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Anatomy Lesson #48: The Big Guy! – G.I. Tract 5

By Dr. Karmen L. Schmidt

Greetings fellow travelers! Welcome to today’s Anatomy Lesson #48, “The Big Guy,” better known as large intestine. Much is known about large intestine but today’s lesson covers only a tad; otherwise, the lesson would rival one of Diana’s big books! <g>  This topic may prove uncomfortable for some, but I hope you lasso any reservations and read this fascinating stuff. For those not sure, Jamie appears to give a wee warning before the most – ahem – personal bits. The good news: Outlander quotes, scenes, and book spoilers await. Yay!

Last lesson, Anatomy Lesson #47, “Brave Bowels – Gurgly Gut!” – GI Tract, Part 4, we learned that small intestine ends after ileum, the site where large intestine begins.

Divisions: As always, anatomical descriptions and definitions are a must! Large intestine is shorter (5 ft) than small intestine (20 ft) but its diameter is larger (3”) compared with the little guy (1-2”), hence the name. Large intestine is divided into the following regions (Image A):

  • vermiform appendix (cream & green)
  • cecum (yellow)
  • colon
    • ascending colon (green)
    • transverse colon (mauve)
    • descending colon (dark blue)
    • sigmoid colon (light blue)
  • rectum (purple)
  • anal canal (not labelled)

Image A

Other Features: Large intestine also exhibits three other important anatomical features (Image B):

  • ileocecal valve – opening between ileum and cecum
  • right colic (hepatic) flexure – near the right lobe of liver
  • left colic (splenic) flexure – near spleen

Image B

Location: Large intestine lies in the abdominal cavity partially covered by small intestine. Removing small intestine requires cutting the root of the mesentery (Image C – red arrow) – this mesentery suspends small intestine from the posterior abdominal wall (Anatomy Lesson #47, “Brave Bowels – Gurgly Gut!” – GI Tract, Part 4).

Now, lifting greater omentum and transverse colon reveals all parts of the large intestine, except anal canal (Image C).  The mesentery (yellow in Image C) envelopes most of large intestine, securing the parts in their respective positions and containing blood and nerve supplies. Appendix, cecum, and ascending colon typically sit on the right side of the abdominal cavity – descending and sigmoid colons are on the left. Transverse colon hangs between right and left colic flexures. Rectum lies in the midline of the pelvic cavity.

Understand that exceptions to this arrangement do occur. One rare congenital condition, situs inversus totalis, happens once in every 10,000 people. Here, all abdominal and chest organs are flipped 180°. So, for example, appendix lies in lower- left abdominal cavity. Competent health practitioners must keep such rarities in mind while assessing patients.


Image C

Now, onto specific parts of large intestine.

Cecum: The term, cecum or caecum (British spelling), comes from the Latin caecus, meaning blind: not as in sightless, but as in cul-de-sac. The cecum is an enlarged pouch typically located on the right side of the abdominal cavity and is the first part of large intestine. Both appendix and ileum open into the cecum (Image D).

Cecum and ileum are separated by an ileocecal valve, a slit-like opening in the cecal wall. The valve contains a sphincter of smooth muscle, opening to admit chyme from the ileum, and closing to prevent back flow. Thus, cecum serves as a receptacle for fluid chyme.


Image D

History Detour: Almost simultaneously, the ileocecal valve was described by Dutch physician, Nicholaes Tulp, and by Swiss botanist, Gaspar Bauhin. Depending on which scientist one intends to honor, the iliocecal valve is also either the Tulp valve or the Bauhin valve. Yep, the way the world works!

In case you forgot or haven’t read Anatomy Lesson #34, “The Amazing Saga of Human Anatomy,“ Tulp is the anatomical demonstrator in Rembrandt’s 1632 painting (Image E), “The Anatomy Lesson of Dr. Nicolaes Tulp.” Several modern anatomists have performed dissections trying to recreate the left forearm tendons as depicted in the painting, but to no avail; the painting is anatomically incorrect, which matters ZIP because it is priceless!


Image E

Pretty cool, eh? Now, back to the lesson!

Vermiform Appendix: The appendix is more accurately termed vermiform appendix, cecal appendix, vermix, or vermiform process. Why use one name when four will do, hah! To improve student vocabulary? No, not really. Adding a second word provides specificity because the body has other appendices (pl.) including those associated with ovary, testis, and colon. Thus, vermiform helps verify which appendix is intended.

I prefer the term vermiform appendix. Why? Vermiform is from the Latin vermes meaning “worms” + formes meaning “shape.” Appendix refers to a process or projection. Voila! A normal vermiform appendix is shaped very much like a long, pink worm!

Enough with word roots. Vermiform appendix is a blind-ended, worm-like extension projecting from the cecum and usually located in the lower right abdomen (Image F). It is suspended by a mesoappendix, a fold of mesentery that also provides a conduit for blood vessels and autonomic nerves.


Image F

Appendiceal Location: Illustrations typically place vermiform appendix in the lower right abdominal position, as mentioned above. But, it may assume one of about eight positions relative to the cecum (Image G). Or, a cecum may ride high in the upper right abdominal cavity carrying the vermiform with it, or even shifted to the left side as in situs inversus (Image G). Vermiform appendix may also drift into an inguinal hernia (Image G – red arrow). Interestingly, some alternate appendiceal positions are more prevalent among some populations and cultural groups. Such positional variations can present confusing signs and symptoms and pose diagnostic challenges for practitioners. Truth!

Image G

Function #1: The function of vermiform appendix is unclear. Many anatomists consider it a useless relic of an evolutionary past. But, recent studies suggest it acts as a reservoir for good bacteria. After severe diarrhea, the vermiform appendix apparently “reboots” the large intestine by repopulating it with normal bacterial flora (Image H).

I always taught, and still firmly believe, the body doesn’t have useless organs. I reason that if a body part appears useless, it is our own ignorance that impedes understanding. I must confess, though, one savvy student stumped me with the question: “why do men have nipples?” I had no answer then, but I do now  – subject for another lesson. Understand, the half-life of medical facts is about 5 years, so new and/or revised info emerges daily! Stay tuned! Hee, hee.

Image H

Function #2: Vermiform appendix also serves as a lymphoid organ. Remember the tonsils (Anatomy Lesson #45 “Tremendous Tube” – GI Tract, Part 2) and Peyer’s patches of ileum (Anatomy Lesson #47, “Brave Bowels – Gurgly Gut!” – GI Tract, Part 4)? Moving to a microscopic image, these are aggregates of lymphoid nodules (spheres) containing lymphocytes and other cells functioning in immune responses. Turns out the wall of vermiform appendix is loaded with lymphoid nodules (Image I – blue circles with pale centers) which constantly survey luminal proteins to determine which ones are threatening and require an immune response. Cross my heart!

