When you say that the outer surface of the intestines does not have nerves, you must mean sensory pain fibers. I don't know if this is true or not. Just because normal peristalsis does not cause pain does not necessarily mean that there are no pain fibers. However, the intestine is a smooth muscle and muscles need nerves to move. I have read that IBS, for example, is thought to be a disruption in the innervation of the bowel, cause unknown. Sometimes it works too slow, sometimes too fast. Once when I posted that I read this about IBS I was told that the intestines do not have nerves,so when I saw this again, I thought some clarifaction would help. I agree the textbook is a bit technical but did not feel I had the qualifications to use my own interpretation so I let the textbook speak for itself. It is not that difficult once you figure out what viscera, viscus etc is. I looked those words up and included the definitions in parenthesis.
-- ChrisAt Sat, 23 Dec 2000, Helen Dynda wrote: > >It is very evident that the intestines do have nerves; BUT the sensory >nerves are within the intestines themselves. Inflammatory Bowel Disease >( IBD ) is a very good example of this!! And there are other bowel >diseases, which cause pain. > >Perhaps I should have been more specific when I said: "The intestine is >a muscle. It does NOT have nerves!!" > >Actually,I was referring to the "outer surface" of the intestines...the >part of the intestines which, through the process of peristalsis, causes >food to move through the digestive tract and finally to elimination. I >still believe that this part of the intestines does not have nerves. > >I can't argue with a textbook definition; because I have great >difficulty trying to understand the information given there. But I do >appreciate the fact that you did share this information on the Message >Board. > >As to the exact interpretation of the information from the textbook, I >think that perhaps the interpretation of that information should be left >to those, who practice medicine. > >At Sat, 23 Dec 2000, chris wrote: > >Helen: >The intestines do have nerves. They are smooth muscles and muscles >require innervation to work. There are also pain fibers in the >intestines. It is true that different kinds of problems cause more or >less pain, depending on what it is. > >Taken from my physiology textbook: > >"In Clinical diagnosis, pain from the different viscera (guts i.e. >intestines) of the abdomen and chest is one of the few criteria that can >be used for diagnosing visceral inflammation, disease, and other >ailments. In general the viscera have sensory receptors for no other >modalities of sensation besides pain and visceral pain differs from >surface pain in many important aspects." > >This is what you might be thinking of- "One of the most important >differences between surface pain and visceral pain is that highly >localized types of damage to the viscera rarely causes severe pain. For >instance, a surgeon can cut the gut entirely in two in a patient who is >awake without causing significant pain. (my interpretation of this is >that cutting only the gut would do this, not through the muscles etc to >get to the gut, that would cause extreme pain) On the other hand, any >stimulus that causes diffuse stimulation of pain nerve endings >throughout a viscus (visceral organ such as instestine) causes pain that >can be extremely severe. For instance, occluding the blood supply to a >large area of gut stimulates many diffuse pain fibers at the same time >and can result in extreme pain." > >Also "any stimulus that excites pain nerve endings in duffuse areas of >the viscera (organ) causes visceral pain. (in other words, not the >localized type of pain described above)Such stimuli include ischemia >(decreased blood supply) of visceral tissue, spasm of the smooth muscle >in a hollow viscus (organ), chemical damage to the surfaces of the >viscera, distention of a hollow viscus (such as gas pain), or stretching >of the ligaments (not sure what this means) > >This is a bit technical but does point out that the visceral organs such >as the intestine do have pain fibers. It depends on the problem how >much they are stimulated. If you do a search "intestinal innervation" >you will see many many articles on the innervation of the gut. You are >right, when the peritoneum is stimulated (i.e. when adhesions attach >the intestines to the peritoneal wall) that causes pain also. > >Chris > >At Sun, 10 Dec 2000, Helen Dynda wrote: > >If the intestines are attached to the peritoneum or another abdominal >organ, the peristalsis of the intestines WILL "pull" and thus cause pain >that can be described as being a "burning" pain. > >The intestine is a muscle. It does NOT have nerves!! > >Definition of "peristalsis" -- the coordinated, rhythmic, serial >contraction of smooth muscle that forces food through the digestive >tract. "