Errors in First Aid for the USMLE (2007): Gastrointestinal System

As always … corrections, suggestions and additions are welcome in the comments.

Gastrointestinal

  1. P.280, Abdominal layers
    1. Not necessary, but I’m just begging you to change this image. In contrast to a typical cross-section on CT, this image is flipped over its axis. This means that with left body on right page, we are looking from head-to-toe and not toe-to-head (as in a CT) and the anterior abdominal wall is placed below the spine on the page instead of above (as in a CT). The simplest solution is to remove all the labels, flip the image across its horizontal axis (as opposed to rotation which would place the IVC and Aorta incorrectly), and then reapply the labels.
  2. P.281, Femoral triangle
    1. The Femoral nerve is not labeled correctly as a nerve. Instead, the “Femoral a.” and “Femoral v.” labels are both pointing to the Femoral nerve. The Femoral artery and Femoral vein are not labeled. This image is also missing the “Empty space and lymphatics” of the femoral triangle.
  3. P.282, Inguinal canal
    1. The “Deep inguinal ring” label is not labeling anything. I think a bar pointing to the ring should be added.
    2. The label “Medial umbilical ligaments” is pointing to one (of two) of the medial umbilical ligaments and (incorrectly) to the median umbilical ligament. The labeling should change appropriately.
    3. The labels “Deep inguinal ring” and “External inguinal ring” are not consistent with the next page, and I think the small changes to “Internal (deep) inguinal ring” and External (superficial) Inguinal ring” would clear up any confusion and bring it in line with the descriptions on the following page.
  4. P.284, Salivary secretion
    1. I think a fourth bullet point with “Lingual lipase begins TAG digestion; activated at low pH on reaching stomach” should be added. This offers a contrast to the activation and action of alpha-amylase.
  5. P.285, GI hormones
    1. I think it’s worth mentioning that Gastrin’s effects are inhibited by Somatostatin. According to Costanzo (BRS Phys), it is a pH of 3 (not 1.5 ) which is the checkpoint for the gastrin/acid-secretion feedback loop between the antrum and the body of the stomach.
      1. Vagal stimulation of gastric acid secretion is due to ACh (as listed on P.284), but no mention is made that vagal stimulation of gastrin secretion from G cells is due to Gastrin Releasing Peptide (GRP). Because this explains why anti-muscarinics do not prevent the secretion of gastrin, I think it should be mentioned.
    2. Cholecystokinin should include “(CCK)” since this abbreviation is not stated elsewhere and is used within the same row of the table. It is also worth mentioning that CCK potentiates Secretin’s effect on pancreatic HCO3- secretion.
    3. Secretin’s effect on increased bile production is not mentioned.
    4. I think it’s worth adding the second-messenger systems used by each hormone. Since Gs, Gi and Gq were previously covered (P.214) I think it’s helpful enough to list the following next to each hormone:
      1. Gastrin (Gq)
      2. CCK (Gq)
      3. Secretin (Gs)
      4. Somatostatin (Gi)
      5. GIP (Gs)
      6. VIP (Gs)
      7. NO (cGMP)
  6. P.286, Regulation of gastric acid secretion
    1. The pattern established by this figure is that each drug with a line towards a receptor is inhibitory for that receptor. This is not the case for Misoprostol, which is a PG analog and stimulatory at the receptor. To avoid any confusion, I think that + and – signs are more appropriate here.
  7. P.294, Alcoholic hepatitis
    1. Changing the mnemonic from “You’re toASTed with alcoholic hepatitis” to “ToASTed, Sam GOT alcoholic hepatitis” helps you remember that SGOT is also known as AST (which is easy to forget).
  8. P.296, Primary sclerosing cholangitis
    1. I had no idea what an ERCP was, nor would I expect most other second-years to know it. If it’s going to be mentioned, I think it should be spelled out to “endoscopic retrograde cholangiopancreatogram (ERCP)”
  9. P.296, Reye’s syndrome
    1. In the way that acute pancreatitis is associated with gallstones and ethanol (for example), Reye’s is not associated “with viral infection … and salicyclates;” it is associated with the combination. It’s subtle but important. I think “and” should be changed to “treated with“.

