From:
Sukie Crandall
Date: 2009-02-14 22:29:05 UTC
Subject: [ferrethealth] I've noticed an oft-repeated statement that plant matter is digested in the cecum
To: fhl <ferrethealth@yahoogroups.com>
I've noticed an oft-repeated statement that plant matter is digested=20
in the cecum, but that is not so! The break down happens mostly in=20
the duodenum and jejunum, with most nutrients absorbed in the ileum. =
(Those are the three sections of the small intestine.) Yes, ferrets=20
have all three.
The cecum (which means blind pouch) is located just beyond the small=20
intestine at the start of the sections of the large intestine (colon),=20
and is discussed as part of the large intestine in articles on colonic=20
motility (for example, appendicitis can induce not only constipation=20
but complete loss of motion). Current thinking is that the appendix=20
serves mostly as a hideaway for symbiotic bacteria (which are more=20
important for animals with diet rich in plant matter) so that when=20
events like diarrhea occur there is a quick way to repopulate.=20=20=20
Carnivores are less likely to need that whereas those with more plant=20
matter in the diet greatly need those bacteria. So, the connection=20
between having that is now thought to not be a direct digestion=20
aspect. Instead it appears that those who are more likely to need to=20
quickly repopulate symbiotic intestinal bacteria after diarrhea --=20
namely those with more plant matter in their diet -- have more need of=20
a cecum.
The large intestine's biggest functions are fluid removal and=20
formation of the fecal matter for excretion.
Some resources of various types:
This has a reasonable and very accessible description:
http://www.mamashealth.com/organs/intestine.asp
Here is where the confusion is happening. People are thinking that=20
the cecum is the small intestine. It is NOT.
This will help:
http://www.medterms.com/script/main/art.asp?articlekey=3D2658
QUOTE
Cecum: The cecum (also spelled caecum), the first portion of the large=20
bowel, situated in the lower right quadrant of the abdomen.
The cecum receives fecal material from the small bowel (ileum) which=20
opens into it. The appendix is attached to the cecum.
The word "cecum" comes from the Latin "caecus" meaning "blind." This=20
refers to the fact that the bottom of the cecum is a blind pouch (a=20
cul de sac) leading nowhere.
END QUOTE
Now, ferrets lack an appendix. The appendix in recent studies appears=20
to be a very useful hideaway for the symbiotic bacteria which are so=20
important for the digestion of plant materials. When they suffer a=20
natural assault (diarrhea from illness, for example) the intestinal=20
tract can repopulate from the ones that hid away in the appendix.
This is good for accuracy, and very accessible for more detail:
http://www.sparknotes.com/101/biology/nutrition_and_digestion/components_of=
_the_vertebrate_digestive_system.html
including
QUOTE
The small intestine is split into three sections: the duodenum,=20
jejunum,and the ileum. Chemical digestion takes place in the duodenum=20
and the jejunum. The ileum, the final section of the small intestine,=20
is where most absorption of the nutrients takes place. Small=20
projections called villi cover the ileum walls. Cells lining the villi=20
are covered in folds of plasma membrane that form even smaller=20
projections called microvilli. Villi and microvilli increase the=20
ileum=92s surface area, providing more surface across which nutrients=20
can be absorbed. Nutrients pass through capillaries in the lining of=20
the villi and into the bloodstream, where they circulate first to the=20
liver, then throughout the rest of the body. Villi and microvilli=20
projections also contain digestive enzymes to further digest food.
END QUOTE
The original study on the appendix as a symbiotic bacteria safe house:
in
http://www.ncbi.nlm.nih.gov/sites/entrez
QUOTE
J Theor Biol. 2007 Sep 7; [Epub ahead of print]
Biofilms in the large bowel suggest an apparent function of the human=20
vermiform appendix.
Randal Bollinger R, Barbas AS, Bush EL, Lin SS, Parker W.
Department of Surgery, Duke University Medical Center, Box 2605,=20
Durham, NC 27710,
USA; Department of Immunology, Duke University Medical Center, Durham,=20
NC 27710,
USA.
The human vermiform ("worm-like") appendix is a 5-10cm long and=20
0.5-1cm wide pouch
that extends from the cecum of the large bowel. The architecture of=20
the human appendix
is unique among mammals, and few mammals other than humans have an=20
appendix at all.
