Cecum II

It should be noted that, upon reflection, I have seen a bigger cecum than the one noted before, but it was in a mouse infected with cholera, and as such was mostly liquid anyway.

Cecum

It's like the murine equivalent of an appendix, only with a digestive function and not just as a reservoir for normal gut flora. The jejunum feeds it and the ileum drains it, but it's pretty much a big J-shaped sack that holds digesting food. I do not know what it's contents would look like in a wild mouse with a heterogeneous diet, but in lab animals with a homogeneous diet it is uniformly brown (think pre-poop).

I bring up the cecum because I dissected out possibly the biggest cecum I have ever seen the other day. It was from a Germ-free Swiss Webster mouse, about 18 months of age, who was suffering bloat from a downstream gut twist. Ceca tend to bloat anyway in germ-free mice, and the gut twist may have backed up materials as well (although it pooped on me anyway when I picked it up), but the mouse still had retained ~3g of cecal contents (mouse weighed maybe 25g). That's incredible!

If I had the same relative mass of undigested food in me, that'd be about 9kg!

(I have a morbid tendency to calculate things upward from mice to my own mass. For example, the LD50 of Stx-2 (Shiga-like-toxin-2, produced in very virulent O157:H7 E coli strains) in mice is about 1.3E-5g/kg [if I am remembering the paper on it correctly]. Which means that the LD50 for me would be only about 3mg!).

Necropsy Practice

This is a rather smelly organ. I managed to puncture one today while practicing necropsies on mice and it oozed out of the too-deep cut I'd made into the peritoneum, sloshed down the side of the mouse and pooled in the Petri dish beneath. I've observed dissections of pathogen infected mice, and it seems that Vibrio cholerae kind of turns it into a watery, even fouler-smelling mush.

Enjoy your dinner.