Neural Control & Coordination – MCQs

Part 1 — Q1–Q25

Q1. The functional unit of the nervous system is the:

a) Glial cell
b) Neuron
c) Synapse
d) Nerve

Answer: b) Neuron

a) Glial cell — supports neurons (nutrition, myelination, immune), but not the primary signaling unit.
b) Neuron — correct; specialized cell for transmitting electrical signals.
c) Synapse — junction between neurons; important but not the cellular unit.
d) Nerve — bundle of axons (many neurons) — tissue level, not the basic unit.

Q2. Which part of neuron receives incoming signals?

a) Axon hillock
b) Axon terminal
c) Dendrite
d) Myelin sheath

Answer: c) Dendrite

a) Axon hillock — integrates inputs and often initiates action potentials.
b) Axon terminal — releases neurotransmitter to next cell.
c) Dendrite — correct; primary receptive region that receives synaptic inputs.
d) Myelin sheath — insulating layer; not a receptive structure.

Q3. The gap between two adjacent myelin sheath segments is called:

a) Node of Ranvier
b) Synaptic cleft
c) Axon hillock
d) Dendritic spine

Answer: a) Node of Ranvier

a) Node of Ranvier — correct; unmyelinated gap where action potentials are regenerated.
b) Synaptic cleft — gap between pre- and postsynaptic membranes.
c) Axon hillock — trigger zone at beginning of axon.
d) Dendritic spine — small protrusion on dendrite where synapses form.

Q4. Saltatory conduction refers to:

a) Passive spread of current in dendrites
b) Action potential jumping between Nodes of Ranvier along myelinated axon
c) Continuous conduction along unmyelinated axon
d) Transmission across a chemical synapse

Answer: b) Action potential jumping between Nodes of Ranvier

a) Passive spread — graded potentials, not saltatory conduction.
b) Saltatory conduction — correct; myelination causes APs to “jump,” increasing conduction velocity.
c) Continuous conduction — occurs in unmyelinated fibers (slower).
d) Chemical synapse transmission — different process.

Q5. Which ion influx causes the rising phase (depolarization) of a neuronal action potential?

a) K⁺ influx
b) Cl⁻ influx
c) Na⁺ influx
d) Ca²⁺ efflux

Answer: c) Na⁺ influx

a) K⁺ efflux (not influx) causes repolarization.
b) Cl⁻ influx hyperpolarizes neurons (inhibitory).
c) Na⁺ influx — correct; opening of voltage-gated Na⁺ channels depolarizes membrane.
d) Ca²⁺ efflux not primary cause of AP upstroke in most neurons.

Q6. The refractory period of a neuron ensures:

a) Action potentials can travel backward easily
b) Overlapping action potentials sum linearly
c) Unidirectional propagation of action potentials and limits firing frequency
d) Immediate re-excitation of the same patch of membrane

Answer: c) Unidirectional propagation and limits firing frequency

a) Refractory period prevents backward propagation, so (a) is false.
b) Refractory period prevents simple summation of APs at same site.
c) Correct; absolute/relative refractory periods ensure APs move forward and set max firing rate.
d) Immediate re-excitation is prevented during absolute refractory period.

Q7. Which glial cell produces myelin in the peripheral nervous system (PNS)?

a) Oligodendrocytes
b) Astrocytes
c) Schwann cells
d) Microglia

Answer: c) Schwann cells

a) Oligodendrocytes — produce myelin in the CNS, not PNS.
b) Astrocytes — support, blood–brain barrier, metabolic roles.
c) Schwann cells — correct; each Schwann cell myelinates one PNS axon segment.
d) Microglia — immune cells of CNS.

Q8. Chemical synapses transmit signals primarily by:

a) Gap junctions allowing direct ionic flow
b) Release of neurotransmitter from presynaptic terminal and receptor activation postsynaptically
c) Electrical field effects only
d) Passive current spread through extracellular fluid

Answer: b) Release of neurotransmitter

a) Gap junctions describe electrical synapses (direct channels), not chemical synapses.
b) Correct; neurotransmitter release and binding mediate chemical synaptic transmission.
c) Field effects are minor; primary mechanism is chemical.
d) Passive spread alone cannot account for synaptic specificity.

