A drug that blocks only neurotransmitter receptors on post-synaptic membranes is added to a preparation that has both electrical and chemical synapses. Which result is expected?

Transmission stops at chemical synapses but continues at electrical ones

Transmission continues at both kinds, since release of transmitter is not affected

Transmission stops at electrical synapses but continues at chemical ones

Transmission stops at both kinds, since both types depend on neurotransmitter

An electrode placed inside an axon shows that the inner surface turns positive at a stimulated site. Which event directly causes this reversal?

Action of the sodium-potassium pump

Exit of negatively charged proteins

Neural Control and Coordination

22 NEET-UG practice questions on Neural Control and Coordination, part of Zoology. The first 22 are below; the first 5 with answers and explanations (tap Show answer after you have chosen), the rest in Learn with a free account.

Question 1 · Medium
Match List-I with List-II. List-I (brain structure) A. Corpus callosum B. Thalamus C. Hypothalamus D. Corpora quadrigemina List-II (feature) I. Major coordinating centre for sensory and motor signalling II. Tract of nerve fibres connecting the two cerebral hemispheres III. Four round swellings on the dorsal midbrain IV. Control of body temperature and the urge for eating and drinking
1. AA-III, B-I, C-IV, D-II
2. BA-II, B-I, C-IV, D-III
3. CA-I, B-II, C-IV, D-III
4. DA-II, B-IV, C-I, D-III
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Answer: B · A-II, B-I, C-IV, D-III
The corpus callosum connects the two hemispheres. The cerebrum wraps around the thalamus, the coordinating centre for sensory and motor signalling. The hypothalamus controls body temperature and the urge for food and drink, and the corpora quadrigemina are four swellings on the dorsal midbrain.
- A: This swaps the corpus callosum and the corpora quadrigemina.
- C: This swaps the corpus callosum and the thalamus.
- D: This swaps the thalamus and the hypothalamus.
Remember this
Thalamus relays and coordinates; hypothalamus controls temperature, eating and drinking; corpus callosum links hemispheres.
Question 2 · Easy
Which part of the human brain contains the centres that control respiration, cardiovascular reflexes and gastric secretions?
1. AThalamus
2. BPons
3. CMedulla
4. DCerebellum
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Answer: C · Medulla
The medulla is connected to the spinal cord and contains centres that control respiration, cardiovascular reflexes and gastric secretions. Together with the midbrain and pons, it forms the brain stem.
- A: The thalamus is a major coordinating centre for sensory and motor signalling.
- B: The pons consists of fibre tracts that interconnect different regions of the brain.
- D: The cerebellum is noted for a convoluted surface with very many neurons.
Remember this
Medulla controls breathing, cardiovascular reflexes and gastric secretion; pons has fibre tracts linking brain regions.
Question 3 · Hard
A drug that blocks only neurotransmitter receptors on post-synaptic membranes is added to a preparation that has both electrical and chemical synapses. Which result is expected?
1. ATransmission continues at both kinds, since release of transmitter is not affected
2. BTransmission stops at electrical synapses but continues at chemical ones
3. CTransmission stops at chemical synapses but continues at electrical ones
4. DTransmission stops at both kinds, since both types depend on neurotransmitter
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Answer: C · Transmission stops at chemical synapses but continues at electrical ones
At a chemical synapse the signal crosses the synaptic cleft only when released neurotransmitter binds post-synaptic receptors, so the drug stops it. At an electrical synapse the membranes are in very close proximity and current flows directly from one neuron to the next, with no receptor involved.
- A: Release alone is not enough, as the transmitter must bind its receptor to open ion channels.
- B: This reverses which synapse depends on receptors.
- D: Electrical synapses use direct current flow, not neurotransmitter.
Remember this
Chemical synapses need neurotransmitter and receptors; electrical synapses pass current directly and are faster.
Question 4 · Medium
An electrode placed inside an axon shows that the inner surface turns positive at a stimulated site. Which event directly causes this reversal?
1. AAction of the sodium-potassium pump
2. BExit of negatively charged proteins
3. CRapid efflux of K⁺
4. DRapid influx of Na⁺
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Answer: D · Rapid influx of Na⁺
A stimulus makes the membrane at that site freely permeable to Na⁺. The rapid inflow of Na⁺ reverses the polarity, so the inner surface turns positive and the outer surface negative. This depolarised state is the action potential.
- A: The pump maintains the resting gradients and does not make this sudden reversal.
- B: The axoplasm's negatively charged proteins cannot cross the membrane.
- C: K⁺ efflux comes later and restores the resting polarity.
Remember this
Na⁺ influx depolarises; the later K⁺ efflux repolarises the membrane.
Question 5 · Medium
Which of the following statements about neurons are correct? A. Nissl's granules are present in the cell body. B. Synaptic knobs contain vesicles filled with neurotransmitter. C. Dendrites carry impulses away from the cell body. D. Bipolar neurons are found in the cerebral cortex. Choose the correct answer.
1. AA and D only
2. BA, B and C only
3. CA and B only
4. DA, B and D only
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Answer: C · A and B only
The cyton holds the cytoplasm with Nissl's granules, and the synaptic knobs hold synaptic vesicles with neurotransmitters, so A and B are correct. Dendrites carry impulses towards the cell body, so C is wrong. Bipolar neurons are found in the retina and multipolar ones in the cerebral cortex, so D is wrong.
- A: This rejects B and accepts D.
- B: This accepts C, which reverses the direction of conduction in dendrites.
- D: This accepts D, which places bipolar neurons in the cortex instead of the retina.
Remember this
Dendrites bring impulses in, axons carry them out; multipolar in cortex, bipolar in retina.
Question 6 · Easy
Arrange the following in order from the skull inward to the brain tissue. A. Arachnoid B. Cerebral cortex C. Pia mater D. Dura mater Choose the correct order.
1. AD, A, C, B
2. BA, D, C, B
3. CC, A, D, B
4. DD, C, A, B
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Question 7 · Medium
Given below are two statements: Statement I: At rest, the axonal membrane is more permeable to K⁺ than to Na⁺. Statement II: The sodium-potassium pump moves 3 Na⁺ into the axon for every 2 K⁺ it moves out. Choose the correct answer.
1. AStatement I is incorrect but Statement II is correct
2. BBoth Statement I and Statement II are incorrect
3. CStatement I is correct but Statement II is incorrect
4. DBoth Statement I and Statement II are correct
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Question 8 · Medium
