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During an annual “well-woman” visit, it is customary to perform a pelvic exam to screen for cancers of the reproductive system. These cancers include uterine cancer, ovarian cancer, and cervical [Origin: Latin, cervix (neck)] cancer. The last one is especially noteworthy, thanks to the development and implementation of the most successful cancer screening test in medical history: the Pap test. This screening test swabs the cervix of the uterus and assesses the morphology of the obtained cells. If the cells are atypical, the gynecologist obtains a cervical biopsy to further assess the situation and take the appropriate measures.

What is the etymology of “Pap” in “Pap test?” Turns out that this is not from an ancient Greek root; rather, it’s from a modern Greek physician! Georgios Papanikalaou (1883-1962) drew inspiration from Walter Hayle Walsh (1812-1892) when the latter reported on the observation of malignant cells under the microscope in certain lung diseases. In 1928, Papanikalaou presented his technique to an audience of physicians:

  1. Gather cellular debris from the vaginal tract
  2. Mount it on a microscope slide
  3. Stain it with the Pap stain (haematoxylin counterstained with OG-6 and eosin azure)

Left: Georgios Papanikalaou, right: Aurel Babeş

Even though Papanikalaou first developed and demonstrated the use of this technique, it turns out that another physician—Aurel Babeş—made similar progress regarding the microscopic analysis of malignant cells. Babeş used a platinum loop to collect cells from the cervix and mounted the sample on a microscope slide. Babeş published before Papanikalaou, but Papanikalaou used the technique in hospitals before Babeş published. For this reason, we give it the name of “Pap test,” but in Romania, it is called the “Babeş-Papanikalaou test” in honour of Babeş’s independently-developed method. In Spanish, the “Pap” is said in full, i.e., it is “la prueba de Papanikalaou”: the test/probing of Papanikalaou!

There is another gynecologic eponym [Origin: Greek, epi- (on/upon) + onoma (name)] that most people don’t readily recognize. Gabrielle Falloppio (1523-1562) was an Italian physician and anatomist who primarily explored the anatomy of the head: he described the inner ear, the middle ear, the mastoid cells, and the circular & oval windows, among many other structures. He also studied the reproductive systems of both males and females—including the structures that connect the ovaries to the uterus. For those that prefer non-eponymous nomenclature, an alternative name for the Fallopian tubes is uterine tubes. Note that Falloppio’s name is spelled with 2 “p”s, but we only use one “p” in Fallopian! (In Spanish, it is cut down by an extra “l,” spelled “Falopio.”) Falloppio also advocated the use of condoms to prevent syphilis and conducted an early clinical trial of sorts; he observed that the approximately 1100 men who used condoms and reported to him did not contract syphilis.

Left: Gabriele Falloppio, right: a 16th century prophylactic device

If the Fallopian tubes and the ovaries are afflicted with cancer and need to be removed, what words do we use to describe the surgery? For the Fallopian tubes, we use salpingectomy, and for the ovaries, we use oophorectomy.

Salpingectomy
Origin: Greek, salpinx (trumpet) + ek- (out of) + temnein (to cut) + -ia (condition of)
A cutting out of the trumpet, i.e., the Fallopian/uterine tube
N.B. (nota bene): in Spanish, they are called “las trompas de Falopio”: tube/horn of Falloppio!

Oophorectomy
Origin: Greek, oion (egg) + pherein (to carry) + -ectomy (a cutting out)
A cutting out of the egg-carrier, i.e., the ovary

And if both entities need to be removed, we call it a salpingo-oophorectomy. This term denotes that only one ovary and one Fallopian tube is excised; if both are excised, we append bilateral [Origin: Latin, bi- (two) + latus (side)] to the procedure for a bilateral salpingo-oophorectomy.

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Who doesn’t love a good cup of joe? Coffee is a much-beloved beverage that we drink for a variety of reasons, chief amongst them taste and stimulatory effects. Coffee was supposedly first cultivated in Ethiopia, and the first credible evidence of its consumption by humans is from the port town of Mocha in Yemen in the mid-15th century. There is a whole host of etymology and history to talk about, but let’s start with the word coffee itself:

Coffee
Origin: Arabic, qahwah, from qaha (to lack hunger)
So named for the age-old observation that coffee, via caffeine, blunts the appetite

As for the phrase, “a cup of joe,” there are a number of possible etymologies, but the one that I prefer is the shortening of “cup of jamoke”:

Jamoke: Java + Mocha
Java is a country that produces a lot of coffee bean
Mocha (Arabic: al-muka) is the port city in Yemen that was a huge coffee marketplace

mocha rev

European factories at the port of Mocha, 17th century

I would like to clear up a number of misconceptions about different styles of coffee. We have cappuccinos, espressos, mochas, lattes, and many more. Their etymologies may help you differentiate them! The first one that we build off of is espresso.

