neurotransmitter → It diffuses across synaptic cleft → combine with receptors on the post synaptic membrane → opening of ion channels allowing entry of ions → generates action potential.


2017 MARCH


1.     Answer the following:

a)   Cerebral hemispheres of human brain are connected by ...................

i)      association area           

ii)     corpus callosum          

iii)    corpora quadrigemina

iv)    pons varolii (Score 1)

b) Observe the diagram and label A, B, C & D.    (Score 2)

Answer:

(a) ii) corpus callosum

(b) A= Axon

    B= Synaptic vesicle

    C= Synaptic cleft

     D= Neurotransmitters

2016 SEPTEMBER (IMPROVEMENT)

1.   Fovea of Retina of eye contains………. (Score 1)

a.   Rod cells only

b.   Cone cells only

c.   Both Rods and cones

d.   Rods and cones are absent

Answer:

(b) Cone cells only

2.  a) Complete the given table. (Score 2)

(Parts of Human brain)

Fore brain

Hind brain

Parts

Parts

i) Cerebrum

i) Pons

ii) Thalamus

ii) ..................

iii) ...................

iii) Medulla

b) Which one of the above parts of brain that controls gastric secretion?

Answer:

(a) ii) Cerebellum      iii) Hypothalamus

(b) Medulla

2016 MARCH


1. Observe the diagram carefully and answer the following questions.        (Score 3)

a)    Label the parts marked as A, B, C, D.

b)   Identify the photoreceptor cells present in the human eye.

Answer:

(a) A= Lens, B= Iris, C= Cornea, D= Optic nerve.

(b) Cones and rods.

2015 SEPTEMBER (IMPROVEMENT)


1.     Where do you find the following structures in human body? (Score 1)

a.      Cochlea                      b.   Neurotransmitters


Answer:

(a) Ear (Inner ear)

(b) Chemical synapse/ Synaptic vesicle

2.     Mention the functions of the following structures in human body. (Hint: Any two each). (Score 2)

a.      Hypothalamus           b.   Axon


Answer:

(a) Regulates temperature, thirst, hunger and emotions.

     Controls pituitary gland.

(b) Axon transmits impulses away from the cell body. Transmits information to different neurons, muscles, and glands.

2015 MARCH


1.     a) Prepare a pathway of an action by using following hint.

[Hint: Receptor, Motor neuron, Afferent neuron, Efferent neuron, Interneuron in the spinal cord, Effector organ]

b) Give an example of such an action. (Score 3)


Answer:

(a) Receptor → Afferent neuron → Interneuron in the spinal cord → Motor neuron → Efferent neuron → Effector organ

(b) Withdrawal of the hand when it touches a hot object, Knee jerk phenomenon etc.


OR


Compare rods and cones of the retina based on the following features. (Score 3)

i)     Shape          

ii)   Type       

iii)   Ability to detect colour

iv)   Pigments     

v)   Vision


Answer:


Features

Cones

Rods

Shape

Conical

Cylindrical

Type

3 types

1 type

Ability to detect colour

Yes

No

Pigments

Photopsin

Rhodopsin

Vision

Photopic vision

Twilight vision

 

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