Q9. Which neurotransmitter is the principal excitatory transmitter in the mammalian CNS?

a) GABA
b) Glycine
c) Glutamate
d) Serotonin

Answer: c) Glutamate

a) GABA — main inhibitory neurotransmitter in brain.
b) Glycine — inhibitory in spinal cord and brainstem.
c) Glutamate — correct; major excitatory neurotransmitter mediating fast synaptic transmission.
d) Serotonin — modulatory, involved in mood, not the primary fast excitatory transmitter.

Q10. The principal inhibitory neurotransmitter in the brain is:

a) Glutamate
b) GABA
c) Acetylcholine
d) Dopamine

Answer: b) GABA

a) Glutamate — excitatory.
b) GABA — correct; activation of GABA_A receptors causes Cl⁻ influx → hyperpolarization.
c) Acetylcholine — excitatory at NMJ and some CNS pathways; modulatory elsewhere.
d) Dopamine — modulatory, not the chief inhibitory transmitter.

Q11. Which area of the brain is primarily responsible for higher cognitive functions (thinking, planning, voluntary movement)?

a) Cerebellum
b) Medulla oblongata
c) Cerebral cortex (cerebrum)
d) Thalamus

Answer: c) Cerebral cortex (cerebrum)

a) Cerebellum — coordination, balance, fine tuning of movement.
b) Medulla — autonomic control (breathing, heart rate).
c) Cerebral cortex — correct; site of higher cognition, motor planning, sensory perception.
d) Thalamus — relay station for sensory information to cortex.

Q12. Broca’s area lesion typically causes:

a) Loss of comprehension of language (receptive aphasia)
b) Problems in speech production (expressive aphasia)
c) Visual field defects
d) Memory loss only

Answer: b) Problems in speech production (expressive aphasia)

a) Receptive aphasia is associated with Wernicke’s area lesion.
b) Broca’s area — correct; lesion causes non-fluent, effortful speech with preserved comprehension.
c/d) Not primary symptoms of Broca’s lesion.

Q13. Which structure connects the left and right cerebral hemispheres?

a) Fornix
b) Corpus callosum
c) Internal capsule
d) Optic chiasm

Answer: b) Corpus callosum

a) Fornix — part of limbic system (hippocampal connections).
b) Corpus callosum — correct; major commissural fiber bundle connecting hemispheres.
c) Internal capsule — projection fibers between cortex and brainstem.
d) Optic chiasm — crossing of optic nerve fibers.

Q14. The blood–brain barrier (BBB) is formed mainly by:

a) Endothelial cells with tight junctions and astrocyte end-feet
b) Schwann cells
c) Leaky sinusoidal capillaries
d) Microglia only

Answer: a) Endothelial cells with tight junctions and astrocyte end-feet

a) Correct; BBB formed by tight endothelial junctions, pericytes, and astrocytic end-feet.
b) Schwann cells — PNS myelination.
c) Sinusoidal capillaries are in liver, not brain.
d) Microglia are immune cells, not primary BBB-forming elements.

Q15. Long-term potentiation (LTP), a cellular model of learning and memory, is most strongly associated with changes at synapses involving which receptor?

a) GABA_A receptor
b) AMPA and NMDA glutamate receptors (especially NMDA)
c) Nicotinic ACh receptor
d) Glycine receptor

Answer: b) AMPA and NMDA (especially NMDA)

a) GABA_A — inhibitory, less implicated in LTP induction.
b) Correct; NMDA receptor activation allows Ca²⁺ influx triggering signaling cascades that strengthen synapses (LTP). AMPA receptors are upregulated.
c/d) Not central to hippocampal LTP.

Q16. The autonomic nervous system divisions that generally produce “rest-and-digest” responses are:

a) Sympathetic nervous system
b) Parasympathetic nervous system
c) Somatic nervous system
d) Enteric nervous system only

Answer: b) Parasympathetic nervous system

a) Sympathetic — “fight-or-flight” responses.
b) Parasympathetic — correct; promotes digestion, decreased heart rate, energy conservation.
c) Somatic — voluntary motor control.
d) Enteric — operates gut locally but parasympathetic modulates it.

Q17. Preganglionic neurons of the sympathetic nervous system predominantly exit the spinal cord from which region?

a) Cervical region only
b) Thoracolumbar (T1–L2) region
c) Sacral region only
d) Whole spinal cord uniformly

Answer: b) Thoracolumbar (T1–L2) region

a/c/d) Incorrect distributions.
b) Correct; sympathetic preganglionic cell bodies are in thoracolumbar intermediolateral columns.