Espresso
Origin: Italian via Latin, ex- (from/out of) + primere (to press)
Coffee produced by forcing (“pressing”) nearly-boiling water through fine coffee grounds

This form of coffee is the base for the others that we commonly see. To produce cappuccinos and lattes, we need a base of espresso. A cappuccino is 1/3 espresso, 1/3 hot milk, and 1/3 foamed milk. Where does the word come from?

Cappucino
Origin: Italian, cappuccino (of the Capuchin friars)
So named because of the resemblance of a cappuccino’s color to the friars’ garments

cappuccino rev

Left, Portrait of a Capuchin Monk by Rubens; right, his namesake

Contrast a cappuccino with a simple café latte, which simply translates to “coffee with milk.” The coffee in question is espresso. Different establishments use different ratios of coffee to milk, but if we want to be rigorous with our etymological descriptions, a cappuccino is thus considered a subset of café latte. Now, a macchiato is something that is greatly misunderstood. It is a drink with hot milk at the bottom and a small amount of espresso at the top. Its etymology:

Macchiato
Origin: Italian, macchiato (marked)
So called because the espresso “marks” the hot milk at the bottom

Again, different people will use different ratios, so a quantitative definition is difficult, but that’s the general idea. Finally, out of our current list there is the mocha. As you might imagine, this is the very same Mocha that I presented earlier, i.e., the port town in Yemen that was a large hub for coffee in Ottoman times. Supposedly, the coffee beans that were exchanged in Mocha often had a chocolate taste to them, which is why we use the term mocha these days to refer to any coffee with a chocolate flavor or coffee with chocolate syrup.

What other types of coffee are you interested in learning about or would like to share? Leave a comment below and let’s discuss!

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Animals were of prime importance in the classical world: agriculture in the Roman Empire depended on domesticated oxen (L., bos) to plow the fields, crowds of thousands cheered on the races at the Circus Maximus, as drivers atop their chariots urged on the fastest horses (L., equus) in the land, and sacrifices of sheep (L., ovis), and pigs (L., porcus) were necessary to please the gods. So too were animals important to ancient scientists and physicians. It was the dissection of and the experiments on animals that formed the basis for early understanding of human anatomy and physiology. In addition, there are countless anatomic terms whose etymologies derive from the Greek and Latin names of animals.

Cauda equina
Origin: Latin, cauda (tail) + equus (horse)
Horse’s tail

cauda equina

Sitting within and protected by the vertebral column, the spinal cord consists of nerve cells and their extensive myelinated tracts that carry motor, sensory, and autonomic data to and from the brain. One would think that the spinal cord extends all the way to the bottom of the vertebral column, but in fact it stops looking like a cord at the level of the L2 vertebra in adults. At that point, it gives rise to the so-called cauda equina where individual nerves arising from the lower part of the spinal cord descend down the vertebral column until they exit through the proper foramina. It’s no wonder then why lumbar punctures must be done below L2: the individual nerves of the cauda equina can easily accommodate the lumbar puncture needle unlike the large-diameter spinal cord. So the next time you consent a patient for an LP, be sure to ask yea or neigh.

Coccyx
Origin: Greek, kokkux (cuckoo)

sacrum

The vertebral column consists of seven cervical, twelve thoracic, and five lumbar vertebrae. The primary role of these bones is to protect the spinal cord. However, their articulations allow flexion, extension, lateral motion, and rotation of the back, explaining their derivation from vertere (L., to turn). There are two more bones that lie below L5. The sacrum, which the Romans called the os sacrum (L., sacred bone) and which the Greeks named the hieron osteon (Gk., sacred bone), sits within the pelvis and allows the sacral nerves of the cauda equina to exit through its foramina. It’s not clear why this bone was considered “sacred.” One thought is that its sacredness derives from its location in the pelvis and therefore an association with reproduction. Another theory suggests that the ancients used this bone during sacrificial ceremonies. Finally, below the sacrum sits the coccyx, the small bony remnant of a vestigial tail. The ancient anatomists who named this bone thought that, when viewed from its side, it bears resemblance to a cuckoo’s beak.