Given below are two statements: Statement I: An unmyelinated nerve fibre is enclosed by a Schwann cell that does not form a myelin sheath around the axon. Statement II: The gaps between two adjacent myelin sheaths on an axon are called synaptic clefts. Choose the correct answer.
1. AStatement I is incorrect but Statement II is correct
2. BBoth Statement I and Statement II are correct
3. CBoth Statement I and Statement II are incorrect
4. DStatement I is correct but Statement II is incorrect
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Question 9 · Hard
A stimulus makes site A of a resting axon depolarised, while site B just ahead of it is still polarised. In which directions does local current flow between the two sites?
1. AFrom A to B on the inner surface, and from B to A on the outer surface
2. BFrom B to A on both the inner and outer surfaces
3. CFrom B to A on the inner surface, and from A to B on the outer surface
4. DFrom A to B on both the inner and outer surfaces
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Question 10 · Easy
The two cerebral hemispheres of the human brain are connected by a tract of nerve fibres called the
1. Apons
2. Bcerebral aqueduct
3. Ccorpus callosum
4. Dcorpora quadrigemina
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Question 11 · Medium
Match List-I with List-II. List-I (part of brain) A. Pons B. Cerebellum C. Corpora quadrigemina D. Limbic system List-II (feature) I. Very convoluted surface that gives space for many more neurons II. Four round swellings on the dorsal side of the midbrain III. With the hypothalamus, regulates emotional reactions and sexual behaviour IV. Fibre tracts that interconnect different regions of the brain Choose the correct answer.
1. AA-II, B-I, C-IV, D-III
2. BA-IV, B-I, C-II, D-III
3. CA-IV, B-I, C-III, D-II
4. DA-I, B-IV, C-II, D-III
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Question 12 · Hard
Read these statements about the human brain. A. The cerebral cortex is called grey matter because of the concentration of neuron cell bodies. B. The inner part of the cerebral hemisphere looks grey because its fibre tracts are covered by myelin sheath. C. The cerebrum wraps around the thalamus, a major coordinating centre for sensory and motor signalling. D. The cerebral aqueduct passes through the medulla oblongata. Which of these are correct?
1. AA, B and C only
2. BC and D only
3. CA, C and D only
4. DA and C only
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Question 13 · Medium
Arrange in the correct order the events at one site of a resting axon after a stimulus is applied there. A. Permeability to Na⁺ falls and K⁺ diffuses outside B. The membrane becomes freely permeable to Na⁺ C. The resting potential is restored and the fibre is ready for the next stimulus D. Rapid influx of Na⁺ makes the inner surface positive
1. AB, D, A, C
2. BA, B, D, C
3. CD, B, A, C
4. DB, A, D, C
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Question 14 · Medium
Given below are two statements: Statement I: The midbrain lies between the pons and the medulla oblongata. Statement II: The hypothalamus contains neurosecretory cells that secrete hormones called hypothalamic hormones. Choose the correct answer.
1. ABoth Statement I and Statement II are correct
2. BStatement I is correct but Statement II is incorrect
3. CStatement I is incorrect but Statement II is correct
4. DBoth Statement I and Statement II are incorrect
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Question 15 · Easy
In each cycle, the sodium-potassium pump of a resting axon
1. Amoves 3 Na⁺ out and 2 K⁺ into the cell
2. Bmoves 2 Na⁺ out and 3 K⁺ into the cell
3. Cmoves equal numbers of Na⁺ and K⁺ in the same direction
4. Dmoves 3 K⁺ out and 2 Na⁺ into the cell
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Question 16 · Medium
Look at these statements about a neuron: A. Dendrites transmit impulses away from the cell body. B. Nissl's granules are present in the cell body and in the dendrites. C. Axon branches end in synaptic knobs that have synaptic vesicles containing neurotransmitters. D. Unipolar neurons are usually found in the embryonic stage. Which of these are correct?
1. AB and C only
2. BA, B and C only
3. CA, C and D only
4. DB, C and D only
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Question 17 · Medium
Match List-I with List-II. List-I (Part of brain) A. Thalamus B. Corpora quadrigemina C. Limbic system D. Association areas List-II (Feature or function) I. Four round swellings on the dorsal side of the midbrain II. Intersensory associations, memory and communication III. Major coordinating centre for sensory and motor signalling IV. With the hypothalamus, regulates sexual behaviour and emotional reactions Choose the correct answer.
1. AA-III, B-I, C-IV, D-II
2. BA-III, B-II, C-IV, D-I
3. CA-II, B-I, C-IV, D-III
4. DA-IV, B-I, C-III, D-II
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Question 18 · Hard
Given below are two statements: Statement I: In a resting axon, the axoplasm has a high concentration of K⁺ and negatively charged proteins and a low concentration of Na⁺, while the outside fluid has a high Na⁺ and low K⁺ concentration. Statement II: After the action potential at a site, the resting potential is restored by a rapid influx of K⁺ into the axon. Choose the correct answer.
1. AStatement I is incorrect but Statement II is correct
2. BStatement I is correct but Statement II is incorrect
3. CBoth Statement I and Statement II are incorrect
4. DBoth Statement I and Statement II are correct
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Question 19 · Easy
In a myelinated nerve fibre, the gaps between two adjacent myelin sheaths are called
1. Anodes of Ranvier
2. BNissl's granules
3. Csynaptic knobs
4. Dsynaptic clefts
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Question 20 · Medium
Given below are two statements: Statement I: Myelinated nerve fibres are found in spinal and cranial nerves. Statement II: An unmyelinated nerve fibre is enclosed by a Schwann cell that does not form a myelin sheath, and such fibres are common in the autonomous and somatic neural systems. Choose the correct option.
1. ABoth Statement I and Statement II are incorrect
2. BStatement I is incorrect but Statement II is correct
3. CBoth Statement I and Statement II are correct
4. DStatement I is correct but Statement II is incorrect
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Question 21 · Easy
Neurons with one axon and one dendrite are called bipolar neurons. Where does NCERT state that such neurons are found?
1. ACerebral cortex
2. BRetina of the eye
3. CSpinal cord
4. DCerebellar cortex
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Question 22 · Medium
Assertion A: Electrical synapses are rare in our system. Reason R: At an electrical synapse, the pre- and post-synaptic membranes are separated by a fluid-filled synaptic cleft. Choose the correct answer.
1. ABoth A and R are correct but R is not the correct explanation of A
2. BA is not correct but R is correct
3. CA is correct but R is not correct
4. DBoth A and R are correct and R is the correct explanation of A
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Neural Control and Coordination