Q18. The major parasympathetic outflow to thoracic and abdominal viscera is carried by which cranial nerve?

a) Glossopharyngeal (IX)
b) Trigeminal (V)
c) Vagus (X)
d) Hypoglossal (XII)

Answer: c) Vagus (X)

a) Glossopharyngeal supplies some head structures and carotid body innervation.
b) Trigeminal — facial sensation and mastication; not major parasympathetic efferent to viscera.
c) Vagus — correct; supplies majority of parasympathetic innervation to thoracic/abdominal organs.
d) Hypoglossal — motor to tongue.

Q19. Sympathetic postganglionic neurons predominantly release which neurotransmitter at target organs?

a) Acetylcholine
b) Norepinephrine (noradrenaline)
c) Dopamine
d) Serotonin

Answer: b) Norepinephrine (noradrenaline)

a) ACh is released by preganglionic neurons (both sympathetic & parasympathetic) and by sympathetic innervation of sweat glands as exception.
b) Correct; most sympathetic postganglionic fibers release norepinephrine.
c/d) Not typical primary sympathetic transmitters.

Q20. Which receptor type mediates fast excitatory transmission at the neuromuscular junction?

a) Muscarinic ACh receptor
b) Nicotinic ACh receptor (ionotropic)
c) GABA_B receptor
d) Adrenergic β receptor

Answer: b) Nicotinic ACh receptor

a) Muscarinic — metabotropic ACh receptors in autonomic targets, slower.
b) Nicotinic — correct; ionotropic receptor on muscle endplate causing rapid depolarization.
c/d) Not involved in NMJ fast excitation.

Q21. A lesion of the dorsal root of a spinal nerve would primarily cause:

a) Loss of motor function (paralysis) in that dermatome/myotome
b) Loss of sensory modalities from that dermatome (sensory loss)
c) Autonomic hyperactivity only
d) Increased reflexes exclusively

Answer: b) Loss of sensory modalities

a) Motor fibers travel in ventral (ventrolateral) roots; dorsal root lesion spares motor output.
b) Correct; dorsal root contains sensory afferents from peripheral receptors.
c/d) Not primary consequences.

Q22. The stretch (myotatic) reflex (e.g., knee jerk) is mediated by which receptor?

a) Golgi tendon organ
b) Muscle spindle (intrafusal fibers)
c) Nociceptor
d) Pacinian corpuscle

Answer: b) Muscle spindle

a) Golgi tendon organ senses tension and mediates inverse reflex (protective inhibition).
b) Muscle spindle — correct; Ia afferents signal stretch → monosynaptic excitation of alpha motor neurons.
c/d) Not primary for stretch reflex.

Q23. Which brain region is primarily responsible for coordination and timing of voluntary movements?

a) Basal ganglia
b) Cerebellum
c) Hippocampus
d) Hypothalamus

Answer: b) Cerebellum

a) Basal ganglia important for initiation and scaling of movements and movement selection.
b) Cerebellum — correct; coordinates timing, precision, and motor learning.
c/d) Not the chief coordinators of movement.

Q24. Parkinson’s disease is primarily caused by degeneration of dopaminergic neurons in which area?

a) Substantia nigra pars compacta (part of basal ganglia)
b) Cerebellar cortex
c) Motor cortex
d) Hippocampus

Answer: a) Substantia nigra pars compacta

a) Correct; dopamine loss in substantia nigra disrupts basal ganglia circuits → bradykinesia, rigidity, tremor.
b–d) Not primary sites for Parkinson’s pathology.

Q25. Which nerve mediates the pupillary light reflex efferent limb (constriction via parasympathetic)?

a) Oculomotor nerve (III)
b) Trochlear nerve (IV)
c) Abducens nerve (VI)
d) Optic nerve (II)

Answer: a) Oculomotor nerve (III)

a) Oculomotor nerve — correct; parasympathetic fibers to sphincter pupillae cause constriction.
b/c) Trochlear/abducens — control specific extraocular muscles.
d) Optic nerve carries afferent (sensory) limb of reflex, not efferent.

Part 2: Neural Control and Coordination (Q26–Q50)

Q26. Which part of the brain controls respiration, heartbeat, and swallowing?

a) Cerebellum
b) Medulla oblongata ✅
c) Cerebrum
d) Hypothalamus

Explanation:
The medulla oblongata regulates vital involuntary functions such as heartbeat, respiration, and swallowing.