Now, you may argue that vermiform appendix is of dubious value because many people survive without one. My response: well, people can also live without a leg but that doesn’t mean it isn’t useful! Aye?


Image I

Appendicitis: As we learned in Anatomy Lesson #37, “Outlander Owies Part 3 – Mars and Scars,” any anatomical word bearing the suffix “-itis” means inflammation of…  Thus, appendicitis means inflammation of the appendix, a condition accompanied by swelling, redness, pain, heat, and loss of function.

Book Spoiler #1: The following quote is from Diana’ sixth big book, “A Breath of Snow and Ashes.” You might skip if you haven’t read it, although the quote doesn’t reveal any plot twists. How did prescient Diana know this lesson needed a quote about appendicitis? One of the great mysteries! <G>

The book describes Surgeon Claire treating a young boy with acute appendicitis. I borrow shamelessly from Starz episode 203, Useful Occupations and Deceptions, to illustrate the quote:

I put a thumb in his navel, my little finger on his right hipbone, and pressed his abdomen sharply with my middle finger, wondering for a second as I did so whether McBurney had yet discovered and named this diagnostic spot. Pain in McBurney’s Spot was a specific diagnostic symptom for acute appendicitis. I pressed Aidan’s stomach there, then I released the pressure, he screamed, arched up off the table, and doubled up like a jackknife. A hot appendix for sure. I’d known I’d encounter one sometime…. No doubt about it, and no choice; if the appendix wasn’t removed, it would rupture.

McBurney’s Point: Sounds like a feature of the Scottish coastline <g>, but, its not! McBurney’s Point is the name for a spot on right abdomen that is two-thirds the distance from umbilicus to ASIS, the anterior superior iliac spine of the right hip bone (Anatomy Lesson #39, Anatomy Lesson #39 “Dem Bones – Human Skeleton”). This point roughly corresponds to the most common site where appendix attaches to cecum (Image J). Warning: some descriptions define the point as one-third distance from ASIS to umbilicus. What gives? Going the opposite direction, the latter statement is also true. Do the math!

Try This: Stand before a mirror. Place right fingers over the most prominent bony knob of right hip bone. You know the one – it bumps into corners of tables? Ouch! Now, place right little finger on right ASIS. Place right thumb in navel. Estimate 2/3 distance from thumb to little finger or estimate 1/3 distance from little finger to thumb – this is McBurney’s point! If this is too tough, estimate the halfway point – it will be close. This is likely where the base of your vermiform appendix (if you still have one, of course!) attaches to cecum.


Image J

Back to Appendicitis: And in answer to Claire’s musing, no, McBurney’s point was not described in the 18th century. Who was McBurney? Charles McBurney was an American surgeon who, in 1889, published the relationship between acute appendicitis and McBurney’s point, the typical site of greatest tenderness. Understand, this relationship is not 100% reliable because of appendiceal positional variations and because other abdominal processes may produce tenderness at this site.

Nevertheless, McBurney’s point is significant in three ways:

  • marks the most common site where appendix attaches to cecum.
  • intense tenderness is consistent with acute appendicitis and possible progression toward rupture.
  • most open appendectomies (not by laparoscopy) are performed at McBurney’s point.

Back to Dr. Claire and her spot-on description of anatomy and acute appendicitis!

“All right,” I said out loud, triumphant. “Got you!” Very carefully, I hooked a finger under the curve of the cecum and pulled a section of it up through the wound, the inflamed appendix sticking out from it like an angry fat worm, purple with inflammation. “Ligature.” I had it now. I could see the membrane down the side of the appendix and the blood vessels feeding it. Those had to be tied off first; then I could tie off the appendix itself and cut it away. Difficult only because of the small size, but no real problem … “Forceps.” I pulled the purse-string stitch tight, and taking the forceps, poked the tied-off stump of the appendix neatly up into the cecum. I pressed this firmly back into his belly and took a breath.

BTW, the membrane mentioned in the quote is the mesoappendix but you likely figured that out, already. Image K shows what Aiden’s appendix might have looked like after extraction (sans blue terrycloth).


Image K

Moving on…..

Ascending, Transverse and Descending Colons: Most of the length of large intestine is composed of ascending, transverse and descending colon. These parts can be distinguished easily from small intestine because their diameter is larger and they possess these unique features (Image L):

  • epiploic appendices – fatty globs dangling from the outer surface of colon (even in thin folks)
  • haustra – wall pouches giving the surface a saccular (sack-like) appearance
  • taenia coli – meaning “worms of the colon”, these longitudinal bands of smooth muscle travel the length of the colon (think of them like purse stings holding the wall into haustra)

The mucosa (internal lining) of the colon has no villi, the finger-like extensions riddling the mucosa of small intestine. It does exhibit semilunar folds, transverse folds of mucosa that partially encircle the lumen to increase surface area and support stool (feces). The wall of the colon also contains smooth muscle layers which contract to move stool through the lumen.

Colon Functions:

  • Absorbs water from luminal contents converting them into more solid stool.
  • Saccular design accommodates luminal mass as it solidifies.
  • Houses massive numbers of bacteria which breakdown food matter.
  • Absorbs nutrients from digestion by colonic bacteria and leftovers from small intestine digestion.
  • Releases mucus (protein with attached CHO groups) into the lumen making contents slippery.


Image L

Sigmoid Colon: The sigmoid connects descending colon with rectum. Sigmoid is so named because it is generally S-shaped, although it varies considerably in shape and length! Some of variations are shown in the next two images. Left side of Image M shows a typical sigmoid; right side shows a short, straight sigmoid angling into the pelvis.


Image M

Left side of Image N shows a long sigmoid with a large loop shifted to the right; the right side of the image shows a long sigmoid ascending high into the abdomen. The point is, normal sigmoids assume different shapes, lengths, and positions.

The function of the sigmoid is to accumulate fecal waste until it is ready to leave the body.

This reminds me of a fav saying by surgeons I have worked with: “The good news: there is a light at the end of the tunnel. The bad news: it is a sigmoidoscope!”

Image N

Heeeeeere’s Jamie (Image O) to give you a wee bit of warning! Next up are rectum and anal canal. If these topics cause you discomfort, skip to Jamie and Claire laughing, just before the pelvic floor!

Image O

Rectum: The next organ is rectum, the segment between sigmoid colon and anal canal. At its start, the diameters of sigmoid and rectum are the same, but rectum enlarges as it descends into the pelvis (Image P). Many sources define rectum as extending all the way to the anus, but this is not so; rectum converts to anal canal as it passes through the pelvic floor (Image P – black arrow) and anal canal, being a separate part, ends at the anus.

