Nervous System

50. Which statement about nervous tissue is incorrect?

[RRB Group D (9 Aug 2026, Shift 1; 2025 recruitment cycle)]

• (A) Nerve impulses travel along nerve fibres.
• (B) The spinal cord contains nervous tissue.
• (C) An axon is a long extension of a neuron.
• (D) The cells responsible for nerve impulses are called nephrons.

Answer: (D) The cells responsible for nerve impulses are called nephrons.

Explanation: Neurons, not nephrons, are the excitable signalling cells of nervous tissue. Nephrons are microscopic functional units of the kidneys. A neuron possesses a cell body and processes, including an axon, that help transmit information through the nervous system.

49. The brain and spinal cord are composed primarily of which tissue?

[SSC GD Constable (19 May 2026, Shift 3)]

• (A) Muscular tissue
• (B) Connective tissue
• (C) Nervous tissue
• (D) Epithelial tissue

Answer: (C) Nervous tissue

Explanation: The brain and spinal cord constitute the central nervous system and contain neurons supported by neuroglial cells. Nervous tissue detects, processes and conducts signals. Connective, muscular and epithelial tissues perform important functions but are not the primary functional tissue of these organs.

48. Which neurotransmitter do sympathetic preganglionic neurons release at autonomic ganglia?

[UPHESC Assistant Professor, Zoology (18 Apr 2026)]

• (A) Acetylcholine
• (B) Noradrenaline
• (C) Dopamine
• (D) Adrenaline

Answer: (A) Acetylcholine

Explanation: Preganglionic fibres of both sympathetic and parasympathetic divisions release acetylcholine onto nicotinic receptors in autonomic ganglia. Most sympathetic postganglionic fibres instead release noradrenaline at their target organs. Distinguishing the two neuronal stages is essential for understanding autonomic signalling.

47. Which chemical messenger is released by motor neurons at the skeletal neuromuscular junction?

[DSSSB MTS (26 Apr 2026, Shift 3)]

• (A) Adrenaline
• (B) Serotonin
• (C) Dopamine
• (D) Acetylcholine

Answer: (D) Acetylcholine

Explanation: Acetylcholine is released when an impulse reaches a motor axon terminal. It binds to receptors on the muscle end plate, producing depolarisation and initiating contraction. Acetylcholinesterase rapidly breaks down the transmitter so that the muscle is not continuously stimulated.

46. Blood-pressure control, salivation and vomiting are chiefly associated with the medulla in which brain division?

[SSC MTS 2025 examination (4 Feb 2026, Shift 3)]

• (A) Medulla in the hindbrain
• (B) Cerebrum in the midbrain
• (C) Spinal cord in the forebrain
• (D) Medulla in the midbrain

Answer: (A) Medulla in the hindbrain

Explanation: The medulla oblongata forms the lowest portion of the brainstem and is classically grouped with the hindbrain. It contains vital autonomic and reflex centres involved in cardiovascular control, breathing, swallowing and vomiting, many of which function without conscious direction.

45. Which nerve category is correctly matched with its usual point of origin?

[RRB Group D (24 Dec 2025, Shift 1)]

• (A) Cranial nerves — brain
• (B) Cranial nerves — spinal cord
• (C) Spinal nerves — heart
• (D) Spinal nerves — brain

Answer: (A) Cranial nerves — brain

Explanation: Cranial nerves arise from the brain or brainstem, whereas spinal nerves arise from the spinal cord. Together they belong largely to the peripheral nervous system. The distinction helps explain how sensory and motor information travels between central nervous tissue and organs.

44. Which group of organs and structures is formed from nervous tissue?

[RRB Group D (22 Dec 2025, Shift 2)]

• (A) Kidneys, liver and spleen
• (B) Lungs, heart and stomach
• (C) Bones, tendons and ligaments
• (D) Brain, spinal cord and nerves

Answer: (D) Brain, spinal cord and nerves

Explanation: The brain and spinal cord are the main organs of the central nervous system, while peripheral nerves link them with the body. All contain specialised nervous tissue. Its neurons conduct messages, and supporting glial cells maintain a suitable working environment.