Which part of the human brain contains the centres that control respiration, cardiovascular reflexes and gastric secretions?

A drug that blocks only neurotransmitter receptors on post-synaptic membranes is added to a preparation that has both electrical and chemical synapses. Which result is expected?

An electrode placed inside an axon shows that the inner surface turns positive at a stimulated site. Which event directly causes this reversal?

Arrange the following in order from the skull inward to the brain tissue. A. Arachnoid B. Cerebral cortex C. Pia mater D. Dura mater Choose the correct order.

Given below are two statements: Statement I: At rest, the axonal membrane is more permeable to K⁺ than to Na⁺. Statement II: The sodium-potassium pump moves 3 Na⁺ into the axon for every 2 K⁺ it moves out. Choose the correct answer.

Given below are two statements: Statement I: An unmyelinated nerve fibre is enclosed by a Schwann cell that does not form a myelin sheath around the axon. Statement II: The gaps between two adjacent myelin sheaths on an axon are called synaptic clefts. Choose the correct answer.

A stimulus makes site A of a resting axon depolarised, while site B just ahead of it is still polarised. In which directions does local current flow between the two sites?

The two cerebral hemispheres of the human brain are connected by a tract of nerve fibres called the

Given below are two statements: Statement I: The midbrain lies between the pons and the medulla oblongata. Statement II: The hypothalamus contains neurosecretory cells that secrete hormones called hypothalamic hormones. Choose the correct answer.

In each cycle, the sodium-potassium pump of a resting axon

In a myelinated nerve fibre, the gaps between two adjacent myelin sheaths are called

Neurons with one axon and one dendrite are called bipolar neurons. Where does NCERT state that such neurons are found?

Assertion A: Electrical synapses are rare in our system. Reason R: At an electrical synapse, the pre- and post-synaptic membranes are separated by a fluid-filled synaptic cleft. Choose the correct answer.