Tragus
Origin: Greek, tragos (goat)

traigus

The tragus is that small piece of cartilaginous tissue situated next to the opening of the ear canal. And for some strange reason, it’s derived from the Greek word for goat. Perhaps some Greek anatomist had particularly hairy ears and thought it resembled the hair on a goat’s chin. Whatever the reason, the association with goats definitely stuck: the medical term describing hair on the ears is barbula hirci, literally meaning “little beard of the goat” [L., barbus (beard) + hircus (goat)]. No kidding.

Concha
Origin: Greek, konkhe (mussel, shell)

concha

Within the nose lie the superior, middle, and inferior nasal conchae. These long shelves of bone on the lateral aspects of the nasal cavity are covered with mucosa and supplied by a rich network of blood vessels. Their most important function is to warm and humidify the air as it passes from the nasal cavity to the lungs. If I look really hard, I can make myself believe they look like little mussels. Astute readers will notice that concha also appears in the labeled anatomy of the outer ear: concha also describes the fossa next to the opening to the ear canal.

Pes Anserinus
Origin: Latin, pes (foot) + anser (goose)
Goose’s foot

pes anserinus

Three muscles of the leg, the gracilis [L., gracilis (slender)], sartorius [L., sartor (tailor)], and semitendinosus [L., semi (half) + tendere (to stretch)], give rise to tendons that travel in parallel before attaching to the same location on the tibia. The ancient anatomists who saw this arrangement must have been reminded of the tripartite webbed feet of the goose and named it as such. There is a clinical condition called “pes anserinus pain syndrome,” also known as “pes anserine bursitis,” that describes pain around these tendons on the medial side of the knee. Interestingly enough, pes anserinus is not only a structure in the leg: it also is another name for the parotid plexus, where the facial nerve branches after exiting the stylomastoid foramen.

Recurrent Laryngeal Nerve

galen dissection

Galen demonstrating the effects of the recurrent laryngeal nerve during the dissection of a pig

The recurrent laryngeal nerves are branches of the vagus nerves that control nearly all of the intrinsic muscles of the voice box. Therefore, injury to one or both may cause hoarseness or even a complete inability to phonate. The etymology is nothing to write home about, but the story of their discovery definitely is. The famed Greek physician Galen, while conducting an experiment on a live, strapped-down pig, accidentally cut both laryngeal nerves; the pig continued to struggle but completely stopped squealing. He ultimately traced out the path of the nerves and confirmed that they originated from the vagus nerves. He noted that “there is a hairlike pair [of nerves] in the muscles of the larynx on both left and right, which if ligated or cut render the animal speechless without damaging either its life or functional activity.” Galen held a public demonstration of his experiment in Rome that was well-attended by distinguished politicians and scholars of the time. Those readers interested in learning more can read the article “Galen and the Squealing Pig,” linked here.

Thanks for taking a trip to the zoo with me. I’m off to see the capybara exhibit.

P.S.: Can you think of the English adjectives derived from the Latin words mentioned in the first paragraph? As a bonus, what about the adjective that describe wolves? Fish? Ducks?

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When we think of the deadliest diseases of the world, things like Ebola and the Black Death come to our minds. However, it turns out that cardiovascular disease (CVD) is the world’s leading cause of death in this day and age. In the 1970s, we were convinced that CVD was caused by dietary fat. Indeed, there was a public campaign to stamp out fat and replace it with carbohydrates. People didn’t realize that fat wasn’t the issue. Rather, fat has the highest calorie/mass ratio (9 calories per gram) and excess consumption of fat leads to obesity and its milieu of problems, including CVD. The food industry replaced fat with carbohydrates to meet this craze, and “fat-free” foods were instead pumped with sugar. Of course, calories are calories—and when people consumed these foods in earnest, not much changed with regards to the incidence of CVD.

So what exactly is fat? Chemically, fat is a glycerol molecule + three fatty acids. Fatty acids are long-chained aliphatic carboxylic acids that are either saturated (only single bonds) or unsaturated (one or more double/triple bonds). Quick aside: in popular culture, we hear about “omega-3 fatty acids” and “omega-6 fatty acids.” This refers to the position of the first double bond in the fatty acid, with the omega position being the last carbon in the chain (see picture below). So an omega-3 fatty acid is a fatty acid that has its first double bond on the 3rd carbon from the omega position.