Q27. The nodes of Ranvier are found in:

a) Non-myelinated neurons
b) Myelinated neurons ✅
c) Both myelinated and non-myelinated neurons
d) None of the above

Explanation:
Nodes of Ranvier are gaps between myelin sheaths in myelinated axons that help in saltatory conduction.

Q28. Which ion influx is primarily responsible for depolarization of neurons?

a) Potassium
b) Sodium ✅
c) Calcium
d) Chloride

Explanation:
During depolarization, Na⁺ ions enter the neuron rapidly, making the inside more positive.

Q29. Which part of the human brain controls balance and posture?

a) Cerebrum
b) Medulla
c) Cerebellum ✅
d) Hypothalamus

Explanation:
The cerebellum is responsible for maintaining equilibrium, posture, and coordination of voluntary movements.

Q30. Which neurotransmitter is involved in neuromuscular junctions?

a) Dopamine
b) Acetylcholine ✅
c) Serotonin
d) Noradrenaline

Explanation:
Acetylcholine (ACh) is released at the neuromuscular junction, initiating muscle contraction.

Q31. The sympathetic nervous system mainly prepares the body for:

a) Sleep
b) Rest
c) Fight or flight ✅
d) Digestion

Explanation:
The sympathetic nervous system activates responses like increased heart rate and pupil dilation for fight-or-flight situations.

Q32. The nerve that connects the eye to the brain is:

a) Auditory nerve
b) Optic nerve ✅
c) Olfactory nerve
d) Vagus nerve

Explanation:
The optic nerve transmits visual information from the retina to the brain.

Q33. Which of the following is a mixed nerve?

a) Sensory nerve only
b) Motor nerve only
c) Spinal nerve ✅
d) Olfactory nerve

Explanation:
Spinal nerves carry both sensory (afferent) and motor (efferent) fibers, hence called mixed nerves.

Q34. The junction between two neurons is called:

a) Synapse ✅
b) Node of Ranvier
c) Dendrite
d) Axon hillock

Explanation:
A synapse is the functional junction between two neurons where neurotransmitters are released.

Q35. Which ion is required for the release of neurotransmitters at the synapse?

a) Sodium
b) Potassium
c) Calcium ✅
d) Chloride

Explanation:
Calcium ions (Ca²⁺) enter the synaptic terminal, triggering neurotransmitter release.

Q36. Which lobe of the cerebrum is associated with vision?

a) Frontal lobe
b) Temporal lobe
c) Occipital lobe ✅
d) Parietal lobe

Explanation:
The occipital lobe processes visual information.

Q37. The outermost covering of the brain is:

a) Pia mater
b) Arachnoid mater
c) Dura mater ✅
d) Myelin sheath

Explanation:
The dura mater is the tough, outermost covering of the brain and spinal cord.

Q38. The refractory period in a neuron ensures:

a) Faster conduction
b) Backward conduction prevention ✅
c) Stronger action potential
d) Weaker action potential

Explanation:
The refractory period prevents an action potential from moving backward, ensuring unidirectional conduction.

Q39. Which receptor is responsible for detecting smell?

a) Photoreceptors
b) Chemoreceptors ✅
c) Thermoreceptors
d) Mechanoreceptors

Explanation:
Chemoreceptors in the nasal cavity detect different odor molecules.

Q40. Which cranial nerve controls hearing and balance?

a) Olfactory nerve
b) Auditory nerve (Vestibulocochlear) ✅
c) Optic nerve
d) Trochlear nerve

Explanation:
The vestibulocochlear (auditory) nerve transmits signals for hearing and balance.

Q41. Saltatory conduction occurs in:

a) Non-myelinated axons
b) Myelinated axons ✅
c) Both types of axons
d) None of the above

Explanation:
In myelinated axons, impulses jump from one node of Ranvier to the next, called saltatory conduction.

Q42. Which part of the brain regulates hunger and thirst?

a) Cerebellum
b) Hypothalamus ✅
c) Cerebrum
d) Pons

Explanation:
The hypothalamus regulates hunger, thirst, temperature, and endocrine functions.

Q43. Which of the following is NOT a function of cerebrospinal fluid (CSF)?

a) Cushioning the brain
b) Transporting nutrients
c) Conducting nerve impulses ✅
d) Removing metabolic waste

Explanation:
CSF protects and nourishes the brain but does not conduct impulses.

Q44. The nerve impulse transmission across synapse is:

a) Electrical
b) Chemical ✅
c) Both electrical and chemical
d) Mechanical

Explanation:
Impulse transmission across a synapse is chemical, mediated by neurotransmitters.