43. Which route best represents a simple spinal withdrawal reflex?

[RRB Group D (21 Dec 2025, Shift 2)]

• (A) Receptor → spinal cord → motor neuron → muscle
• (B) Receptor → brain → spinal cord → muscle
• (C) Receptor → spinal cord → brain → muscle
• (D) Receptor → motor neuron → spinal cord → muscle

Answer: (A) Receptor → spinal cord → motor neuron → muscle

Explanation: In a simplified reflex pathway, a receptor detects the stimulus and sensory input reaches the spinal cord, where it activates a motor route to the muscle. An interneuron commonly participates. The brain receives information too, but need not initiate the immediate withdrawal.

42. During a reflex arc, which neurons initially carry information from receptors towards the central nervous system?

[RRB Group D (19 Dec 2025, Shift 1)]

• (A) Motor neurons
• (B) Relay neurons
• (C) Sensory neurons
• (D) Effector muscle fibres

Answer: (C) Sensory neurons

Explanation: Sensory, or afferent, neurons carry signals from receptors toward the spinal cord or brain. Interneurons then often link sensory input to motor output. Motor neurons carry commands away from the central nervous system, while muscle fibres act as effectors.

41. What chiefly enables communication between the central nervous system and organs elsewhere in the body?

[RRB Group D (12 Dec 2025, Shift 1)]

• (A) Spinal cord only
• (B) Voluntary muscles
• (C) Peripheral nervous system
• (D) Involuntary muscles

Answer: (C) Peripheral nervous system

Explanation: The peripheral nervous system includes nerves and ganglia outside the brain and spinal cord. It carries incoming sensory messages and outgoing motor instructions. Its somatic and autonomic components together connect the central nervous system with skeletal muscles, glands and internal organs.

40. What is the usual direction of impulse transmission through the main parts of a neuron?

[SSC CHSL Tier I (30 Nov 2025, Shift 2)]

• (A) Dendrite → cell body → axon
• (B) Axon → dendrite → cell body
• (C) Cell body → dendrite → receptor
• (D) Synaptic cleft → muscle → dendrite

Answer: (A) Dendrite → cell body → axon

Explanation: Dendrites commonly receive synaptic input, the cell body integrates information, and an action potential travels along the axon toward its terminals. At chemical synapses, neurotransmitter release permits signalling onward. This arrangement explains functional polarity in a typical neuron.

39. Which brain structure ensures precise voluntary movements while maintaining posture and balance?

[SSC CHSL Tier I (27 Nov 2025, Shift 2)]

• (A) Cerebrum
• (B) Cerebellum
• (C) Medulla
• (D) Hypothalamus

Answer: (B) Cerebellum

Explanation: The cerebellum compares intended movements with sensory feedback and refines timing, force and coordination. Its activity supports gait, posture and equilibrium. It does not simply initiate conscious thought; those higher functions are associated more strongly with the cerebral cortex.

38. Consider these structures:
I. Heart;
II. Spinal cord.

Which belongs to the central nervous system?

[SSC CHSL Tier I (14 Nov 2025, Shift 3)]

• (A) Only I
• (B) Only II
• (C) Both I and II
• (D) Neither I nor II

Answer: (B) Only II

Explanation: The central nervous system comprises the brain and spinal cord. The spinal cord relays nerve impulses and processes many reflexes. The heart is a muscular organ of the circulatory system, although nerves of the autonomic system influence its rhythm.

37. Which brain region contains the main biological clock controlling circadian rhythms?

[SSC CGL Tier I (15 Sep 2025, Shift 3)]

• (A) Cerebellum
• (B) Hypothalamus
• (C) Medulla oblongata
• (D) Thalamus

Answer: (B) Hypothalamus

Explanation: The suprachiasmatic nucleus of the hypothalamus is the master circadian pacemaker. It receives light-related information through retinal pathways and helps synchronise sleep, hormones and other daily rhythms. The cerebellum is more concerned with coordination, while the medulla regulates essential autonomic functions.