Rectum has no taenia coli or epiploic appendices and it lies in the pelvic cavity, making it easily distinguished from sigmoid.  Otherwise, its wall contains smooth muscle and a mucosal lining very much like the rest of large intestine.

The rectum serves as a storage receptacle for feces awaiting release via the anal canal. Rectal valves (Image P) are folds of mucosa that help support stool. During elimination, smooth muscle of the rectal wall contracts to aid defecation. And, rectum releases loads of mucus to aid the movement of stool.

Image P

Och! Here is public proof that many mistakenly believe the rectum reaches all the way to the anus; the so-called rectum bar in Vienna (Image Q) is anatomically incorrect. Who on god’s green earth considered this a viable idea? Would you sample refreshment from such an edifice? Snort!

Image Q

Anal Canal:  Last stop! The final segment of large intestine is anal canal (Image R). This complicated structure is pretty short, being only about 1” – 1.5” in length. It begins as rectum traverses the pelvic floor (see below) and ends at the anal verge (anal opening). Its orientation is not vertical, as it is directed downward and backward.

Anal canal is lined with mucosa turning to skin near the anal verge. Its wall contains an internal anal sphincter, smooth muscle over which we exert no voluntary control. Outside the internal sphincter is a sturdy layer of skeletal muscle forming an external anal sphincter, which is controlled voluntarily. Yay!

Normally, both sphincters are tonically contracted but relax during elimination. Psst….a child learns to control the external sphincter during potty training.  In most children, this cannot occur until about 18 months due to nerve immaturity.  A younger child can be taught to alert the parent when defecation is eminent, but he/she cannot voluntarily control the process.


Image R

Here they are, the cuties! Everybody make it through as far as the pelvic floor?

Pelvic Floor: Although not part of large intestine, we must discuss this area because fecal (and urinary) continence requires a healthy pelvic floor. The pelvic floor is formed by the fusion of right and left levator ani muscles forming a muscular diaphragm (we have more than one) that hangs from the bony pelvis much like a hammock (Image S). The floor is pierced by two midline openings in the male, one for urethra and one for anal canal. The female has three midline openings, two the same as a male, plus a middle opening for the vagina (Image S). Each of these openings is supported by levator ani muscles. Although the pelvic floor appears spacious in Image S, in reality it is about the size of half a grapefruit. Very tight squeeze, indeed!

The Way Things Work: A subpart of each levator ani, the puborectalis muscle (Image S) passes backward from each pubic bone to fuse behind the rectum. Forward pull by these paired muscles creates a flexure causing the anal canal to drop downwards and backwards, and thereby closing the channel between rectum and anal canal. During elimination, puborectalis muscles, internal anal sphincter, and external sphincter relax allowing the passage of stool; otherwise, all of these muscles normally remain contracted.


Image S

Blood Supply: Like small intestine, large intestine requires a huge blood supply (Image T). Arteries arise from the aorta and its branches supplying all parts of large intestine, from appendix through anal canal. Major arteries also join to form a marginal artery that follows the contour of the large bowel (Image T). Veins follow similar routes.

This prolific blood supply is used for transport of absorbed nutrients, but also provides a huge oxygen supply because bowels are excruciatingly sensitive to oxygen loss. This is why a twisted bowel, bowel loop caught (incarcerated) in a hernia, or other bowel obstruction is of high concern as such events rob bowels of their blood supply and the accompanying cargo of oxygen –  these conditions present a medical emergency which must be quickly addressed to avoid bowel death! And, yes, bowel obstructions occur in both large and small intestines. BTW, the red arrow of Image T points to the pelvic floor separating rectum from anal canal.

Book Spoiler #2: From Diana’s third book, Voyager, we read about a patient with a strangulated bowel, caught in a hernia. Too late, the bowel is dead, and Claire is none too happy about it. Again, this quote contains no plot twists, so it might be safe for you to read.

The cause of death was more than obvious: a strangulated hernia. The loop of twisted, gangrenous bowel protruded from one side of the belly, the stretched skin over it already tinged with green, though the body itself was still nearly as warm as life. An expression of agony was fixed on the broad features, and the limbs were still contorted, giving an unfortunately accurate witness to just what sort of death it had been. “Why did you wait?”

 

Image T

Book Quote:  Now, let’s apply some of knowledge gleaned from this lesson. Diana’s second big book, Dragonfly in Amber, describes a horrifying scene wherein Mr. Forez describes to Jamie, the disembowelment of criminals! He hopes to dissuade Big Red from engaging in various occupations and deceptions, no matter how useful. As this scene wasn’t included in the Starz episodes, I’ve used a substitute image of the King’s hangman at L’Hôpital des Anges (Starz episode 204, La Dame Blanche)!

“Just there,” he said, almost dreamily. “At the base of the breastbone. And quickly, to the crest of the groin…  —and the letter opener flashed to one side and then the other, quick and delicate as the zigzag flight of a hummingbird—“following the arch of the ribs. You must not cut deeply, for you do not wish to puncture the sac which encloses the entrails. Still, you must get through skin, fat, and muscle, and do it with one stroke. This,” he said with satisfaction… “is artistry.” .. “After that, it is a matter of speed and some dexterity, but if you have been exact in your methods, it will present little difficulty. The entrails are sealed within a membrane, you see, resembling a bag. If you have not severed this by accident, it is a simple matter, needing only a little strength, to force your hands beneath the muscular layer and pull free the entire mass. A quick cut at stomach and anus”—he glanced disparagingly at the letter opener—“and then the entrails may be thrown upon the fire.

Mr. Forez’s description of disembowelment has a few anatomical problems. Scout’s honor. Here’s why:

  • The sac (peritoneum) sealing the entrails also hugs the body wall; once a knife pierces the body wall, too late, that sac has already been severed.
  • Severing skin, fat, muscle and peritoneum in one stroke is nigh to impossible, waaaay too tough! Sawing, maybe!
  • There isn’t a muscle layer under the bag of entrails.
  • A quick cut at stomach isn’t possible as it is covered by greater omentum and transverse colon and tethered by membraneous ligaments. Cannot be reach quickly or severed easily.
  • A quick cut at anus is even less likely because it lies below the pelvic floor – this tough fibro-muscular layer is very hard to access and dissect in such a confined space!
  • If the gut from stomach through anus were removed, the victim would immediately go into shock and rapidly exsanguinate from the severed blood vessels.