Q45. The structural and functional unit of the nervous system is:

a) Axon
b) Neuron ✅
c) Synapse
d) Glial cell

Explanation:
The neuron is the basic structural and functional unit of the nervous system.

Q46. Parkinson’s disease is caused due to deficiency of:

a) Acetylcholine
b) Dopamine ✅
c) Serotonin
d) GABA

Explanation:
Dopamine deficiency in the brain’s substantia nigra leads to Parkinson’s disease.

Q47. The inner ear structure responsible for hearing is:

a) Semicircular canals
b) Cochlea ✅
c) Pinna
d) Tympanum

Explanation:
The cochlea contains the organ of Corti, which detects sound vibrations.

Q48. Which ion exits during repolarization of the neuron?

a) Sodium
b) Potassium ✅
c) Calcium
d) Chloride

Explanation:
During repolarization, K⁺ ions exit the neuron, restoring negative charge inside.

Q49. Which cranial nerve is the longest and extends to thoracic and abdominal organs?

a) Optic nerve
b) Vagus nerve ✅
c) Facial nerve
d) Olfactory nerve

Explanation:
The vagus nerve (cranial nerve X) regulates thoracic and abdominal organ functions.

Q50. The light-sensitive pigment in rods of the retina is:

a) Iodopsin
b) Rhodopsin ✅
c) Melanin
d) Hemoglobin

Explanation:
Rhodopsin, present in rods, helps in dim-light vision (scotopic vision).

Part 3: Neural Control and Coordination (Q51–Q75)

Q51. The largest part of the human brain is:

a) Cerebellum
b) Medulla oblongata
c) Cerebrum ✅
d) Pons

Answer: c) Cerebrum
Explanation: The cerebrum forms the largest portion of the brain and is responsible for higher mental functions like memory, reasoning, learning, and voluntary actions.

Q52. Which part of the brain is called the “balance center”?

a) Cerebrum
b) Medulla oblongata
c) Cerebellum ✅
d) Hypothalamus

Answer: c) Cerebellum
Explanation: The cerebellum controls balance, posture, and coordination of voluntary muscular activities.

Q53. The part of the brain that regulates breathing and heartbeat is:

a) Cerebellum
b) Medulla oblongata ✅
c) Pons
d) Thalamus

Answer: b) Medulla oblongata
Explanation: The medulla oblongata regulates involuntary functions such as respiration, heartbeat, and blood pressure.

Q54. Which part of the brain acts as a relay center for sensory impulses?

a) Hypothalamus
b) Thalamus ✅
c) Cerebellum
d) Midbrain

Answer: b) Thalamus
Explanation: The thalamus acts as a relay station for sensory information (except smell) before sending it to the cerebrum.

Q55. The part of the brain responsible for thermoregulation is:

a) Midbrain
b) Cerebellum
c) Hypothalamus ✅
d) Thalamus

Answer: c) Hypothalamus
Explanation: The hypothalamus regulates body temperature, hunger, thirst, sleep, and endocrine activities.

Q56. The meninges are:

a) Nerve fibers in CNS
b) Protective membranes of brain and spinal cord ✅
c) Neuroglial cells
d) Tracts of white matter

Answer: b) Protective membranes of brain and spinal cord
Explanation: Meninges are three protective layers (dura mater, arachnoid mater, pia mater) covering the brain and spinal cord.

Q57. The structural and functional unit of the nervous system is:

a) Neuron ✅
b) Neuroglia
c) Axon
d) Synapse

Answer: a) Neuron
Explanation: Neurons are specialized cells responsible for transmitting nerve impulses.

Q58. Which of the following is not a type of neuron?

a) Sensory neuron
b) Motor neuron
c) Interneuron
d) Myocyte ✅

Answer: d) Myocyte
Explanation: Myocytes are muscle cells, not nerve cells. The three main types of neurons are sensory, motor, and interneurons.

Q59. The junction between two neurons is called:

a) Synapse ✅
b) Axon terminal
c) Dendrite
d) Neurolemma

Answer: a) Synapse
Explanation: A synapse is the functional junction where one neuron communicates with another via neurotransmitters.

Q60. Neurotransmitters are released from:

a) Dendrites
b) Axon terminals ✅
c) Cell body
d) Nissl’s granules

Answer: b) Axon terminals
Explanation: Neurotransmitters are stored in synaptic vesicles and released into the synaptic cleft from axon terminals.

