Nervous System Trivia
0Loading crowd target
0Loading crowd target
7correct to beat the crowd
This nervous system trivia quiz has 97 free questions with answers, and it covers the wiring of the whole body rather than just the brain. You will be asked how the central and peripheral systems divide up, what a neuron's dendrites and axon actually do, why the knee-jerk reflex never bothers to check in with the brain, how many pairs of spinal nerves and cranial nerves you own, and which nerve earns the nickname 'wandering'. There are rounds on the autonomic system (fight or flight versus rest and digest, and the 'second brain' in your gut), on the meninges and cerebrospinal fluid, on the longest and fastest nerves, and on what goes wrong: multiple sclerosis stripping myelin, Parkinson's and dopamine, rabies creeping along nerves, tetanus, Bell's palsy, carpal tunnel and the funny bone. A few questions look at other animals, from jellyfish nerve nets to octopus arms. It suits biology students revising anatomy and physiology, teachers who need a class quiz, nursing and pre-med study groups, and anyone who enjoys human body trivia. Difficulty runs from easy to expert, and every answer was verified against Wikipedia and standard anatomy references before it went in.
30 of 97 questions with answers and explanations. Play the quiz
Q 01In vertebrates the nervous system has two main parts: the central nervous system and which other?
Peripheral
Peripheral nerves link the brain and spinal cord to the rest of the body, and unlike those two they can often regrow after being cut.
Q 02Neurons are typically sorted into three functional types: sensory neurons, motor neurons and what?
Interneurons
Interneurons are the ones in between: they pass signals from sensory neurons to motor neurons and to each other, forming the circuits that process information along the way.
Q 03Which part of a neuron carries impulses away from the cell body, sometimes for a metre or more?
The axon
It leaves the cell body at a swelling called the axon hillock. Dendrites, by contrast, branch profusely but only reach a few hundred micrometres.
Q 04Which nerve, the largest in the body, runs from the lower spine down the back of each leg to the foot?
Sciatic
The sciatic nerve is about 2 cm wide, and a slipped disc pressing on its roots is the most common cause of sciatica, pain that shoots from the buttock down the leg.
Q 05Along with neurons, the nervous system is built from support cells known collectively as what?
Glia
Glia take their name from the Greek for 'glue' because they were long thought merely to hold neurons together; in fact they insulate, feed and defend them.
Q 06Which cells, named after a German physiologist, form the myelin sheath outside the brain and spinal cord?
Schwann
Schwann cells, named after Theodor Schwann, also help a severed nerve fibre regrow, one reason nerves in the limbs recover from injury far better than those of the brain and spinal cord.
Q 07What are the gaps in the myelin sheath, between which nerve impulses appear to jump, called?
Nodes of Ranvier
Nodes of Ranvier let an impulse leap from gap to gap instead of creeping along every bit of the fibre, which is why insulated nerves conduct so much faster than bare ones.
Q 08Which ion floods into a neuron to trigger the rising phase of an action potential?
Sodium
Voltage-gated channels open at a threshold, the interior turns positive, then potassium flows out to restore the resting state. Local anaesthetics work by blocking those sodium channels.
Q 09The fastest myelinated nerve fibres conduct impulses at roughly what speed?
120 metres per second
120 metres per second, about 430 km/h, is reached only by the thickest insulated fibres, such as those reporting muscle position; bare fibres carrying dull, lingering pain are far slower, so that ache arrives last.
Q 10The adult spinal cord is much shorter than the spine, so where does it end?
The lower back
The lower back is where the cord stops, near the first lumbar vertebrae, because the spinal column keeps growing after the cord has finished; only a bundle of nerve roots runs on below.
Q 11What does cauda equina, the name of the nerve-root bundle below the spinal cord, mean in Latin?
A horse's tail
A horse's tail is what the fanned-out nerve roots resemble; squeezing them, as a slipped disc can, may cut off bladder control, which is why it is treated as a surgical emergency.
Q 12Which region of the spine has seven vertebrae but eight pairs of spinal nerves?
Cervical
Cervical nerves number eight because the first leaves above the top neck vertebra and the eighth below the seventh; they are among the 31 pairs that branch off the spinal cord in all.
Q 13Which cranial nerves partly cross so each brain half sees the opposite side?
Optic
Q 21Which division of the autonomic nervous system is built into the walls of the gut?