Glycerol
Origin: Greek, glykeros (sweet) + –ol (chemical suffix for alcohols)
So named because glycerol is, in fact, sweet (and is an alcohol)

triglyceride glycerol

Aliphatic
Origin: Greek, aleiphar (oil)
Refers to hydrocarbons that do not contain benzene rings

What about the term lipid [Gk. lipos (fat)]? In the vernacular, people equate the word “lipid” to “fat,” and its etymology certainly vindicates such an equation. But of course, we must be rigorous with our definitions. To start, fats (i.e., triglycerides) are certainly a lipid subclass. Other subclasses include waxes (fatty acid esters such as beeswax; article’s featured image) and sterols (isoprene-derived steroids such as cholesterol). One classical definition of a lipid is the following: lipids are hydrophobic (some also include amphiphilic) small molecules that can dissolve in organic solvents but not water.

Hydrophobic
Origin: Greek, hydor (water) + phobos (fear)
Fear of water, i.e., not dissolvable in water or other polar solvents

Amphiphilic
Origin: Greek, amphi – (both) + philia (love)
Love of both water and fat, i.e., dissolvable in polar and nonpolar solvents

For those who love math, recall that for a statement to be proven true, it must be true in all instances. For a statement to be proven false, one need only provide a counterexample. So my counterexample for this definition of lipid is the molecule carbon tetrachloride (CCl4). CCl4 is a small molecule, it is hydrophobic, it dissolves in organic solvents, and it doesn’t dissolve in water. Now, to patch the definition up, one can make an addendum to include “naturally-occurring.” Needless to say, CCl4 is not naturally-occurring. Is there another definition of lipid that you prefer? Let me know in the comments!

lipids

Before ending this post, I would like to touch on the significance of fat in disease. There are a number of disease states that manifest with malabsorption; one of them is coeliac disease. The diarrhea that coeliac patients experience after ingesting gluten is more accurately termed steatorrhea:

Steatorrhea
Origin: Greek, stear (fat) + rhein (to flow)
Flow of fat (through the intestines), i.e., fat in the stools

How can you identify steatorrhea? If the stool is especially foul-smelling and sticks to the sides of the porcelain shrine, you’ve got yourself a flow of fat.

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Pneumonia is one of those medical conditions that is constantly thrown around without being rigorously defined—and as we all know by now, rigor is absolutely paramount in my view of academic medicine and medical etymology. Let’s start by looking at the word from an etymological standpoint:

Pneumonia
Origin: Greek, pneumon (lung) + –ia (condition of)
Condition of the lung

Well, that certainly wasn’t very helpful—at least not at first glance. There can be many conditions of the lung that are called “pneumonia” and the classic case of a lung infection is merely one of them. Compare pneumonia to pneumonitis:

Pneumonitis
Origin: Greek, pneumon (lung) + -itis (inflammation of)
Inflammation of the lung

There are many inflammatory conditions of the lung, but only a few of them are called “pneumonitis” because pneumonitis is considered to be inflammation of the lung tissue itself (the lung parenchyma). There are some who then consider pneumonia to be inflammation of the air sacs in the lungs (the alveoli). This makes sense for the most part; the bacteria, viruses, fungi, and parasites that can cause pneumonia would cause alveolar inflammation.

lung diagram

To put things in perspective, when somebody is admitted to the hospital for pneumonia, the classic picture is someone who acquires a bug, and said bug colonizes the alveolar space. The resulting “mass” that forms (usually in one lobe of the lung) is called a consolidation:

Consolidation
Origin: Latin, con- (with) + solidus (solid)
With solid, i.e., things that aggregate to form a “solid”

For these “classic” pneumonias, we can call them community-acquired pneumonia (CAP), hospital-acquired pneumonia (HAP), and the like. Some bugs associated with the former are things like Streptococcus pneumonia and Pseudomonas aeruginosa, and some bugs associated with the latter are things like Staphylococcus aureus and Haemophilus influenzae. (Stay posted for microbiological etymology!)