Truth: Evisceration was designed to keep a convict alive long enough to ensure maximum suffering! So, typically, a short segment of small bowel was pulled through a belly incision, cut out, and thrown on the fire or given to dogs to eat. Thus, the still living victim could gaze with horror at the fate of his own entrails before finally going into shock from blood loss. Vicious prospect. Who thought this one up????

My conclusion for the boo-boos in Mr. Forez’s gory tale is that first, he is not an anatomist, and, second, he deliberately embellished his gruesome story with horrific inaccuracies to halt Jamie’s seditious activities. Of course, this threat didn’t work! Jamie is one stubborn Scot, aye?

So, we now know the structure and functions of the large intestine. Let’s take a few moments to discuss what happens inside the dark tube.

Good Bacteria: We generally think of bacteria as being bad, but in a normal gut, most are good (Image U). Although stomach and small intestine contain relative few species of bacteria, numbers in the large intestine are staggering! More than 1,000 different species of bacteria inhabit the normal large intestine, collectively, that’s trillions of bacteria! Here’s an astonishing factoid: dried feces is 60% bacteria. Yowser!


Image U

Microbiota: Gut flora, collectively known as the microbiota, is a complex community of organisms living mostly in large intestine. Interestingly, our gut flora is established by one to two years of age. Because the gut and its bacteria co-developed, our gut becomes tolerant to, and even supportive of, gut flora. These organisms aren’t just commensal, they are mutualistic, meaning both they and we benefit. Here is what they do for us:

  • Ferment dietary fiber (cellulose) into molecules which we can absorb.
  • Synthesize Vitamins B and K.
  • Probably act as an endocrine organ.
  • May protect against inflammatory and autoimmune conditions.
  • Fill ecological niches that that might otherwise be subject to hostile takeover by pathogenic organisms.

Image V presents a marvelous visual of gut bacteria, a scanning electron micrograph (SEM). It would be great fun if gut bacteria really did come in such marvelous colors, but, no, these are computer generated. The woody-looking slab isn’t for the fireplace; it is a wee shard of dietary fiber!


Image V, SEM by Martin Oeggerli

Western Diet: Now, we could get embroiled in a messy discussion about diet as there is a gut-full of claims floating around in the ethernet. I don’t mean to be a harpist about the western diet (Image W), but 90% of Americans do not know there is a link between diet and cancer!

To the point: Colorectal cancer (bowel cancer) is the second highest cause of cancer deaths, both in the US and in Great Britain!  Americans are 13 times more likely to develop bowel cancer than Africans. Thus, in a recent scholarly study, 30 healthy Africans were fed an American diet (high fat, low fiber) and 30 Americans ate an African diet (high fiber, low fat). After two weeks, two weeks I say!, all subjects received a colonoscopy and various tests. Americans on the African diet experienced decreased inflammation and increased production of a fatty acid proven to protect against colon cancer. Africans on the American diet showed increased inflammation and changes that precede the development of cancerous colon cells. This short term study underscores the speed with which an adverse relationship between poor diet and poor colonic health may develop.

Hopefully, you all realize that dietary fiber (roughage) is needed for the large intestine to do it’s job (hee, hee). Fiber helps prevent “traffic jams!” Eating lots of whole grains, legumes, fruits, and veggies aids elimination. Too little dietary fiber coupled with too much fat is a fine recipe for “road blocks!”


Image W

Now, time for some potty talk! Outlander provides, as always…Yep, Diana’s books contain a number of references to beautiful bowels and their dubious duties (Dragonfly in Amber book).

“A verra wearisome business it was, too,” he added, bending over and setting his hands on the floor to stretch the muscles of his legs.

What is wearisome, and whom is Jamie discussing? Why, King Louis of France, of course (Starz episode 202, Not in Scotland Anymore). Annalise de Marillac does Jamie the dubious honor of hustling him off to observe King Louis perform his morning “rituals”  – Murtagh follows, at Claire’s command! The puir man must poop before the entire world. Imagine!

Prof. Jamie explains further in Dragonfly in Amber book:

Took forever; the man’s tight as an owl.” “Tight as an owl?” I asked, amused at the simile. “Constipated, do you mean?” “Aye, costive. And no wonder, the things they eat at Court,” he added censoriously, stretching backward. “Terrible diet, all cream and butter. He should eat parritch every morning for breakfast—that’d take care of it. Verra good for the bowels, ye ken.

This puir King was famously costive because his fat-rich/low-fiber diet resulted in chronic constipation. And, constant straining can balloon the walls of veins draining the anal canal, resulting in hemorrhoids (Starz episode 202, Not in Scotland Anymore). Truth be told, Lionel Lingelser is one fearless thespian! Hope he was well-paid for this scene; check out the rivulets of sweat streaking his forehead. Oooooh, straining!

Our two “gently-bred” Scots are frankly appalled but they observe the theatrics with manly composure leading Jamie to prescribe peasant parritch for breakfast each morn (Starz episode 202, Not in Scotland Anymore)!

Who do you think has the worst job? King Louis who must master his bowels before the known universe, or the court physician who must verify his success – or lack thereof (Starz episode 202, Not in Scotland Anymore)? Hard to say, hah!

Thus “ends” the saga of the GI Tract from lips through anus –  it took 5 lessons to cover this tremendous tube!

Let’s close this lesson with a few jokes about large intestine and its duties…. dumb but not too offensive, I hope!

  • Have you seen that new movie, Constipated? … It’s not come out yet!
  • Have you seen its sequel, Diarrhea? … It leaked, so they had to release it early!
  • Did you know that diarrhea is hereditary? … It runs in your genes!
  • I ate four cans of alphabet soup yesterday. Then I had the biggest vowel movement ever!
  • People who tell you that they are constipated are full of crap. <G>

The body is sooo cool! Thus ends the fascinating tale of our large intestine, “The big Guy!” Next lesson, liver and its cohorts!

A deeply grateful,

Outlander Anatomist

Karmen L. Schmidt, Ph.D.

PIcture creds: Starz, Atlas of Human Anatomy, Frank H. Netter, M.D., 4th ed. (Images C, D, E, F, G, I, L, M, N, S, T), Medicine Perspectives in History and Art, Robert E. Greenspan, M.D., 2006 (Image E), www.care2.com (Image O), www.enwiki.org (Image H; Image S), www.findchart.com (Image B). www.icanrunaminute.com (Image J), www.lydiaskindfoods.com (Image W), www.mayoclinic.org (Image R), www.medicalnewstoday.com (Image A), www.motherjones.com (Image U), www.ngm.nationalgeographic.com (Image V), www.researchgate.net (Image K), www.sites.google.com (Image P), www.walyou.com (image Q)

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Anatomy Lesson #46: “Splendid Stomach, Wobbly Wame” – GI Tract Part 3

Hey, anatomy students! Great to see you again. Today’s lesson slides further along the GI tract’s slippery slope, as we visit the stomach. The stomach goes by a mess of nicknames: abdomen, beer belly, belly, breadbasket, girth, gut, guts, insides, middle, paunch, pot, potbelly, spare tire, tummy, and Jamie’s fav, the wame! Most of these terms actually refer to the anterior abdominal wall (Anatomy Lesson #16, “Jamie’s Belly” or “Scottish Six-Pack”), a cause of anguish for many of us (Image A). But, for anatomists, stomach or gaster (Greek gastēr meaning stomach) specifies an organ of the GI tract.