Enteric
The enteric system can keep the gut churning and moving food along even when cut off from the brain and spinal cord, which is how it earned the nickname 'second brain'.
Q 22Which branch of the autonomic nervous system drives the 'fight or flight' response?
Sympathetic
Sympathetic nerves speed the heart, widen the pupils and open the airways within seconds, while putting digestion on hold until the danger has passed.
Q 23Luigi Galvani found in the 1780s that an electric spark made the legs of which dead animal twitch?
A frog
A frog's leg kicking on his bench convinced Galvani that nerves and muscles run on 'animal electricity', and his name survives in the verb galvanise.
The optic nerves cross right beside the pituitary gland, so a tumour swelling there presses on the crossing fibres and wipes out the outer edges of vision in both eyes.
Q 14Which cranial nerve, the tenth, takes its name from the Latin for 'wandering'?
Vagus
The vagus nerve wanders from the brainstem to the gut and slows the heartbeat, which is why it overreacting to pain, heat or the sight of blood can make a person faint.
Q 15Which cranial nerve, the fifth, carries feeling from the face and powers the chewing muscles?
Trigeminal
The trigeminal nerve splits into three branches for the forehead, cheek and jaw, which is why a dentist can numb half the lower teeth with one injection beside its lowest branch.
Q 16The facial nerve also carries which sense from the front two-thirds of the tongue?
Taste
Taste fibres travel in a branch called the chorda tympani, which crosses the middle ear on its way to the brain, so ear infections or ear surgery can dull taste on one side of the tongue.
Q 17Doctors test which cranial nerve, the twelfth, by asking a patient to stick out their tongue?
Hypoglossal
Hypoglossal means 'under the tongue', and because the nerve on each side pushes the tongue forward, damage to one makes it swing toward the injured side when stuck out.
Q 18Which cranial nerve, the shortest of all, runs only from the lining of the nose to the brain just above?
Olfactory
Olfactory nerve endings line the roof of the nose, and a cold, flu or COVID-19 can knock out the sense of smell; it often returns within a few weeks or months.
Q 19The knee-jerk reflex is the classic example of which kind of reflex arc?
Monosynaptic
Monosynaptic means a single junction: the stretch-sensing fibre connects straight to the motor neuron in the spinal cord, so the leg kicks without any signal having to reach the brain first.
Q 20Why can a reflex like the knee-jerk fire faster than a deliberate movement?
The signal loops through the spinal cord without going to the brain first
The brain still receives the input, but it analyses the signal after the reflex has already happened.
Q 24Roughly how many neurons does the human gut's own 'second brain' contain?
500 million
That is about 0.5% of the brain's count but five times the spinal cord's. It signals with acetylcholine, dopamine and serotonin, just like the brain.
Q 25Inflammation of the three protective membranes that wrap the brain and spinal cord is called what?
Meningitis
Meningitis can be life-threatening if not treated quickly; its warning signs include a stiff neck, a dislike of bright light and a rash that does not fade when a glass is pressed against it.
Q 26Which clear liquid, made inside the brain's ventricles, lets the brain float within the skull?
Cerebrospinal fluid
Cerebrospinal fluid gives a brain of about 1.4 kg an effective weight of only 25 to 50 g, which keeps its own mass from pressing on the tissue and blood vessels at its base.
Q 27Which injection delivers anaesthetic into the space just outside the tough membrane sheathing the spinal cord?
An epidural
An epidural numbs the nerves from just outside the sac of fluid around the cord, so a woman in labour can stay awake while the pain is blocked; a spinal block goes one layer deeper, into the fluid itself.
Q 28Which part of the brainstem controls breathing, heart rate, blood pressure and vomiting?
Medulla oblongata
The medulla oblongata keeps breathing and heartbeat going without conscious thought, which is why an opioid overdose that dulls its breathing centres can stop a person breathing altogether.
Q 29Which small brain structure regulates body temperature and hunger and controls the pituitary gland?
The hypothalamus
The hypothalamus works like a thermostat for body heat, and during an infection chemicals called pyrogens push its setting upward, which is what a fever is.
Q 30Which brain structure, Latin for 'little brain', fine-tunes coordination and timing of movement?
The cerebellum
The cerebellum does not start movements but corrects them as they happen, and thanks to its tiny granule cells it holds more than half of the brain's neurons in a small fraction of its volume.