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17 Responses to Errors in First Aid for the USMLE (2007): Gastrointestinal System

  1. Theo says:

    nr 4, p 284. Our lecturer said that some books bring up lingual lipase, but said something about how it is relevant in mice but not to that extent in humans? And to a low percentage?

  2. karen says:

    p.295 diagram…I’m not positive, but it seems like the Gilbert Syndrome arrow should be pointing to the same site (enzyme) as the Crigler-Najjar Syndrome arrow. If not, please correct me…

  3. karen says:

    p295 diagram…so, BRS Physiology says Gilbert Syndrome includes both the decreased uptake of bilirubin into the hepatocyte and reduced activity of glucuronyl transferase. So, arrows could point to both sites in the diagram.

  4. darren says:

    p. 279: frequencies of basal electric rhythm: says “Hz” (i.e. per second), should say “per minute”

  5. Nelson says:

    Darren–that is exactly right! Great catch. I was wondering why I didn’t “feel the bass” of the slow waves of peristalsis…

  6. Nelson says:

    p293 (in the word document, not posted here) – I don’t think the ascending colon is the most common site for colon cancer. Goljan has it as rectosigmoid for 50%. Robbins has rectosigmoid fo 55%.

  7. Fernando says:

    p288. Bilirubin. It says “actively taken up by hepatocytes”, but isn’t unconjugated bilirubin uptake a passive process, while excretion of bilirubin is an active (energy-dependent) process?

  8. Holly says:

    In the “official” FA error sheet, they have a correction that says for p. 287, Liver anatomy, zone III is most sensitive to toxic injury, not zone I. Can anyone explain this? I always learned that zone I was most sensitive to toxins and zone III most sensitive to ischemia. However, I also learned in our path class that phosphorous (eg, from pesticides) were most likely to affect zone I, while carbon tet affected zone III. Do you think that’s what they’re getting at with that correction?

  9. Inna says:

    p.291 under Inflammatory Bowel Disease they have Crohn’s listed as having pot-infectious etiology. To the best of my knowledge and from all that I could find it has genetic links and is considered autoimmune. Anyone know different?

  10. Eric Brinton says:

    I found this snipppet on this website: http://www.medicinenet.com/crohns_disease/article.htm

    “The cause of Crohn’s disease is unknown. Some scientists suspect that infection by certain bacteria, such as strains of mycobacterium, may be the cause of Crohn’s disease. To date, however, there has been no convincing evidence that the disease is caused by infection. Crohn’s disease is not contagious. Although diet may affect the symptoms in patients with Crohn’s disease, it is unlikely that diet is responsible for the disease.”

    So it looks like they don’t really know.

  11. Ali Baher says:

    Page 279 bottom right of the page the frequencies of the slow waves in the GI system have the wrong units. eg. Stomach is 3 waves/MIN which is different than 3 Hz (Hz means waves/SEC. same for duodenum and ileum

  12. Adam says:

    Page 278 says that portal hypertension leads to external hemorrhoids when it should be internal hemorrhoids as correctly described on page 281 in teh decussion of the pectinate line.

  13. JC says:

    p. 297 should mention Cystic Fibrosis as a cause of pancreatitis — even though it doesn’t fit into the mnemonic.

    Also, chronic pancreatitis is a disease entity that deserves mention here. Perhaps it suffices to say that chronic pancreatitis may result from several bouts of acute alcoholic pancreatitis, but it does NOT result from repeated bouts of gallstone pancreatitis.

  14. Holly Hayden says:

    Hello. This is kind of an “unconventional” question , but have other visitors asked you how get the menu bar to look like you’ve got it? I also have a blog and am really looking to alter around the theme, however am scared to death to mess with it for fear of the search engines punishing me. I am very new to all of this …so i am just not positive exactly how to try to to it all yet. I’ll just keep working on it one day at a time Thanks for any help you can offer here.

  15. Tom Tyson says:

    Absolutely love your blog! Definitely bookmarking it.

  16. Bill Andrew says:

    Thanks for the gallbladder disease information. Definitely helpful.

  17. Brock says:

    This site really has all the information I needed concerning this subject and didn’t know who to ask.

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