But it turns out that this isn’t the whole picture. Pneumonia is indeed as general as its etymology suggests, for there can be inflammatory and fibrotic conditions of the lung—and both classes can fall under the term “pneumonia.” (Generally, inflammation is caused by the infiltration of white blood cells and fibrosis is caused by the production of excess connective tissue, e.g., collagen.) Thus, as a counterexample to the definition that pneumonia is simply the inflammation of the alveoli, we have something called usual interstitial pneumonia (UIP). It is a form of interstitial lung disease in which the tissue between the alveoli is fibrosed with collagen.

uip ctThe classic “honeycomb lung” appearance of UIP on CT scan

To end this post, I posit my generalized definition of pneumonia: pneumonia is a principally inflammatory or fibrotic condition of the lung. By formalizing this definition of pneumonia, I am faithful to the etymology and make pneumonitis a subset of pneumonia. Note that I use the word “principally” in front of inflammatory—the reason why is that cancers of the lung can cause inflammation, but cancers are not considered to be pneumonias by any definition or practice.

In another post I will discuss the classic methods of diagnosing “normal” (generally bacterial) pneumonia and the etymologies of these techniques. Here is a small teaser: one of the terms involves the Greek word for goat! Can you guess which one? Leave a comment below.

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Thanksgiving is upon us, and next to the fastidious references to pumpkin spice lattes and the like, the reference that we perpetuate and perhaps look forward to is that of the classic Thanksgiving postprandial somnolence.

Postprandial
Origin: Latin, post- (after) + prandium (meal)
After a meal, especially dinner

Somnolence
Origin: Latin, somnus (sleep)

Now, what is the soporific agent responsible for sending us on our merry way to the arms of Hypnos? Most people would tell you that copious amounts of tryptophan are responsible. Tryptophan is one of the 20 amino acids that are used to synthesize proteins in our bodies, and it is said to be abundant in turkey meat.

Tryptophan was first isolated in 1901 by Frederick Gowland Hopkins through the hydrolysis of casein; casein is one of the proteins that are abundant in milk. (Interesting aside: casein has an affinity for the molecule capsaicin, which is found in chili peppers. This is why dairy products neutralize the spice from peppers.) Hopkins conducted an animal study in which he removed tryptophan from the diets of mice. He found that tryptophan was necessary for the mice to grow, and concluded that tryptophan is one of the “essential” amino acids, i.e., it must be obtained through the diet. In 1912, he conducted another animal study in which he supplied mice with pure proteins, fats, carbohydrates, and minerals. He found that the mice did not grow, and postulated that there exist unidentified “accessory food factors” necessary for growth and survival. These “accessory food factors” are better known to us now as vitamins, and for this realization, Hopkins was awarded the Nobel Prize in Physiology or Medicine in 1929.

hopkins tryptophan

Now, regarding tryptophan: where does the word come from? Let’s start with some etymology:

Tryptophan
Origin: Greek, trypsin (digestive enzyme) + phanein (to show)
Something that is shown when trypsinized

Thus, tryptophan is so named because it is “shown” (produced) when proteins are digested with the enzyme trypsin. The etymology behind trypsin is rather cool as well:

Trypsin
Origin: Greek, tribein (to rub)
So named because it was first obtained with rubbing the pancreas

Anyways, it turns out that tryptophan is not the agent responsible for the ol’ Thanksgiving food coma. It has been shown that chicken and beef contain similar quantities of the amino acid. Instead, it is the large amount of carbohydrates ingested through classic Thanksgiving dishes such as mashed potatoes, yams, stuffing, etc. I won’t bore you with the posited mechanisms behind this, but there are a number of online resources that could fill you in if you so choose. Let us part with another fun Thanksgiving etymology:

acholeus rev

The Banquet of Acholeus by Rubens (1577-1640)
(Heracles fought against Acholeus for the hand of Deianeira, and when Acholeus transformed himself into a bull, Heracles took one of his horns. Acholeus offered him the horn of the goat Amalthaea, and Heracles in turn gave it to the Naiads who transformed the horn into the cornucopia)

Cornucopia
Origin: Latin, cornu (horn) + copia (wealth)
Horn of wealth, taken to mean horn of plenty
In classical mythology, it was an infinite source of food and drink from the goat Amalthaea

And thus I wish you all a Happy Thanksgiving, and may it be filled with a cornucopia of food, family, and fun.

