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The word synapse appears in your Class 10 chapter on control and coordination and again in Class 11 neural control. It feels like a word that has always existed. It has not. A British physiologist chose it in 1897, at a time when no one could see the gap between nerve cells. This post explains how Charles Sherrington reasoned his way to the synapse, what he showed about reflexes, and why his idea of inhibition still matters for your exams.
Who was Charles Sherrington?
Sherrington's Nobel biography records that he was born on 27 November 1857 in Islington, London. He studied medicine at St Thomas's Hospital, then physiology at Cambridge under Michael Foster. Early research took him to Strasbourg, to Spain and Italy to study cholera, and to Berlin to train with Robert Koch. In 1895 he became Professor of Physiology at Liverpool, and in 1913 Waynflete Professor of Physiology at Oxford, where he stayed until he retired in 1936. He was elected a Fellow of the Royal Society in 1893.
The Nobel Prize in Physiology or Medicine 1932 was awarded jointly to Sherrington and Edgar Adrian "for their discoveries regarding the functions of neurons". He died on 4 March 1952 at Eastbourne, according to his Nobel facts page.
How did the synapse get its name?
In 1897 Foster published the seventh edition of A Text Book of Physiology, "assisted by C. S. Sherrington", with Sherrington writing on the nervous system. Describing how the end of one cell's axon approaches the cell body of another, the book says: "Such a special connection of one nerve-cell with another might be called a synapsis." A footnote gives the Greek roots: syn, together, and a verb meaning to clasp. A review in Brain Research Bulletin, Bennett (1999)00094-5), dates Sherrington's adoption of the name to that year.
Why did he need a new word? In his 1906 book The Integrative Action of the Nervous System, based on lectures at Yale, Sherrington set out the argument. Conduction along a nerve trunk and conduction through a reflex arc behave differently. Reflex arcs conduct in one direction only, and nerve degeneration after injury stops at the boundary between one neurone and the next. So, he reasoned, there is likely "a surface of separation between neurone and neurone", and the special properties of reflexes may come from these junctions. "It is convenient to have a term for it," he wrote. "The term introduced has been synapse."
What is reciprocal innervation?
Sherrington's longest-lasting finding is about inhibition. In his Nobel lecture of 12 December 1932, "Inhibition as a Coordinative Factor", he describes experiments from 1892 onwards on the mammalian spinal cord. When a reflex made the flexor muscles of a limb contract, the extensors of the same limb were actively relaxed by the spinal cord. He called this pairing "reciprocal innervation".
Think of your own knee. When you bend it, the hamstrings contract. If the quadriceps on the front of the thigh contracted at the same moment, the two muscles would fight. Sherrington showed that the nervous system prevents this by inhibiting the opposing muscle. He went on to argue that inhibition is not a weak extra but is graded as finely as excitation, and that almost every reflex mixes the two.
His lecture also describes stepping in animals whose spinal cord had been cut off from the brain: the hind limbs alternated between flexion and extension. He could reproduce the rhythm only with a stimulus mixing excitation and inhibition in balance.
How does this connect to what you study?
Your Class 10 NCERT chapter on control and coordination explains reflex actions and the reflex arc, with the synapse as the gap where an impulse passes from one neuron to the next.
Class 11 Biology, Chapter 18, covers electrical and chemical synapses and how transmission at chemical synapses works.
A worked way to answer the classic question, "Why does a nerve impulse travel in only one direction across a synapse?":
State the structure: transmitter is stored in vesicles at the axon terminal of the presynaptic neuron.
State the receptor side: receptors for the transmitter are on the postsynaptic membrane.
Conclude: transmitter is released from one side and detected on the other, so transmission runs one way.
Common mistakes:
Saying Sherrington discovered neurotransmitters. Chemical transmission was shown later, for example by Otto Loewi's frog heart experiment.
Treating inhibition as the absence of a signal. In reciprocal innervation the opposing muscle is actively inhibited.
Writing that Sherrington's Nobel was for the reflex arc alone. The citation says the functions of neurons.
For the full NCERT treatment, read our guide to neural control and coordination.
What can a student take from Sherrington's way of working?
Name what you infer. He gave a name to a structure he could only deduce, and stated why. A clear label for an idea makes it easier to test.
Look at the opposite side. Everyone studied how reflexes excite muscles. He asked what happens to the muscle that does not contract, and found half the story.
Use simple preparations. He studied reflexes with the brain's influence removed, so the spinal cord could be studied on its own. Simplifying a problem before solving it is a skill you can use on any long question.
If the path from receptor to effector still feels abstract, the Fermi Simulation Lab has interactive simulations for ideas that are easier to see than read.
Next step: draw a reflex arc for withdrawing your hand from a hot object, then add a second motor neuron that is inhibited, and label which muscle relaxes.