Q61. Which neurotransmitter is mainly excitatory in nature in the CNS?

a) Dopamine
b) Serotonin
c) Glutamate ✅
d) GABA

Answer: c) Glutamate
Explanation: Glutamate is the most abundant excitatory neurotransmitter in the CNS.

Q62. Which neurotransmitter is inhibitory in nature in the brain?

a) GABA ✅
b) Acetylcholine
c) Norepinephrine
d) Dopamine

Answer: a) GABA
Explanation: Gamma-aminobutyric acid (GABA) is the primary inhibitory neurotransmitter in the CNS.

Q63. Parkinson’s disease is due to the deficiency of:

a) Dopamine ✅
b) Acetylcholine
c) Serotonin
d) Glutamate

Answer: a) Dopamine
Explanation: Parkinson’s disease results from degeneration of dopaminergic neurons in the substantia nigra of the brain.

Q64. The myelin sheath around axons is produced by:

a) Astrocytes
b) Oligodendrocytes in CNS and Schwann cells in PNS ✅
c) Microglia
d) Ependymal cells

Answer: b) Oligodendrocytes in CNS and Schwann cells in PNS
Explanation: Myelin sheath is produced by Schwann cells in the peripheral nervous system and oligodendrocytes in the central nervous system.

Q65. Nodes of Ranvier are:

a) Gaps in myelin sheath ✅
b) Branches of dendrites
c) Types of interneurons
d) Synaptic vesicles

Answer: a) Gaps in myelin sheath
Explanation: Nodes of Ranvier are gaps in the myelin sheath that allow saltatory conduction of nerve impulses.

Q66. Saltatory conduction occurs in:

a) Non-myelinated axons
b) Myelinated axons ✅
c) Dendrites
d) Synaptic clefts

Answer: b) Myelinated axons
Explanation: In myelinated axons, impulses jump from one Node of Ranvier to another, speeding up conduction.

Q67. Which cranial nerve is the longest?

a) Optic nerve
b) Vagus nerve ✅
c) Trigeminal nerve
d) Facial nerve

Answer: b) Vagus nerve
Explanation: The vagus nerve (cranial nerve X) extends beyond the head and neck to thoracic and abdominal organs.

Q68. The total number of cranial nerves in humans is:

a) 10
b) 11
c) 12 ✅
d) 13

Answer: c) 12
Explanation: Humans have 12 pairs of cranial nerves emerging directly from the brain.

Q69. The total number of spinal nerves in humans is:

a) 21 pairs
b) 31 pairs ✅
c) 41 pairs
d) 51 pairs

Answer: b) 31 pairs
Explanation: Humans have 31 pairs of spinal nerves: 8 cervical, 12 thoracic, 5 lumbar, 5 sacral, and 1 coccygeal.

Q70. The outermost layer of the meninges is:

a) Pia mater
b) Arachnoid mater
c) Dura mater ✅
d) Endoneurium

Answer: c) Dura mater
Explanation: The dura mater is the tough, outermost protective layer of the brain and spinal cord.

Q71. The grey matter of the brain mainly consists of:

a) Axons
b) Myelinated fibers
c) Neuron cell bodies ✅
d) Neuroglia only

Answer: c) Neuron cell bodies
Explanation: Grey matter contains neuronal cell bodies, dendrites, and unmyelinated axons.

Q72. The white matter of the brain and spinal cord mainly consists of:

a) Neuron cell bodies
b) Myelinated axons ✅
c) Dendrites
d) Neuroglia

Answer: b) Myelinated axons
Explanation: White matter appears white due to myelin, which surrounds axons.

Q73. The reflex arc does not involve:

a) Receptor
b) Effector
c) Spinal cord
d) Cerebrum ✅

Answer: d) Cerebrum
Explanation: Reflex actions are rapid and involuntary, processed at the spinal cord level, not the cerebrum.

Q74. Which of the following is not part of the hindbrain?

a) Pons
b) Cerebellum
c) Medulla oblongata
d) Thalamus ✅

Answer: d) Thalamus
Explanation: Thalamus belongs to the forebrain, while pons, cerebellum, and medulla form the hindbrain.

Q75. The part of the eye responsible for regulating the amount of light entering it is:

a) Cornea
b) Iris ✅
c) Retina
d) Lens

Answer: b) Iris
Explanation: The iris adjusts the size of the pupil, regulating the amount of light entering the eye.