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Playing the singular/plural game is always fun (at least to me), so here is a short aside with a few of my favorites that relate to the topics I lectured on these past few weeks:

  1. Apparatus → apparatus
    Origin: Latin, ap- (toward) + parare (to set)
    A piece of equipment, i.e., something that “sets you toward something”
  1. Foramen → foramina
    Origin: Latin, forare (to bore)
    An anatomical hole or opening
  1. Fossa → fossae
    Origin: Latin, fodere (to dig)
    An anatomical ditch, with only one open end
  1. Octopus → octopodes
    Origin: Greek, octo– (eight) + podos (foot)
    The animal with eight feet

Can you think of the plurals for these words? Leave a comment below!

  1. Plexus
  2. Isthmus
  3. Duodenum
  4. Platypus
  5. Rhinoceros (!)

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There are a number of ways of diagnosing disease: tissue biopsy, symptom matching, and of course, clinical signs. People often use the latter two terms interchangeably, especially since they are often paired together via the phrase “signs and symptoms.” But rigorously, these two words refer to two different things. Perhaps their etymologies will help differentiate them:

Sign
Origin: Latin, signum (sign/image)
Something the clinician notes in during a clinical encounter

Symptom
Origin: Greek, sym- (together) + piptein (to fall)
Something a patient reports to the clinician; something that “falls together” with something else

In other words, symptoms are subjective experiences while signs are objective experiences. For example, if I tell my doctor I have a fever, that is considered a symptom, but if he or she were to measure my temperature and find it elevated, it would be a sign. Another good example: pain is a symptom, since the perception of pain is unique to each patient. Tenderness, however, is a sign, since it is elicited by a clinician, e.g., applying pressure to the abdomen and eliciting an “ouch!”

stigmata rev

St. Francis Receives the Stigmata, by Antoni Viladomat (1678-1755)

There is another pair of terms that are often used together that is also often conflated. These words are stigma (plural stigmata) and sequela (plural sequelae). A stigma is a readily-visible (cutaneous or otherwise) or discernable sign that is characteristic of some disease. A classic stigma of liver disease is jaundice.A sequela, on the other hand, is an abnormal state or complication that results from a previous disease. A classic sequela of diabetes is diabetic nephrophaty. The etymologies of these words are relatively straight-forward:

Stigma
Origin: Greek, stizein (to mark/tattoo)

Sequela
Origin: Latin, sequi (I follow)

Interestingly enough, the word “stigmata” is also used in theology to refer to the bodily marks or sensations of pain associated with the crucifixion [Origin: Latin, crux (cross) + figere (to fix/bind)] of Jesus. Those who bear these stigmata are called “stigmatics” or “stigmatists,” and a common motif in classical painting is St. Francis of Assisi’s reception of the stigmata (see above). St. Francis supposedly received the stigmata of Christ for his great piety during the Feast of the Exaltation of the Cross after a forty-day fast.

Regarding jaundice, a stigma of liver disease, we know it to be the yellowing of the skin due to increased levels of bilirubin. Jaundice can, of course, be caused by a number of other conditions, e.g., deficiencies in certain enzymes (cf. Gilbert syndrome). There is one part of the body that is not said to be jaundiced when yellow; that honour falls on the eyes. When the eyes turn yellow due to, say, liver disease, we call it scleral icterus.

icterus rev

Jaundice
Origin: Latin, galbinus (yellow/yellow-green)

Icterus
Origin: Greek, ikteros
A bird said to cure jaundice when spotted

Hence we call it scleral icterus because it is with our eyes that we see the ikteros and become cured of our jaundice!

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Enzymes are biological catalysts that allow a host of chemical reactions to take place in organisms. They can also be used in synthetic chemistry to perform difficult reactions, e.g., forming carbon-carbon bonds. Enzymes (and more generally, all catalysts) do this by lowering the activation energy of a reaction and stabilizing the transition state. Where does the word enzyme come from?

