The human nervous system is one of the most important topics in general science and biology for SSC, Railway (RRB NTPC, Group D), and UPSC aspirants. Examiners often ask about neurons, brain parts, nerves, reflex action, and common disorders, so a strong grip on these basics can fetch easy marks. Furthermore, this article gives you 20 original human nervous system MCQs with answers, clearly arranged in four simple sections. Each question comes with an Extra Information note that adds useful facts, so you learn more than the bare answer. Beginners can use the sets to build concepts, while experienced students can use them for quick revision and self-testing. Try each question before you check the answer, note your weak areas, and revisit those topics. In addition, keep reading to test your knowledge and practise offline with the PDF.
Neuron Structure and Nerve Impulse MCQs
Q1
Which cell is the structural and functional unit of the nervous system?
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Answer: B) Neuron
A neuron receives, processes, and sends electrical signals. Every neuron has a cell body, dendrites, and one axon. Moreover, mature neurons rarely divide, so repair after injury stays limited. In addition, the human brain contains about 86 billion neurons. Therefore, competitive exams often test the parts of a neuron.
Q2
Which part of a neuron receives signals from other neurons?
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Answer: D) Dendrite
Dendrites branch like the roots of a tree and pick up signals from nearby neurons. They carry the impulse toward the cell body. In contrast, the axon carries the impulse away from the cell body. Furthermore, a neuron usually has many dendrites but only one axon. As a result, students can remember the direction of signal flow easily.
Q3
Which cells form the myelin sheath around axons in the peripheral nervous system?
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Answer: A) Schwann cells
Schwann cells wrap around peripheral axons and form the myelin sheath. Also, oligodendrocytes do the same job in the brain and spinal cord. Myelin speeds up impulse travel because it insulates the axon. Consequently, damage to myelin slows nerve signals and causes weakness. For example, multiple sclerosis damages the myelin in the central nervous system.
Q4
What do we call the chemical messengers that cross a synapse to pass a signal from one neuron to the next?
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Answer: C) Neurotransmitters
Neurotransmitters leave the axon terminal and cross the tiny synaptic cleft. They then bind to receptors on the next cell. Similarly, the receiving cell may be another neuron, a muscle fibre, or a gland. Afterward, enzymes or reuptake pumps remove the chemical, so the signal stops. Thus, a chemical synapse allows signals to travel in only one direction.
Q5
What do we call the small gaps in the myelin sheath along an axon?
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Answer: B) Nodes of Ranvier
Nodes of Ranvier expose the axon membrane at regular intervals. Consequently, the impulse jumps from one node to the next. Scientists call this jumping saltatory conduction. As a result, myelinated fibres conduct impulses much faster than unmyelinated fibres. Moreover, this jumping saves energy for the neuron. The French anatomist Louis-Antoine Ranvier described these gaps.
Human Brain Parts and Functions MCQs
Q7
Which part of the brain mainly maintains body balance and coordinates muscle movement?
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Answer: A) Cerebellum
The cerebellum sits at the back of the skull, below the cerebrum. It fine-tunes movement and helps posture. For example, it lets a person walk in a straight line or catch a ball smoothly. However, it does not start voluntary movement; the cerebrum does that. Consequently, injury to the cerebellum causes shaky, uncoordinated movement.
Q8
Which part of the brain controls involuntary actions such as breathing and heartbeat?
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Answer: D) Medulla oblongata
The medulla oblongata joins the brain to the spinal cord. It also regulates blood pressure, swallowing, coughing, and vomiting. Because it controls life-support functions, serious damage to it can stop breathing. In addition, the medulla, pons, and midbrain together form the brainstem. Therefore, students should remember the medulla as a vital centre.
Q9
Which part of the brain regulates body temperature, hunger, and thirst?
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Answer: B) Hypothalamus
The hypothalamus is small, but it manages many vital functions. It keeps body temperature, hunger, thirst, and sleep cycles in balance. Moreover, it controls the pituitary gland, the master gland of the body. Therefore, the hypothalamus links the nervous system with the endocrine system. As a result, it appears often in exam questions on coordination.
Q10
How many protective membrane layers, called meninges, cover the brain and spinal cord?
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Answer: A) Three
The three layers are the dura mater, the arachnoid mater, and the pia mater. The dura mater forms the tough outer layer. Meanwhile, the pia mater hugs the brain surface. Cerebrospinal fluid circulates around the brain and cushions it. In addition, this fluid carries away waste. Meningitis, in contrast, is an infection or inflammation of these layers.