The stomach is absolutely fascinating and near and dear to my heart as in the 80’s and 90’s it was the focus of my research; during that time, I published 100+ papers, abstracts, and invited lecturers in far flung places such as Holland and Japan. Although a few papers ventured into realms of liver and colon, most focussed on stomach. So, let’s have a meet-and-greet with the stupendous stomach. Outlander images included for free (psst, they are near lesson’s end)!

Image A

Stomach: The stomach is a hollow, dilated, comma-shaped organ of the GI tract, dwelling between esophagus (Anatomy Lesson #45, “GI System – Part 2”) and duodenum (first part of small intestine). Tucked under the respiratory diaphragm, it sits in the upper left abdominal cavity (Image B).

Image B

Stomach Relationships: Centrally placed, the stomach contacts many other organs, a fact relevant to the spread of some cancers. These organs are:

Understand that due to embryology, the stomach lies on it’s side (Image C) exposing two curves: the lesser curvature faces to our right and the greater curvature faces to our left.

Image C

Stomach Mesenteries: The stomach doesn’t drift in the abdominal cavity, rather, it is anchored by mesenteries, double layers of peritoneum, a membrane lining the abdominal cavity and covering most of its organs (Image D). Mesenteries are challenging to explain without a lesson of gut embryology, but, such structures suspend stomach from spleen, diaphragm, colon, and liver.

The lesser omentum (obscure Latin origin) is a mesentery connecting lesser curvature of stomach with liver.

The larger, greater omentum hangs from the greater curvature of the stomach, draping over the intestines much like an apron. It is the first structure encountered when the abdominal cavity is opened via anterior incision. The greater omentum serves as a storage depot containing various amounts of adipose (fat) tissue. It also houses pockets of macrophages, a type of white cell that ingests debris, foreign material, microbes, etc. Amazingly, the greater omentum also wraps around and isolates areas of infection, foreign bodies, or trauma, walling them off from other abdominal organs!

Image D

Stomach Capacity: The stomach is a hollow bag which expands to accommodate a meal. The gastric capacity changes from the size of a strawberry in newborns to the size of a small cantaloupe in adults (Image E). Thus, a normal adult stomach has the capacity of about 1 liter (1+ qt.). Once an adult, stomach capacity stays pretty constant. If we stuff ourselves during the holidays, It can expand to 5x its normal size, but it returns to its former size once the food has gone bye-bye. The Internet is filled with claims about dieting, purging, stuffing, stomach size, etc. Here are a few myths about the stomach:

Stomach Myth #1: Eating less food shrinks the stomach. It doesn’t. Eating less won’t shrink the stomach, but it does reset the hunger thermostat (in the brain) so we don’t crave as much food to feel full.

Stomach Myth #2: Skinny people have smaller stomachs than heavier people. They don’t. A person’s weight doesn’t determine stomach size.

Stomach Myth #3: Dieting shrinks the stomach. It doesn’t. An adult stomach remains the same size although dieting can rid one of belly fat both internally and under the belly skin.

Image E

Stomach Parts: Anatomists could not leave well enough alone, sigh, they had to divide the stomach into regions (Image F). Why? Because they have anatomical and physiological differences:

  • cardia (green), region adjoining the esophagus
  • fundus (red), upper curvature of stomach. From the Latin meaning bottom – go figure!
  • body (dark pink) main, middle part of stomach
  • pyloric antrum (purple) is the lower part of the stomach
  • pyloric canal (blue) tubular area of stomach which empties into the duodenum (orange).
  • pyoric sphincter terminal valve leading into duodenum (labelled pylorus)

Image F

Now, let’s examine the thick stomach wall, endowed with muscle and mucosa (and other stuff that you won’t find compelling so we’ll skip them).

Stomach Muscle: The stomach wall is thickened with layers of smooth muscle. You remember smooth muscle from Anatomy Lesson #45? This type lacks cross striations and is under autonomic (involuntary) control.

The stomach wall is endowed with three thick layers of smooth muscle oriented in different axes. The outer longitudinal layer of smooth muscle is oriented with the long axis of the stomach. A middle layer of smooth muscle encircles the lumen (Image G).

Image G

An innermost oblique smooth muscle layer is oriented at angles to both longitudinal and circular layers. At the pylorus, the circular layer thickens markedly to form the pyloric sphincter, which contracts to retain gastric contents or relaxes to allow the contents to enter the duodenum (Image H).

Such muscle layers aren’t just another pretty face; in fact, contraction of these layers serve a very important function, discuss below.

Image H

Gastric Rugae: Opening the stomach along its long axis reveals the lumen (central space) and lining mucosa. Last lesson, we learned the mucosa is a layer of living cells lining  a lumen. Internally, the landscape is not smooth, rather it is thrown into numerous rugae, folds of the gastric mucosa (Image I).

The purpose of rugae are two fold: they stretch outward and flatten, allowing the stomach to expand and accommodate food and drink and they increase surface area for absorption. Note the zig-zag (Z) line marking the gastroesophageal junction at the gastric entrance – we learned about it in the last lesson (Anatomy Lesson #45, “Tremendous Tube – GI System, Part 2”). The pyloris marks the far end of the stomach – more about it soon.

Image I

Gastric Pits: If you stand inside your gastric lumen (not recommended, <G>), you certainly will see the rugae. But, let’s say you zoom in and view the mucosal surface using a scanning electron microscope (SEM) (Anatomy Lesson #34, “The Amazing Saga of Human Anatomy”); you would behold an amazing site-sight! The entire surface of the gastric mucosa is dimpled with holes known as gastric pits (Image J – green arrow). Gastric pits plunge down into the mucosa much like open water wells into the ground.

Surface mucosal cells (bumps) surround the holes. When stimulated, these cells produce mucus and bicarbonate (think baking soda). BTW, the orange color is computer generated, not natural.