36. Which is the correct conventional division of the human brain?

[UPSC CDS II, General Knowledge (14 Sep 2025)]

• (A) Forefront, standard and hindbrain
• (B) Forebrain, median and rear brain
• (C) Forebrain, midbrain and hindbrain
• (D) Precursor, mean and hindbrain

Answer: (C) Forebrain, midbrain and hindbrain

Explanation: For general biology, the human brain is grouped into forebrain, midbrain and hindbrain. The forebrain supports complex processing and homeostasis; the midbrain is involved in sensory and motor pathways; the hindbrain includes cerebellum, pons and medulla.

35. Which group of activities is most characteristically controlled by the hindbrain?

[UPSC NDA II, General Ability Test (14 Sep 2025)]

• (A) Involuntary responses such as salivation and vomiting
• (B) Conscious interpretation of every sensory impulse
• (C) Initiation of all deliberate thought
• (D) Awareness of hunger and satiety alone

Answer: (A) Involuntary responses such as salivation and vomiting

Explanation: The hindbrain contains the medulla, pons and cerebellum. Medullary centres control essential automatic reflexes such as vomiting and aspects of salivation and blood-pressure regulation. Balance is coordinated by the cerebellum, whereas hunger and satiety depend strongly on hypothalamic circuits.

34. Which amino acid is a biochemical precursor of the neurotransmitter serotonin?

[SSC CGL 2024 Tier II (20 Jan 2025)]

• (A) Tryptophan
• (B) Isoleucine
• (C) Valine
• (D) Methionine

Answer: (A) Tryptophan

Explanation: Serotonin, also called 5-hydroxytryptamine, is synthesised from the essential amino acid tryptophan. The pathway involves hydroxylation followed by decarboxylation. Serotonin participates in mood, appetite and sleep-related signalling, although those processes also depend on multiple other transmitters.

33. Cranial and spinal nerves together mainly form which nervous-system division?

[RRB Technician Grade III (28 Dec 2024, Shift 3)]

• (A) Peripheral nervous system
• (B) Central nervous system
• (C) Endocrine system
• (D) Digestive nervous system

Answer: (A) Peripheral nervous system

Explanation: Cranial and spinal nerves connect the brain and spinal cord to the remaining body, and thus belong to the peripheral nervous system. By contrast, the brain and spinal cord form the central nervous system, which integrates incoming information and coordinates responses.

32. Which of these is generally recognised as the longest type of cell in the human body?

[RRB ALP CBT I (27 Nov 2024, Shift 2)]

• (A) Nerve cell
• (B) Ovum
• (C) Red blood cell
• (D) Fat cell

Answer: (A) Nerve cell

Explanation: Some neurons possess axons extending from the spinal cord to distant muscles, potentially over a metre in an adult. That makes nerve cells notable for their length. The ovum is particularly large in diameter, but it is not the longest cell.

31. In which part of the nervous system are many common withdrawal-reflex arcs organised?

[RRB ALP CBT I (26 Nov 2024, Shift 3)]

• (A) Medulla
• (B) Forebrain
• (C) Spinal cord
• (D) Cerebellum

Answer: (C) Spinal cord

Explanation: The spinal cord contains local neural circuits that can coordinate rapid protective reflexes, such as pulling a hand away from heat. Sensory information enters through dorsal pathways and motor output exits through ventral pathways. The brain is informed but need not act first.

30. Epilepsy is primarily a disorder of which body structure?

[SSC MTS (7 Oct 2024, Shift 2)]

• (A) Brain cells and neural networks
• (B) Teeth and bones
• (C) Skin layers
• (D) Skeletal-muscle fibres alone

Answer: (A) Brain cells and neural networks

Explanation: Epilepsy is characterised by an enduring tendency to experience epileptic seizures arising from abnormal, excessive or synchronous neuronal activity in the brain. A seizure may cause changes in awareness, movement or sensation. It is a neurological rather than primarily muscular condition.

29. Match:
(a) cerebral cortex,
(b) hypothalamus,
(c) cerebellum,
(d) pons;

with
(1) temperature regulation,
(2) sensory perception,
(3) sleep–wake functions,
(4) posture and balance.