Spinal Cord, Nerves and Reflex Action MCQs
Q11
How many pairs of spinal nerves arise from the human spinal cord?
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Answer: D) 31
The 31 pairs include 8 cervical, 12 thoracic, 5 lumbar, 5 sacral, and 1 coccygeal pair. Each spinal nerve is mixed, so it carries both sensory and motor signals. For instance, one nerve can carry touch information to the cord and movement commands to a muscle. Also, spinal nerves leave the cord through gaps between the vertebrae. In contrast, twelve pairs of cranial nerves emerge from the brain.
Q12
Which is the longest cranial nerve, supplying the heart, lungs, and digestive organs?
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Answer: C) Vagus nerve
The vagus nerve, cranial nerve X, wanders from the brainstem down to the abdomen. It slows the heart rate and stimulates digestion. Hence, it forms a major part of the parasympathetic system. Moreover, the word vagus means wandering in Latin. In contrast, the optic nerve carries only visual signals.
Q13
Which part of the central nervous system mainly controls a simple reflex, such as pulling the hand away from a hot object?
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Answer: A) Spinal cord
In a reflex arc, the sensory neuron carries the signal to the spinal cord. There, an interneuron passes it straight to a motor neuron. As a result, the muscle reacts within a fraction of a second. Meanwhile, the brain receives the news a moment later. Therefore, a reflex action protects the body before the person thinks.
Q14
Which division of the autonomic nervous system prepares the body for a “fight or flight” response?
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Answer: B) Sympathetic
The sympathetic division speeds up the heartbeat and raises blood pressure during danger. It also widens the pupils and the airways. In contrast, the parasympathetic division slows the heart and restores calm. Thus, the two divisions work as opposing partners. For example, the sympathetic division helps a runner sprint, while the parasympathetic division helps the body digest food afterward.
Q15
Which is the largest nerve in the human body?
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Answer: D) Sciatic nerve
The sciatic nerve begins in the lower back and runs through the buttock and down the back of the thigh. It divides into the tibial and common fibular nerves near the knee. Therefore, it controls movement and sensation in most of the leg. For example, pressure on it causes sciatica, a shooting pain along the leg. Furthermore, spinal nerve roots L4 to S3 join to form it.
Neurotransmitters and Nervous System Disorders MCQs
Q16
A shortage of which neurotransmitter causes Parkinson’s disease?
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Answer: C) Dopamine
Parkinson’s disease develops when the dopamine-producing cells in the substantia nigra die. Dopamine helps smooth movement. Consequently, people with the disease develop tremors, stiff muscles, and slow movement. However, doctors can ease the symptoms with medicines such as levodopa. In addition, World Parkinson’s Day falls on 11 April.
Q17
Which disorder gradually destroys memory and thinking skills, mainly in older adults?
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Answer: A) Alzheimer’s disease
Alzheimer’s disease damages brain cells and shrinks parts of the brain, especially the hippocampus. It is the most common cause of dementia. Consequently, people first forget recent events and later lose everyday skills. Alois Alzheimer reported the first case in 1906. However, treatments only slow the symptoms. In addition, World Alzheimer’s Day falls on 21 September.
Q18
Which disorder occurs when sudden abnormal electrical activity in the brain causes seizures?
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Answer: B) Epilepsy
During a seizure, groups of neurons fire in an uncontrolled way. As a result, the person may lose awareness or show sudden jerking movements. Moreover, epilepsy is a medical condition, not a curse or a sign of weakness. Doctors use an EEG to record the electrical activity of the brain. Furthermore, most people with epilepsy control their seizures with regular medicines.
Q19
Which neurotransmitter triggers muscle contraction at the neuromuscular junction?
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Answer: D) Acetylcholine
Motor neurons release acetylcholine into the gap between the nerve ending and the muscle fibre. Acetylcholine binds to receptors on the muscle and starts contraction. Then, the enzyme acetylcholinesterase breaks it down quickly. Therefore, the muscle can relax. For example, myasthenia gravis damages these receptors and causes muscle weakness.
Q20
Which heavy metal in polluted seafood caused Minamata disease, a disorder that harms the nervous system?
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Answer: C) Mercury
Minamata disease first appeared in Minamata, Japan, in 1956. A chemical factory released mercury compounds into the bay, and fish absorbed them. As a result, people who ate the contaminated fish developed numb limbs, poor coordination, and vision problems. Consequently, the case became a landmark lesson on industrial pollution. Moreover, the Minamata Convention on Mercury, which countries adopted in 2013, aims to cut mercury pollution.