Image J – Photo by Steve Gschmeissner gastric pits

Gastric glands: One or more gastric glands open into the base of each pit, so glandular secretions flow up the gastric pits and into the gastric lumen. The stomach has millions of pits and multimillions of glands. Got it? Swell! Now, these glands contain different cell populations depending on their location. Thus, the fundus and body contain gastric glands; the pylorus contains pyloric glands (Image K). Oh, and dinna worry about all the layers listed in Image K; these are for folks taking histology/microscopic anatomy courses.

Image K

Now, don’t let Image L scare you away just because it shows a little physiology (lower right)! Hang on and let me explain….. upper left of the image is an SEM of the mouth of a single gastric pit. The bumps surrounding it are surface mucosal cells. Below it is a diagram showing two gastric glands opening into the base of one gastric pit; let’s focus on this part of the diagram.

Gastric glands contain several different cell types. One type (mucous cell) produces mucus, another type (chief cell) produces pepsinogen/pepsin, a protein-cleaving enzyme, and lipase, an enzyme that metabolizes fats. Gastric glands also contain APUD cells (not labelled) which produce several hormone-like substances controlling stomach, gallbladder and small intestine activity. And, then, we have the parietal cell – ta da!

Image L

Parietal Cell: Parietal cells are powerful, period! They deserve super special recognition because they produce hydrochloric acid (HCl), a gastric acid of pH ∼1.5 (pH measures acidity or alkalinity) – almost as acidic as battery acid! This harrowing stuff is necessary to denature (unravel) dietary proteins so they can be digested. It also destroys microbes in our food and drink. Even with a clean kitchen, our food is loaded with bacteria. Scrub brush, STAT!

Here’s a quickie of how parietal cells produce HCl. Each cell can change its shape as shown in Image M, a split drawing. When a parietal cell is resting (Image M – bottom half of cell), it has a tiny inlet (labelled IC) extending a short way into the cell. When parietal cells are stimulated (image M – top half of cell), the inlet or bay (intracellular canaliculus) expands dramatically and HCl ions (components) are pumped across the cell membrane and into the IC; they flow up the gastric pit and into the gastric lumen.

Needing more to do, pariental cells also produce intrinsic factor (IF), a glycoprotein required to absorb Vitamin B12. One may consume all the B12 in the world, but none can be absorbed without intrinsic factor. Lacking intrinsic factor and B12, our brains and nervous systems function poorly and we cannot form normal red blood cells (Anatomy Lesson #37, “Outlander Owies Part 3 – Mars and Scars”). So, take a big bow, parietal cell – we thank ye kindly!

In summary, parietal, mucous, APUD and chief cells generated fluids that pour into the gastric lumen after food is received from the esophagus. The powerful muscular wall then contracts in waves mixing food and fluids into a watery mass known as chyme.

Image M

Gastric Mucosal Barrier: Now, being curious anatomy students, you must wonder how the stomach withstands gastric juices nearly as caustic as battery acid??? Of course, you do! Well, it is complex. Decades ago, this protective feature was termed the gastric mucosal barrier (GMB), although no one knew exactly what it was.

After more than 30 years of effort and millions of research dollars, it appears that the GMB isn’t one protective mechanism, it is at least three: tight junctions, mucus, and bicarbonate!

  • Tight Junctions: Surface mucosal cells are “joined at the hip” by tight junctions; unions so tight, they exclude harsh gastric fluids.
  • Mucus: A layer of insoluble mucus tenaciously clings to the surface mucosal cells forming a barrier against auto-digestion by pepsin and erosion by HCl.
  • Bicarbonate: When parietal cells release HCl, surface mucosal cells release a tide of bicarbonate (think baking soda, again) to neutralize nearby gastric acid.

These three factors conspire to bring the pH near the surface mucosal cells to 7 or neutral…neither acidic or alkaline (Image N)!

  • Layer A is gastric acid, pH 1.5. Über caustic!
  • Layer B is insoluble mucus and bicarbonate (HCO3-) released by surface mucosal cells (pH 2-7)
  • Layer C is the union of tight junctions (see circle – very tiny) joining surface mucosal cells (pH 7)
  • Layer D is the surface mucosal cell layer

(p.s. Let’s ignore layers E and F)

Ergo, the stomach creates a harsh luminal environment and the GMB protects the stomach from its own offspring!

Image N

Historical Tidbit: A hundred years before Jamie’s time, European scientists argued about the purpose of the human stomach. Some claimed the it was a stove wherein food literally burned. Others sided with Galen, declaring it a storehouse that sorted wheat from chaff. Still others posited the stomach was a fermentation vat. BTW, the vat idea wasn’t confined to Europe as it also appears in 19th century Japanee wood blocks prints. Image O shows the artist’s concept of a good diet. A vat representing the stomach complete with attendants appears in the upper left abdominal quadrant. So, whose argument was correct?

Image O by Inshoku Yōjō, Kagami Kabuki wood blocks

This who’s “right – fight” continued for another century until John Hunter arrived on the scene (Anatomy Lesson #3, “Bad Day at Cocknammon Rock” or “Wee Bonny Fingers on my Collar Bone!”). Diana wrote about Hunter in her 7th book (Image P) – hope you read it! Dr. Hunter (1728-1793) aptly responded to the debate: “Some physiologists will have it that the stomach is a mill, others that it is a fermenting vat, but a stomach, gentlemen, is a stomach.“ Reminds me of Sigmund Freud’s supposed comment about his omnipresent “sexualized” cigar: “Gentlemen, sometimes a cigar is just a cigar!”

Image P Oil painting after Sir Joshua Reynolds.

Now, onto the pylorus.

Pylorus: (How to pronounce this word? Pylorus rhymes with Delores. Har, har! (Those who follow Diana may get this wee joke.) Pylorus is a Greek word meaning gatekeeper. Why the name? Because the pyloric sphincter opens in controlled waves allowing small “gulps” of chyme into the duodenum. Too much chyme, too quickly, and one is greeted with nausea, vomiting, cramping, bloating, and diarrhea! This activity is highly controlled.

“Control?,” mutters a befuddled Murtaugh, who has been in the anatomy lab with French maid, Suzette (Starz episode 203, Useful Deceptions and Occupations)? Ha, ha! Not birth control, Murty – nerve control!

In a nutshell, we now know the splendid stomach gives us the follow splendid gifts:

  • Acid: secrets HCl to denature ingested proteins and kill bacteria.
  • Pepsin and lipase: releases enzymes to digest proteins and fats.
  • Churn: smooth muscle layers contract in waves to mix food, mucus and HCl into watery chyme.
  • Hormones: secretes six hormone-like substances controlling stomach, small intestine, and gallbladder.
  • Informant: senses carbohydrates, proteins, and fats and informs the brain to evaluate food palatability and link nutritional value with taste.
  • Storage: stores chyme until hormones and nerves signal the pyloric sphincter to relax.
  • Absorption: takes up water, aspirin, ethanol, caffeine, water soluble vitamins and alcohol, etc.!