[TNPSC Group IV (2024)]

• (A) a-1, b-3, c-2, d-4
• (B) a-2, b-3, c-4, d-1
• (C) a-2, b-1, c-3, d-4
• (D) a-2, b-1, c-4, d-3

Answer: (D) a-2, b-1, c-4, d-3

Explanation: The cerebral cortex supports conscious sensory perception; the hypothalamus regulates temperature; the cerebellum coordinates posture and balance; and the pons contributes to sleep–wake regulation. Matching each structure with its dominant textbook role identifies the final sequence.

28. Which portion of the human brain plays the principal role in maintaining bodily balance?

[Kolkata Police SI Preliminary (28 Jan 2024)]

• (A) Cerebellum
• (B) Medulla oblongata
• (C) Thalamus
• (D) Midbrain

Answer: (A) Cerebellum

Explanation: The cerebellum combines vestibular, visual and proprioceptive input to adjust muscle activity and maintain equilibrium. It fine-tunes coordinated actions and posture. The thalamus is primarily a relay station; the medulla controls essential autonomic functions, and the midbrain serves other sensorimotor roles.

27. Which sequence correctly represents the pathway of a typical spinal reflex?

[UPSC CDS I, General Knowledge (16 Apr 2023)]

• (A) Receptor → sensory neuron → spinal relay neuron → motor neuron → effector
• (B) Receptor → sensory neuron → brain → relay neuron → motor neuron → effector
• (C) Receptor → motor neuron → spinal relay neuron → sensory neuron → effector
• (D) Receptor → motor neuron → brain → sensory neuron → effector

Answer: (A) Receptor → sensory neuron → spinal relay neuron → motor neuron → effector

Explanation: A receptor responds to a stimulus and passes information through a sensory neuron to spinal circuitry. A relay neuron commonly activates the appropriate motor neuron, which produces action in an effector muscle or gland. This local arrangement minimises response delay.

26. Which kind of cell is characteristically long and branched?

[SSC Selection Post, Matric Level (28 Jun 2023, Shift 1)]

• (A) Nerve cell
• (B) Columnar epithelial cell
• (C) White blood cell
• (D) Red blood cell

Answer: (A) Nerve cell

Explanation: A nerve cell has branched dendrites for receiving inputs and frequently a long axon for transmitting impulses. These structural specialisations support communication over considerable distances. Epithelial and blood cells have other shapes suited to covering surfaces or circulating through vessels.

25. The medulla oblongata belongs to which organ?

[MP Forest Guard / Jail Prahari (7 Jun 2023, Shift 1)]

• (A) Heart
• (B) Brain
• (C) Lungs
• (D) Stomach

Answer: (B) Brain

Explanation: The medulla oblongata is the lower segment of the brainstem, continuous with the spinal cord. It contains centres involved in respiration, cardiovascular regulation and protective reflexes. Although it influences functions of the heart and lungs, anatomically it belongs to the brain.

24. Which treatment principle improves neuromuscular signalling in myasthenia gravis?

[KVS PGT Biology (20 Feb 2023, Shift 1)]

• (A) Administration of adrenaline alone
• (B) Restriction of dietary protein
• (C) Use of an acetylcholinesterase inhibitor
• (D) Blocking all acetylcholine receptors

Answer: (C) Use of an acetylcholinesterase inhibitor

Explanation: Myasthenia gravis involves immune-mediated impairment of receptors at the skeletal neuromuscular junction. Acetylcholinesterase inhibitors reduce acetylcholine breakdown, increasing its availability at surviving receptors and improving muscle strength. Other immune-directed treatments may be needed depending on severity and clinical context.

23. Which nutrient helps prevent neural-tube defects involving a baby’s brain and spine?

[SSC MTS (12 Sep 2023, Shift 2)]

• (A) Vitamin E
• (B) Vitamin A
• (C) Vitamin C
• (D) Folic acid

Answer: (D) Folic acid

Explanation: Folic acid, the supplemental form of vitamin B9, is required during early development for proper neural-tube closure. Adequate intake around conception reduces the risk of serious defects such as spina bifida and anencephaly. The neural tube later forms central nervous structures.

