Sunday, March 15, 2009

Neuron: sinew, tendon, nerve; Nervus: sinew, vigor

Many good returns, fans of etymology, Greek and Latin roots, and medical terminology! As with all disciplines, the learning of specialized vocabulary in the medical field can take years, but a great way to get a true leg up on learning this vast medical lexicon (which only gains more and more terms, or neologisms, on a daily basis) is understanding the Greek root words (and to a smaller extent the Latin roots) that make up most of medical vocabulary. You will recall that in my last two posts, I wrote about common medical terms for the Greek root for blood (haima, haimatos) and Greek roots for hematology itself, which is the word origin for numerous medical terms. It is now time to move on to discuss the Greek and Latin roots of the infrastructure of the central and peripheral nervous system:

Neuron—sinew, tendon, nerve {neuro-}
Nervus (Lat.)—sinew, nerve, vigor, determination

Let's take a look at the Latin root first. A nerve, derived from the Latin root nervus: sinew, nerve, indeed is etymologically a sinew or tendon along which electrochemical impulses travel that allows coordination and communication within the body, the core of which is the central nervous system, composed of the largest mass of nerves, the cerebrum, and the spinal cord. These nervous (of or pertaining to a nerve) cables, as it were, are comprised of neurons (technically the peripheral axons), and are only part of the peripheral nervous system, not the central nervous system, where the nerves are known as tracts. The body is able to communicate with itself via this highly complex coordinate system via electrochemical impulses which move along the axons, much as a house or computer is wired to allow electricity to flow through it.
One can be said to be nervous when one feels apprehensive, shaky, or agitated due to imminent expectation (nervosity is the state of being nervous); when one's nerves completely get the better of one, a person can head for what is popularly known as a nervous breakdown, a severe emotional collapse that may or may not be caused directly by the nerves; it is interesting to note that this parlance is purely social in usage, and is not recognized by the medical or scientific community. The optic nerve links the retina (via the Latin root rete—net; the retina is a net made of rods and cones that catches photons, related to reticulated python and reticulated giraffe, both of which have a netlike pattern on their epidermis) to the brain, where images that the eye receives are processed and turned into the images that we "see." The auditory nerve links the ears with the brain, where sounds are processed, the olfactory nerve from the mucus membranes of the nose to the cerebrum.
If one is enervated, one has lost energy or "vigor": The hiker was so enervated by his arduous ascent up Mauna Kea that he felt as if all his ‘nerves’ had been taken ‘out,’ leaving him limp as a warm cherry Knox Block. A situation can be unnerving if one feels totally out of one's element and experiences clear and present danger, hence being deprived of one's courage or chutzpah or fortitude.
In regards to pure medical anatomy, the Greek root neuron is much more frequently in use. Neurons, also known as nerve cells, not only consitute nerves, but also are the electrochemical cells that comprise the central nervous system (brain and spinal column) and nerves; each neuron possesses a single axon (the primary transmission lines that allow communication between neurons) and one or more dendrites (via the Greek root dendron: tree; witness dendrochronology, the determining of the age of a tree by counting its rings). Neural, surprisingly enough, refers to a nerve (again, a bundle of neurons) or the nervous system, whereas the word neuronal or neuronic refers to individual neurons themselves. Neuralgia is severe and sharp pain that exists within a nerve or bundle of nerves (consider the Greek root algos: pain; it gives us such words as analgesic: a medicine that takes "pain away;" nostalgia the "pain of home;" and odontalgia, a "toothache."). Neuritis is inflammation of a nerve, which can cause such symptomatology as severe pain, muscle atrophy, and loss of reflexes {note that the Greek suffix -itis, inflammation, is used ubiquitously in such words as tonsillitis, mastitis (inflammation of the breast), laryngitis (of the larynx), tendonitis (most commonly of the Achilles tendon), and nephritis (of the kidney)}.
What sounds more euphonic to you, a nervologist or a neurologist? Nervology or neurology? The Greek root certainly has much more cachet, and is coupled with a Greek suffix (logos—word, speech, study, saying, reason, thought, calculation, ratio, a progenitor of thousands of different disciplines, such as biology, psychology, limnology, eschatology, etc. etc.); it is considered linguistically gauche to mix Latin with Greek roots, although it is done often. My next post will focus on the study of neurology and the disciplines that neurologists, or those physicians that study the nervous system and its related ailments (neuropathology) specialize in.

Interested in even more English vocabulary words that come from the Greek and Latin roots for nerve, or interested in perusing three pages of English derivatives that come from the Greek root logos? Are there other common words that come from the Greek root dendron, tree, or algos, pain? What are all the inflammations that can arise within our most fascinating bodies, discussed in the word tree -itis—disease of, inflammation of? All of the word roots mentioned above are accessible via the etymology site , on which you may want to check out the most comprehensive Greek and Latin roots dictionary available today; a Greek and Latin roots poster is also available, which beautifully illustrates not only the sheer power of Greek and Latin roots as they form the very semantic structure of the English language but also contains a prolific number of GRE and SAT vocabulary words, and a vast host of medical vocabulary.  Or, if you're looking to learn vocabulary for the SAT or GRE verbal section, check out, where vocabulary is taught to you via an Adaptive Reinforcement Engine in a fun and engaging way which at the same time enhances your memory..