Alcohol: Speaking of alcohol, the gastric mucosa (and liver) contains alcohol dehydrogenase, an enzyme which detoxifies alcohol at the rate of roughly one stiff drink per hour. On average, men have more of this enzyme than women and, thus, can metabolize alcohol more effectively. Sorry gals, this isn’t sexist, it is nature! (Take comfort, there are things gals do better than guys). Looks like mighty fine wine (Starz, episode 204, La Dame Blanche). You,  Jamie, not the drink. Snort!

Alcohol: Because the stomach absorbs alcohol, this is an apropos spot to insert the topic of alcohol and pregnancy. Some fans have asked about Claire’s drinking alcohol while pregnant with Faith (Starz episode 204, La Dame Blanche). Today, we are well aware that pregnant women must avoid the perils of alcohol, but given the time and place of Outlander S.2, drinking by pregnant women would have been prevalent. Fetal alcohol syndrome even wasn’t described until 1973, well after Claire’s pregnancies, so even as a battle-trained nurse, she would have been unaware of it’s detrimental effects. Thanks production team for staying true to the times depicted. Go Outlander team. Rah!

Now, does the knowledge that alcohol ingestion can adversely effect a pregnancy stop some women from imbibing? Consider a statement by Brit Henry Youngman: “When I read about the dangers of drinking, I gave up reading.” Human logic can take one to very odd places!

Vomiting: Gah, even the word sounds ominous! This awful bodily reaction occurs as the stomach seeks to purge itself of noxious stuff. Vomiting goes by many names: ralph (where did that name come from?), heave, upchuck, spew, gag, be sick, retch, barf (my fav), puke, throw up, regurgitate, emit, and disgorge!

Vomiting comes in two phases. First, during the retching phase, abdominal, thoracic, and diaphragmatic muscles undergo convulsive contractions (you know the drill) but nothing is expelled. Second, during the expulsion phase, retrograde peristalsis starts in the small intestine and sweeps upwards. Pyloric and lower esophageal sphincters relax. Thoracic and abdominal muscles contract to increased intra-thoracic and intra-abdominal pressures which propel gastric contents upwards to explode all over Aunt Jocasta’s Isfahan carpet! Mop, STAT!

Retching is preceded by feelings of nausea and increased salivation, deep breaths, sweating, and increased heart rate. You ken, right? These responses are helpful as salivation helps protect tooth enamel from stomach acids (very corrosive). The deep breath helps prevent aspirating vomit into the larynx. Sweating and increased heart rate are autonomic responses to stress.

No Persian carpet at the abbey, but Claire feels nauseous for sure (Starz episode 116, To Ransom A Man’s Soul)! Her look of distress, a sheen of sweat, plus the belly grip is a sure signal that her wame is wobbly. Of course, Murtagh and the Monk (good book title? <g>) haven’t a clue that the lass is pregnant – they think she swoons because beloved Jamie lies depressed, damaged, and despairing! Well, that, too.

Now, nausea and vomiting are common among pregnant women. Only about 30% of expectant moms are spared either or both. But, Claire isn’t one of the lucky ones. Her’s is a willful, wobbly wame. She barely gets Jamie’s hand repaired before losing her parritch behind a colum, oops, column, in the abbey corridor (Starz episode 116, To Ransom A Man’s Soul). I know, I know, it’s a lame joke, but we must keep spirits up while we wait, wait, and WAIT for S.3!

Even after arriving in Paris, Claire continues upchucking. Herself explains, from Dragonfly in Amber book:

“No. I’m quite all right now.” And I was. In the odd way of morning sickness, once the inexorable nausea had had its way with me, I felt perfectly fine within a moment or two. “Let me just rinse my mouth.”

…“Sassenach, you’re with child! Ye dinna mean to go out to nurse beggars and criminals?” … I pressed my hands against my belly, squinting down. “It isn’t really noticeable yet; with a loose gown I can get away with it for a time. And there’s nothing wrong with me except the morning sickness; no reason why I shouldn’t work for some months yet.”

…“Feeling all right, are ye, Sassenach? The sickness is better?” “Much.” The morning sickness had in fact abated, though waves of nausea still assailed me at odd moments.

Claire’s vomiting at the abbey had au naturale causes. But, in Paris, poison is the culprit! Well, truth be told, Comte St. Germain is the blackguard as he conspires to poison her drink (Starz, episode 204, La Dame Blanche). Gloating, he doesn’t give a fig about her or her unborn child. Let them eat cake!

Next day, Claire hikes up to Master Raymond’s apothecary (Starz, episode 204, La Dame Blanche): “I was violently ill last night. Someone tried to kill me. I almost died!”

But, the Master kindly informs his fav madonna: “The effect is most immediate… The stomach seeks to purge itself and, well, you get the idea.” The Master sells bitter cascara to clients (think Comte servant) who in a moment of passion, seek to poison their enemy. But, while the enemy visibly suffers (to the satisfaction of the poisoner), it doesn’t kill them (to the satisfaction of the poisoned).

Diana offers more insight, from Dragonfly in Amber book:

“Poison for a rival,” he said. “Or at least she thinks so.” “Oh?” I said. “And what is it really? Bitter cascara?” He looked at me in pleased surprise. “You’re very good at this,” he said. “A natural talent, or were you taught? Well, no matter.” He waved a broad palm, dismissing the matter. “Yes, that’s right, cascara. The rival will fall sick tomorrow, suffer visibly in order to satisfy the Vicomtesse’s desire for revenge and convince her that her purchase was a good one, and then she will recover, with no permanent harm done, and the Vicomtesse will attribute the recovery to the intervention of the priest or a counterspell done by a sorcerer employed by the victim.”

Just so you know, bitter cascara was a folk medicine historically used as a laxative by native Americans and American immigrants. The plant was not identified by scientists until the 1800s, although its European counterpart (European buckthorn) appeared in a 17th century London Pharmacopoeia. Today, it is unavailable in US laxatives because of harmful side effects including intestinal pain, severe diarrhea with dehydration, and abortive action. That is to say…. avoid!

Stomach Diseases: At least 11 diseases commonly plague the stomach. Since we cannot cover all, let’s “talk” about ghastly gastric ulcers.