22. Which ions are especially important in the electrical signalling of nerve cells?

[UPSC NDA II, General Ability Test (4 Sep 2022)]

• (A) Sodium alone
• (B) Potassium alone
• (C) Iron and calcium only
• (D) Sodium and potassium

Answer: (D) Sodium and potassium

Explanation: An action potential depends largely on sodium entering the neuron and potassium leaving it through voltage-gated channels. These movements change membrane voltage, allowing an impulse to propagate. The sodium–potassium ATPase maintains concentration gradients essential for repeated electrical signalling.

21. Which part of the ear converts sound-induced vibrations into electrical signals for the auditory pathway?

[UPSC NDA II, General Ability Test (4 Sep 2022)]

• (A) Auditory nerve alone
• (B) Cochlea
• (C) Eardrum alone
• (D) Eustachian tube

Answer: (B) Cochlea

Explanation: Specialised hair cells within the cochlea transform mechanical vibration into receptor signals and stimulate fibres of the auditory nerve. The eardrum conveys vibrations, while the Eustachian tube equalises pressure. The cochlea therefore performs the key sensory transduction step in hearing.

20. Which combination of tissues is directly responsible for generating and controlling most body movements?

[RRB Group D (26 Sep 2022, Shift 3)]

• (A) Nervous and connective tissues only
• (B) Nervous and epithelial tissues
• (C) Muscular and connective tissues only
• (D) Nervous and muscular tissues

Answer: (D) Nervous and muscular tissues

Explanation: Nervous tissue sends and processes commands, while muscular tissue contracts to produce movement. Motor neurons activate skeletal muscles at neuromuscular junctions. Connective tissue supports and transmits force, but neural control and muscular contraction are the two principal active components.

19. Which autonomic division generally conserves energy and restores resting bodily conditions?

[MPTET Varg 3 (17 Mar 2022, Shift 2)]

• (A) Sympathetic division
• (B) Parasympathetic division
• (C) Both divisions have identical actions
• (D) Neither autonomic division

Answer: (B) Parasympathetic division

Explanation: The parasympathetic division is associated with rest, digestion and energy conservation. It commonly slows the heart, promotes digestive activity and supports glandular secretion. The sympathetic division instead generally prepares the organism for activity or stress, although effects vary by organ.

18. A synapse is a junction through which a nerve impulse commonly passes from where to where?

[RRB NTPC CBT I (15 Feb 2021, Shift 1)]

• (A) One neuron to another
• (B) Brain directly to bone
• (C) One epithelial cell to another
• (D) One endocrine gland to another

Answer: (A) One neuron to another

Explanation: At a chemical synapse, neurotransmitter released by a presynaptic neuron crosses the synaptic cleft and binds receptors on a target cell. Synapses connect neural circuits and permit modulation of signalling. Some synapses are electrical and transfer ionic current more directly.

17. What is the basic structural and functional unit of the nervous system?

[SSC JE Civil Engineering (23 Mar 2021, Evening)]

• (A) Neuron
• (B) Cerebellum
• (C) Cerebrum
• (D) Nephron

Answer: (A) Neuron

Explanation: The neuron is an excitable cell specialised for receiving, integrating and transmitting information. Its cell body, dendrites and axon work together to support communication. The nephron is instead the basic functional unit of the kidney, while cerebrum and cerebellum are brain structures.

16. Assess the statements:
1. Humans have 31 pairs of spinal nerves.
2. Sympathetic and parasympathetic functions are complementary.

Which statement is incorrect?

[DSSSB TGT Natural Science (8 Sep 2021, Shift 1)]

• (A) Only 1
• (B) Both 1 and 2
• (C) Only 2
• (D) Neither 1 nor 2

Answer: (D) Neither 1 nor 2

Explanation: Both statements are valid in the textbook sense. The 31 spinal-nerve pairs connect the spinal cord to different body regions. Sympathetic and parasympathetic divisions often have opposing yet coordinated effects, enabling autonomic regulation and internal physiological balance.

15. Which effect is NOT a usual parasympathetic response?

[UP TGT Biology (2021)]

• (A) Slowing the heartbeat
• (B) Accelerating the heartbeat
• (C) Stimulating salivary secretion
• (D) Stimulating intestinal peristalsis

Answer: (B) Accelerating the heartbeat

Explanation: Parasympathetic activity commonly reduces heart rate through vagal signalling and favours digestion and glandular secretions. Acceleration of the heartbeat is more typical of sympathetic stimulation. The exact autonomic influence depends on the organ and its receptor types.