🧠 Human Physiology – Neural Control and Coordination

Part 4: MCQs (Q76–Q100)

Q76. Which part of the brain is primarily responsible for maintaining balance and posture?

a) Medulla oblongata
b) Cerebellum ✅
c) Hypothalamus
d) Cerebrum

Answer: b) Cerebellum

The cerebellum controls equilibrium, coordination of movement, and posture.
Medulla controls vital activities like heartbeat and respiration.
Hypothalamus regulates hunger, thirst, and temperature.
Cerebrum manages higher thought processes.

Q77. Which type of neurons carry impulses from the CNS to effectors?

a) Sensory neurons
b) Interneurons
c) Motor neurons ✅
d) Relay neurons

Answer: c) Motor neurons

Motor neurons transmit impulses from CNS → muscles/glands.
Sensory neurons carry signals from receptors → CNS.
Interneurons connect sensory and motor pathways.
Relay neurons is another name for interneurons.

Q78. Myelin sheath is formed by which cells in the peripheral nervous system?

a) Oligodendrocytes
b) Schwann cells ✅
c) Astrocytes
d) Microglia

Answer: b) Schwann cells

Schwann cells wrap around axons in the PNS forming myelin.
Oligodendrocytes form myelin in the CNS.
Astrocytes provide structural and metabolic support.
Microglia act as phagocytes in CNS.

Q79. Which cranial nerve is associated with smell sensation?

a) Optic nerve
b) Olfactory nerve ✅
c) Trigeminal nerve
d) Vagus nerve

Answer: b) Olfactory nerve

Olfactory nerve (cranial nerve I) → smell.
Optic nerve → vision.
Trigeminal → facial sensations.
Vagus → visceral control.

Q80. Which neurotransmitter is released at the neuromuscular junction?

a) Dopamine
b) Serotonin
c) Acetylcholine ✅
d) GABA

Answer: c) Acetylcholine

Acetylcholine (ACh) stimulates skeletal muscle contraction.
Dopamine regulates movement and reward pathways.
Serotonin affects mood.
GABA is inhibitory in CNS.

Q81. Saltatory conduction occurs in:

a) Non-myelinated axons
b) Myelinated axons ✅
c) Dendrites
d) Synaptic knobs

Answer: b) Myelinated axons

Saltatory conduction = impulse jumps between nodes of Ranvier.
Faster than conduction in non-myelinated axons.
Dendrites and synaptic knobs don’t conduct impulses in this way.

Q82. Which brain part controls hunger and thirst?

a) Pons
b) Hypothalamus ✅
c) Thalamus
d) Cerebellum

Answer: b) Hypothalamus

Hypothalamus regulates homeostasis (temperature, hunger, thirst, circadian rhythms).
Pons relays signals.
Thalamus relays sensory signals to cerebrum.
Cerebellum controls balance.

Q83. Refractory period of a neuron ensures that:

a) Impulse travels backward
b) Impulse travels unidirectionally ✅
c) Impulse stops completely
d) Neurons fire continuously

Answer: b) Impulse travels unidirectionally

Refractory period prevents backflow of nerve impulses, ensuring one-way conduction.

Q84. Which part of the ear converts sound waves into nerve impulses?

a) Tympanum
b) Ossicles
c) Cochlea ✅
d) Pinna

Answer: c) Cochlea

Cochlea contains organ of Corti with hair cells → convert sound into electrical signals.
Tympanum vibrates.
Ossicles amplify vibrations.
Pinna collects sound.

Q85. Which type of synapse transmits impulses faster?

a) Electrical synapse ✅
b) Chemical synapse
c) Both equally
d) None

Answer: a) Electrical synapse

Electrical synapses transmit impulses directly via gap junctions → very fast.
Chemical synapses use neurotransmitters → slower but flexible.

Q86. Which ion influx triggers neurotransmitter release?

a) Sodium (Na⁺)
b) Calcium (Ca²⁺) ✅
c) Potassium (K⁺)
d) Chloride (Cl⁻)

Answer: b) Calcium (Ca²⁺)

Ca²⁺ entry at presynaptic terminal triggers vesicle fusion and neurotransmitter release.
Na⁺, K⁺ are involved in action potential propagation, not release.

Q87. Which lobe of the cerebrum processes visual information?

a) Frontal lobe
b) Temporal lobe
c) Occipital lobe ✅
d) Parietal lobe

Answer: c) Occipital lobe

Occipital → vision.
Frontal → thinking, motor control.
Temporal → hearing, memory.
Parietal → sensory processing.