For decades, doctors thought stress, spicy foods, smoking, or other lifestyle habits caused peptic ulcers. But, in 1982, two Australian physicians, Drs. Marshall and Warren, reported a link between Helicobacter pylori and gastritis/gastric ulcers (for which each received a Nobel Prize!). Many in the medical community found the report heretical as it was believed no bacterium could survive the acidic gastric environment. Facing steep criticism, Dr. Marshall courageously drank a culture of H. pylori and within three days developed gastritis. Yep, cause and effect. Surprised by his dedication? Think Claire – tasting urine for sugar content at L’Hôpital des Anges!

Helicobacter Pylori:

H. pylori is shaped like a corkscrew with flagella (motile tails). Burrowing through the mucous layer, it creates ammonia which damages and destroys surface mucosal cells (Image Q). The hole in the mucous layer also allows luminal HCl to contact surface mucosal cells, adding to the damage and leading to gastritis and/or ulcers (talk about biting the hand that feeds you!). Ulcers are serious complications as they can bleed, cause infection, or even block the passage of food in the digestive tract. Not good!

Hard to believe, but world-wide, 50% of all humans carry H. pyloris! For unknown reasons, most carriers are asymptomatic and infections are treatable with antibiotics. Whew!

Image Q

Let’s end this anatomy lesson with another splendid stomach story from an earlier era! In 1822, William Beaumont, a 27 y.o. surgeon in the U.S. Army, was stationed at Ft. MacKinac, Michigan. One fine day, Alexis St. Martin, an employee of the American Fur Company, was brought to his surgery. Martin had been shot in the back by accidental discharge from a musket less than a yard away. Yep, shooting accidents happened well before our time!

The wound was the size of a man’s hand and included fractured ribs, lacerated diaphragm, torn left lung, and a perforated stomach! The dirty wound contained remnants of musket discharge, pieces of clothing, and shards of rib, all of which were driven into the chest cavity. The exit wound, under the left breast, included some stomach extruding the remnants of a recent meal. Och! Dr. Beaumont pushed lung and stomach back into proper position and treated the wound with a fermenting poultice, ammonia, and vinegar followed with oral aqueous camphor. The next day, he bled Alexis (unfortunate, but true to the times), and gave an oral cathartic which promptly “escaped from the stomach through the wound.”

Dr. Beaumont fully expected Alexis to die. This did not happen, but something amazing did! Alexis’ wound healed (sans antibiotics) leaving a fistula (abnormal connection) between the stomach and his skin (Image R). Understand that Alexis had a strong constitution and lived to be 60 y.o.! A drawing of his healed wound appears in Image R.

Image R

Alexis’ wound produced a “window” into the gastric lumen. Now, very little was known about the stomach at that time, so Beaumont launched a series of gastric experiments (1825 -1833). During this time, Dr. Bill devised clever experiments wherein he observed changes of the gastric mucosa during fasting, eating, and drinking. He tied string to chunks of food and lower them through the fistula. He then observed and recorded changes in the stomach as it responded to each morsel. He also tapped gastric juice and described its activities outside the body (Image S) and he recorded the effects of various alcohols on the gastric mucosa.

Image S

Dr. Beaumont meticulously recorded his observations over the next eight years! Then in 1833, with his own funds, and never having published before, he published his own book: “Experiments and Observations on the Gastric Juice and the Physiology of Digestion” (Image T). To this day, his observations and conclusions have not been refuted (amazing!). His reward for this effort? Today, he is known as the “Father of gastric physiology.” But, one of the most amazing details of this story… Dr. Beaumont never went to medical school (he apprenticed)!

Speaking of observations and conclusions: Claire would have respected Dr. Beaumont’s devotion to the scientific method unlike her withering opinion of Gillian Edgar’s (Geillis Duncan) “scientific method.” Here, from Dragonfly in Amber book:

In a parody of the scientific method, the first section of the book was titled “Observations.” It contained disjointed references, tidy drawings, and carefully numbered tables.

And below, the notebook filled with fine cursive script, laying out in strict order conclusion and delusion, mingling myth and science, drawing from learned men and legends, all of it based on the power of dreams. To any casual observer, it could be either a muddle of half-thought-out nonsense or, at best, the outline for a clever-silly novel. Only to me did it have the look of a careful, deliberate plan.

The central section of the notebook was titled “Speculations.” That was accurate, at least, I reflected wryly.

Back to Beaumont and St. Martin! I am honored to own a facsimile of Dr. Beaumont’s book, one of the most prized in my anatomy library. I hope you can muster a bit of awe for this accomplishment. Today, such experiments would be deemed unethical, but remember the times – this helps me keep such events in perspective.

 

Image T

Woo hoo, prof! The bell has rung and time to stop. We ken ye adore the stomach, but do bring this lesson to a close. It’s almost Christmas Eve! Hee, hee.

”The stomach is lowest and has a hidden place in the body because of its uncleanness, as though nature had spared the principal members and had relegated the stomach or bowels farther away from the site of reason and of the mind and fenced it off with the diaphragm in order not to disturb the rational part of the mind with its importunity.  These members serve the higher ones.  Some of them concoct the food into juice, others digest it into various humors, others expel the superfluity.” — Alessandro Benedetti, 1497

WRONG! I once worked with a pair of colleagues who shared Alessandro’s opinion, mocking the stomach as lowly and insignificant. Over the years, attitudes have shifted to those of considerable respect for the superb, spectacular, sumptuous, sublime and splendid stomach. It has “convos” with the brain, folks! <G>

Now, as Starz hasn’t graced us with an image of the anatomical stomach, will this one do (Starz, episode 204, La Dame Blanche)?  Snort! Hike that sark up a wee bit more, Jamie, no a better wame anywhere. Double snort!

“Up on the housetop reindeer paws…..” Santa? Naw, it’s just the Bonny One with a nasty monkey bite. Hah!

 

Happy holidays to all and to all a good night!

A deeply grateful,

Outlander Anatomist

Photo creds: Starz, Netter’ Atlas of Human Anatomy, 4th ed. (Images C, D, G, H, I), Beaumont, William, M.D. “Experiments and Observations on the Gastric Juice and the Physiology of Digestion,”Oxford Historical Books, Abingdon, 1989 (Images R, S, T), www.cancer.gov (Image B – overview of stomach in abdomen), www.commons.wikimedia.org & Wellcome Library, London (Image P – John Hunter), www.enwikipedia.org (Image F – stomach parts; Images N – GMB; Q – H. pylori), www.fineartamerica.com (Image J – SEM), www.healthyfoodstyle.com (Image A – gastric shapes), www.histonano.com (Image M – parietal cell resting vs active), www.hyperallergenic.com (Image O – Kabuki actors), www.meritnation.com (Image K gastric glands a), www.slideshare.net (Image L – gastric glands b), www.thevisualmd.com (Image E – stomach volume)