14. A neuron possessing several dendrites and one axon is termed which type?

[DSSSB PGT Biology (16 Jul 2021, Shift 1)]

• (A) Multipolar neuron
• (B) Bipolar neuron
• (C) Unipolar neuron
• (D) Anucleate neuron

Answer: (A) Multipolar neuron

Explanation: Multipolar neurons contain one axon and multiple dendritic processes emerging from the soma. They are common among motor neurons and interneurons in the central nervous system. Bipolar neurons instead have two main processes and are found in certain sensory pathways.

13. Which structure contains nerve fibres carrying messages to and from the brain and coordinating many reflex actions?

[RRB NTPC CBT I (30 Dec 2020, Shift 1)]

• (A) Spinal cord
• (B) Heart
• (C) Rib cage
• (D) Skeletal muscles

Answer: (A) Spinal cord

Explanation: The spinal cord is a central nervous-system pathway linking the brain to peripheral nerves. It includes ascending sensory and descending motor tracts, as well as circuits mediating reflexes. Muscles respond to commands but do not replace the spinal cord’s coordinating function.

12. How many pairs of cranial nerves are conventionally identified in humans?

[MPPSC State Service, General Studies (2020)]

• (A) 8 pairs
• (B) 12 pairs
• (C) 25 pairs
• (D) 31 pairs

Answer: (B) 12 pairs

Explanation: Humans conventionally have twelve pairs of cranial nerves, labelled I to XII. They carry sensory, motor or mixed fibres and are connected with structures of the head, neck and some internal organs. By comparison, spinal nerves number thirty-one pairs.

11. Consider:
1. The brain helps regulate heartbeat.
2. The brain helps maintain balance.

Which statements are correct?

[UPPSC Civil Services Preliminary, GS I (2020)]

• (A) 1 only
• (B) 2 only
• (C) Both 1 and 2
• (D) Neither 1 nor 2

Answer: (C) Both 1 and 2

Explanation: Medullary autonomic centres contribute to cardiovascular regulation, and the cerebellum plays a major part in balance and posture. Thus different brain regions perform both functions. The brain is not limited to conscious thought; it also directs many automatic physiological activities.

10. How many pairs of spinal nerves normally arise from the human spinal cord?

[WBCS Preliminary (2019)]

• (A) 12 pairs
• (B) 31 pairs
• (C) 31 single nerves
• (D) 12 single nerves

Answer: (B) 31 pairs

Explanation: The 31 pairs comprise eight cervical, twelve thoracic, five lumbar, five sacral and one coccygeal pair. Spinal nerves are mixed nerves after their dorsal sensory and ventral motor roots join. They link the spinal cord with muscles, skin and viscera.

9. How many pairs of cranial nerves are present in a typical human?

[RPSC Senior Teacher Grade II, Science (18 Feb 2019)]

• (A) 6 pairs
• (B) 12 pairs
• (C) 24 pairs
• (D) 20 pairs

Answer: (B) 12 pairs

Explanation: There are twelve pairs of cranial nerves. Some are predominantly sensory, such as the optic nerve; others are motor or mixed. The vagus nerve is especially important for parasympathetic functions in the thoracic and abdominal organs.

8. The nicotinic acetylcholine receptor at a chemical synapse belongs to which class?

[CSIR-UGC NET Life Sciences (15 Dec 2019)]

• (A) Ligand-gated cation channel
• (B) Ligand-gated anion channel
• (C) Voltage-gated cation channel
• (D) Voltage-gated anion channel

Answer: (A) Ligand-gated cation channel

Explanation: The nicotinic acetylcholine receptor opens when acetylcholine binds, allowing mainly positive ions to cross its membrane pore. It is therefore a ligand-gated cation channel. At skeletal neuromuscular junctions, its activation produces end-plate depolarisation leading toward muscle excitation.

7. Which sets contain correctly identified neurotransmitters:
(a) acetylcholine and GABA,
(b) dopamine and noradrenaline,
(c) lysine and histamine,
(d) pyruvate and acetyl-CoA?