Q88. Which receptor detects body position and movement?

a) Thermoreceptors
b) Proprioceptors ✅
c) Photoreceptors
d) Chemoreceptors

Answer: b) Proprioceptors

Proprioceptors in muscles/joints sense body position and movement.
Thermoreceptors → temperature.
Photoreceptors → light.
Chemoreceptors → chemical stimuli.

Q89. Which of the following is NOT a function of cerebrospinal fluid (CSF)?

a) Shock absorption
b) Nutrient transport
c) Electrical impulse conduction ✅
d) Waste removal

Answer: c) Electrical impulse conduction

CSF protects brain/spinal cord, supplies nutrients, and removes wastes.
Neurons conduct impulses, not CSF.

Q90. Resting membrane potential of a neuron is approximately:

a) +70 mV
b) –70 mV ✅
c) +30 mV
d) 0 mV

Answer: b) –70 mV

Due to Na⁺/K⁺ pump and selective permeability.
Depolarization may reach +30 mV.
At rest, it is negative inside the cell.

Q91. Which part of the brain regulates the sleep-wake cycle?

a) Cerebrum
b) Cerebellum
c) Hypothalamus ✅
d) Medulla

Answer: c) Hypothalamus

Suprachiasmatic nucleus (SCN) in hypothalamus → circadian rhythm.
Cerebellum manages posture.
Medulla controls vital functions.

Q92. Which cranial nerve controls eye movement?

a) Olfactory
b) Oculomotor ✅
c) Optic
d) Auditory

Answer: b) Oculomotor

Oculomotor nerve (III) → eye muscles.
Optic → vision.
Olfactory → smell.
Auditory → hearing.

Q93. The reflex action of knee-jerk involves how many synapses?

a) One ✅
b) Two
c) Three
d) Many

Answer: a) One

Knee-jerk reflex is monosynaptic: sensory neuron → motor neuron directly.
Most reflexes are polysynaptic.

Q94. Which part of the eye regulates the amount of light entering?

a) Lens
b) Retina
c) Iris ✅
d) Cornea

Answer: c) Iris

Iris adjusts pupil size → regulates light.
Lens focuses light.
Retina detects light.
Cornea bends light.

Q95. Which brain structure acts as a relay station for sensory impulses?

a) Medulla
b) Thalamus ✅
c) Cerebellum
d) Hypothalamus

Answer: b) Thalamus

Thalamus relays sensory inputs (except smell) → cerebrum.
Hypothalamus regulates homeostasis.
Medulla controls vital centers.
Cerebellum controls coordination.

Q96. Which ion is mainly responsible for depolarization of neuron?

a) Sodium (Na⁺) ✅
b) Potassium (K⁺)
c) Calcium (Ca²⁺)
d) Chloride (Cl⁻)

Answer: a) Sodium (Na⁺)

Na⁺ influx during action potential causes depolarization.
K⁺ efflux causes repolarization.
Ca²⁺ triggers neurotransmitter release.

Q97. Which photoreceptor is responsible for color vision?

a) Rods
b) Cones ✅
c) Bipolar cells
d) Ganglion cells

Answer: b) Cones

Cones → color vision & high acuity.
Rods → dim light & night vision.
Bipolar/ganglion → relay signals.

Q98. Which division of the autonomic nervous system is known as “fight-or-flight”?

a) Parasympathetic
b) Sympathetic ✅
c) Somatic
d) Central

Answer: b) Sympathetic

Sympathetic → increases heart rate, dilates pupils, mobilizes energy.
Parasympathetic → rest-and-digest.
Somatic → voluntary control.
Central → brain & spinal cord.

Q99. Which disorder is due to dopamine deficiency in the brain?

a) Epilepsy
b) Alzheimer’s disease
c) Parkinson’s disease ✅
d) Schizophrenia

Answer: c) Parkinson’s disease

Dopamine deficiency in substantia nigra → Parkinson’s (tremors, rigidity).
Alzheimer’s → memory loss.
Epilepsy → seizures.
Schizophrenia → dopamine excess.

Q100. Which part of the nervous system connects the brain to the rest of the body?

a) Cerebrum
b) Spinal cord ✅
c) Cerebellum
d) Medulla

Answer: b) Spinal cord

Spinal cord transmits signals between brain and body.
Cerebrum manages higher functions.
Cerebellum coordinates balance.
Medulla controls autonomic functions.

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CBSE Class 11 Biology MCQs