Enzyme
 Origin: Greek, en– (in) + zyme (leavened)
Something leavened in

Louis Pasteur (Pasteur pipettes, pasteurization, etc.), a titanic French chemist of the 1800s, was studying the fermentation of alcohol by yeast.  He postulated that the agent responsible for fermentation was a “vital force,” and that only living organisms could perform the task. Wilhelm Kühne coined the term “enzyme” to refer to the process, but it was Eduard Büchner (Büchner funnel) who showed that cell-free yeast extracts could still ferment sugar into alcohol. For this, Büchner received the 1907 Nobel Prize in Chemistry. He named the agent responsible zymase.

pasteur and buchner

Left: Pasteur; Center: Kühne; Right: Büchner

Zymase
Origin: Greek, zyme (leavened) + –ase (enzyme suffix)
That which cleaves “leavened,” i.e., the substrate is from the yeast

Following Büchner’s convention, we use the suffix –ase to denote the substrate of an enzyme, e.g., an enzyme that catalyzes a reaction involving a peroxide is called a peroxidase. Note that this convention is not used for all enzymes. Here are some enzymes with interesting etymologies that are important for digestion:

Amylase
Origin: Greek, a– (without) + myle (mill) + –ase
That which cleaves something unmilled, i.e., starch

Pepsin
Origin: Greek, peptein (to digest)
That which cleaves proteins into peptides

Lipase
Origin: Greek, lipos (fat) + –ase
That which cleaves fats, e.g., triglycerides

Some enzymes require organic or inorganic cofactors in order to function. The organic cofactors can either be prosthetic groups, which are covalently bound to the enzyme, or they can be coenzymes, which are cleaved from the active site during the reaction. Some cofactors may be involved in allosteric modulation; here, an ion or molecule binds to an area away from the enzyme’s active site to modulate its activity.

biotin cofactor

Biotin (left) is a cofactor of pyruvate carboxylase (right)

Allosteric
Origin: Greek, allos (other) + stereos (solid, taken to mean 3D shape/position)
Pertaining to another space/position

Are there any cool enzymes with puzzling etymologies that you can think of? Leave a comment below and let’s explore!

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I think it’s safe to say that we’re all fairly familiar with our five senses: seeing, hearing, touching, tasting, and smelling. But what self-respecting etymology blog calls it a day with those terms? We need to be more rigorous!

sight                →   vision          →       Latin, videre (to see)
hearing           →   audition      →        Latin, audire (to hear)
touch              →   taction        →        Latin, tangere (to touch)
taste               →   gustation    →        Latin, gustare (to taste)
smell               →   olfaction     →       Latin, olfacere (to smell)

There are even fancier terms for these, such as ophthalmoception, but let’s not get too carried away.

Ophthalmoception
Origin: Neo-Latin, ophthalmos (Gk. eye) + recipere (L. to receive)
To receive from the eye, i.e., vision

Bruegel_d._Ä.,_Jan_-_Allegory_of_Sight_and_Smell_-_1618

The Sense of Sight and Smell, by Brueghel the Elder

Without getting into fantastical and/or esoteric discussions of the legendary sixth sense, it turns out that we have much more than five senses. These “nontraditional senses” depend on special receptors in our bodies, and some of them don’t rely on specific sensory apparatus (singular: apparatus) (no, that’s not a joke). One classic example is proprioception, which is the ability to know where one’s body is in three-dimensional space. Unconscious proprioception relies on the cerebellum, whereas conscious proprioception relies on the dorsal column/medial lemniscus (DCML) tract to the parietal lobe.

Proprioception
Origin: Latin, proprius (one’s own) + -recipere (to receive)
To receive one’s own, i.e., information about one’s own body

What about the sensation of pain? Pain is a complex topic and much research has gone into it. Our current understanding of pain is that pain is not directly sensed by the body; rather, it is “interpreted” by the body after exposure to a noxious stimulus. Noxious stimuli stimulate peripheral nerves and the central nervous system generates pain. The detection of noxious stimuli is done via nociception by nociceptors.

Nociception
Origin: Latin, nocere (to hurt/harm) + recipere (to receive)
To receive hurting/harm, taken to mean pain

Again, rigorously, our bodies to do not directly sense pain—they sense noxious stimuli, and develop pain in response. Also note that it is difficult to assign a definition to pain, for it is a subjective phenomenon: we all respond to noxious stimuli differently.

descartes rev

Descartes thought that animals lacked consciousness—and thus could not feel pain

I was given a request for the adjective forms of some of the nontraditional senses, but I couldn’t find many of them in any dictionaries. I did find the adjective form for proprioception: proprioceptive. Using this convention, here is a list of adjectives:

proprioception             →        proprioceptive
nociception                  →        nociceptive
chronoception             →        chronoceptive
thermoception             →        thermoceptive

I haven’t discussed the last two terms on this list; what are their etymologies? Leave a comment below with your answer!