The function of the human appendix has long been a matter of debate,=20
with the structure
often considered to be a vestige of evolutionary development despite=20
evidence to the
contrary based on comparative primate anatomy. The appendix is thought=20
to have some
immune function based on its association with substantial lymphatic=20
tissue, although the
specific nature of that putative function is unknown. Based (a) on a=20
recently acquired
understanding of immune-mediated biofilm formation by commensal=20
bacteria in the
mammalian gut, (b) on biofilm distribution in the large bowel, (c) the=20
association of
lymphoid tissue with the appendix, (d) the potential for biofilms to=20
protect and support
colonization by commensal bacteria, and (e) on the architecture of the=20
human bowel, we
propose that the human appendix is well suited as a "safe house" for=20
commensal bacteria,
providing support for bacterial growth and potentially facilitating re-
inoculation of the
colon in the event that the contents of the intestinal tract are=20
purged following exposure
to a pathogen.
PMID: 17936308 [PubMed - as supplied by publisher]
END QUOTE
I DID find an interesting abstract for another reason:
QUOTE
Current Opinion in Gastroenterology:Volume 24(6)November 2008p 720-724
Symbiotic commensal bacteria direct maturation of the host immune system
[Immunology: Edited by W. Allan Walker]
Edelman, Sanna Ma,b; Kasper, Dennis La,b
aChanning Laboratory, Department of Medicine, Brigham and Women's=20
Hospital, USA
bDepartment of Microbiology and Molecular Genetics, Harvard Medical=20
School, Boston, Massachusetts, USA
Correspondence to Dennis L. Kasper, MD, Channing Laboratory, Brigham=20
and Women's Hospital, 181 Longwood Avenue, Boston, MA 02115, USA
Abstract
Purpose of review: Although commensal bacteria are known to play an=20
important role in the proper maturation of the immune system of their=20
mammalian hosts, the molecular mechanisms underlying this=20
immunomodulation are poorly characterized. The present review=20
summarizes recent findings in the field and describes new knowledge on=20
the interplay of the innate and adaptive arms of the immune response=20
induced by symbiotic bacterial carbohydrate antigens.
Recent findings: Commensal bacteria in the intestine not only interact=20
directly with dendritic cells but also engage in cross-talk with=20
epithelial cells. These interactions lead to the induction of=20
tolerogenic antigen-presenting cells in the lamina propria and=20
ultimately to the regulation of functional maturation of effector T=20
cells. Upon recognition of capsular polysaccharide antigens of=20
commensal bacteria by dendritic cells (through toll-like receptor 2),=20
innate immune responses facilitate and act in conjunction with=20
adaptive responses to promote optimal Th1 polarization. In contrast,=20
adaptive immunoglobulin A responses to symbiotic bacteria regulate the=20
magnitude of oxidative innate immune responses in the mucosa as well=20
as bacterial epitope expression in the lumen.
Summary: Accumulating evidence is elucidating surface carbohydrate=20
structures of symbiotic bacteria that drive the modulation of the=20
intestinal immune system, resulting in mature, balanced immune=20
responses and oral tolerance.
=A9 2008 Lippincott Williams & Wilkins, Inc.
END QUOTE
and
this is cool for other reasons:
http://www.academycme.org/monographs/0803casestudies.pdf
I recall an abstract which I think (but am not certain) that I sent to=20
the FHL in the past on how the interactions of the pancreas, liver and=20
gall bladder also take signals from the small intestine and interact=20
in other ways, too, and recall it was fascinating but not what the=20
nuances were. It was possibly a Triad Disease abstract though not=20
necessarily, and I lack time to find it.
Also, those who wonder when bacteria go wrong will find info on when
inflammation and breaks in the normal colonic mucus layer spiral in:
http://www.ncbi.nlm.nih.gov/pubmed/16908512
*****Anyway, the bottom line is that the cecum and the appendix that=20
derives from that segment of the colon/large bowel/large intestine is=20
NOT the small intestine and it does NOT digest plant matter, but it=20
does appear to serve a function as a symbiotic bacteria safe-house for=20
those species who digest a lot of plant matter.*****
Sukie (not a vet)
Recommended ferret health links:
http://pets.groups.yahoo.com/group/ferrethealth/
http://ferrethealth.org/archive/
http://www.afip.org/ferrets/index.html
http://www.miamiferret.org/fhc/
http://www.ferretcongress.org/
http://www.trifl.org/index.shtml
http://homepage.mac.com/sukie/sukiesferretlinks.html
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