[MPSC Subordinate Services Preliminary (2019)]

• (A) (a) only
• (B) (c) only
• (C) (a) and (b)
• (D) (c) and (d)

Answer: (C) (a) and (b)

Explanation: Acetylcholine, GABA, dopamine and noradrenaline are established neurotransmitters. Lysine is chiefly an amino acid rather than a classical transmitter, so its pairing with histamine is unsuitable here. Pyruvate and acetyl-CoA are metabolic intermediates, not standard synaptic neurotransmitter pairs.

6. Which of the following represents the correct simplified circuit of a reflex arc?

[UPSC NDA, General Ability Test (9 Sep 2018)]

• (A) Effector → sensory neuron → spinal cord → motor neuron → receptor
• (B) Receptor → sensory neuron → spinal cord → motor neuron → effector
• (C) Receptor → sensory neuron → brain → motor neuron → effector
• (D) Sensory neuron → receptor → brain → effector → motor neuron

Answer: (B) Receptor → sensory neuron → spinal cord → motor neuron → effector

Explanation: The receptor detects a stimulus, the sensory neuron conveys it to spinal circuitry, and a motor neuron activates an effector. Although additional interneurons are frequent, this simplified order is correct. Such circuits permit a rapid involuntary response before conscious evaluation.

5. Which organ’s functional tissue lacks pain receptors and would not itself feel a needle prick?

[UPPSC Civil Services Preliminary (2017)]

• (A) Skin
• (B) Brain
• (C) Heart
• (D) Eye

Answer: (B) Brain

Explanation: Brain parenchyma itself lacks pain-sensitive nociceptors, even though the brain processes pain information arriving from elsewhere. The scalp, meninges and some blood vessels are pain-sensitive, which explains how headaches can occur despite the insensitivity of brain tissue.

4. Which functions can the human brain perform: thinking, regulation of heartbeat, and maintenance of body balance?

[UPPSC Civil Services Preliminary, GS I (2016)]

• (A) Thinking only
• (B) Heartbeat regulation only
• (C) Balance only
• (D) All three functions

Answer: (D) All three functions

Explanation: Higher cerebral regions support thinking, brainstem centres influence cardiovascular activity, and cerebellar pathways coordinate balance. These functions are distributed across different anatomical areas. Consequently the brain handles conscious cognition as well as involuntary physiological regulation and motor coordination.

3. During embryonic development, the retina arises as an outgrowth of which brain region?

[RPSC RAS Preliminary (2015 re-examination of 2013)]

• (A) Mesencephalon
• (B) Diencephalon
• (C) Telencephalon
• (D) Pons

Answer: (B) Diencephalon

Explanation: The neural retina develops from the optic vesicle, which grows out of the embryonic diencephalon. The optic nerve is likewise related developmentally to central nervous tissue. This is why the retina is considered a specialised neural structure rather than an ordinary peripheral receptor sheet.

2. Which part of the human brain is chiefly linked with memory and higher intellectual functions?

[CGPSC Preliminary, General Studies (2013)]

• (A) Medulla oblongata
• (B) Cerebrum
• (C) Brain cavity
• (D) Cerebellum

Answer: (B) Cerebrum

Explanation: The cerebrum, including the cerebral cortex and associated networks, is central to learning, memory, reasoning and conscious perception. The hippocampus is particularly important for forming many kinds of new memories. The cerebellum chiefly coordinates movement and also contributes to some cognitive processes.

1. Which region of the human brain acts as a major control centre for swallowing and vomiting?

[UPSC Civil Services Preliminary, General Studies (2007)]

• (A) Cerebellum
• (B) Cerebrum
• (C) Medulla oblongata
• (D) Pons

Answer: (C) Medulla oblongata

Explanation: The medulla oblongata houses brainstem circuits that coordinate swallowing, vomiting and other protective reflexes. It also contributes to vital breathing and cardiovascular regulation. The cerebellum chiefly refines motor coordination, whereas the cerebrum supports higher conscious functions.

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Prepared for competitive exam revision. The original wording and independently verified answer keys should be consulted for formal exam appeals.