The Digestive Time Table

Cecum.................................... 4 hrs.

Hepatic flexure_____________ 6 hrs.

Splenic flexure____________ 8 hrs.

Iliac colon_________________ 9 hrs.

Pelvic colon _______________ 10 hrs.

Rectum ___________________ 16 hrs.

Discharge of residues................ 18 hrs.

The X-ray shows that food often reaches the ileocecal valve within half an hour after it is taken into the mouth. It does not pass into the colon at once, however, but accumulates in the lowest coils of the ileum, which finally becomes distended to such a degree that segmentation is set up, and by this means the food is pushed forward into the cecum.

The last of the food taken into the stomach does not reach the colon until the end of about nine hours from the time it is eaten. Thus, the entire meal should reach the pelvic colon, according to Rosenheim, at the end of about fourteen hours.

The delay of six hours in the pelvic colon seems wholly unreasonable and unnecessary. If the food can pass from the splenic flexure to the pelvic colon in two hours (Rosenheim) it would seem that it ought to be able to traverse the short pelvic loop in the same length of time, or less. The processes of digestion and absorption of digested products is completed before the splenic flexure is reached. The descending colon, iliac and pelvic colon, and the rectum, contain few absorbent vessels. The feces are ready for discharge from the body; what possible benefit can result from their longer retention? Putrefaction processes are actively at work producing ptomaines and other toxins in quantity. By absorption, these may become a source of enormous and irreparable mischief. Why should not the unusable food remnants, the wastes and microbes which constitute the fecal mass, be gotten rid of as soon as possible when prepared for exit? Is it not more than probable that the lower part of the human intestine, which is most subject to the influence of voluntary interference, has been so long abused, discouraged and hindered that it has become abnormally slow and dilatory?

Evacuation Of The Colon

The evacuation of the bowels is accomplished by means of seven distinct actions, three of which are voluntary and four automatic Arranged in the order of natural sequence, the following are the several acts which together constitute normal bowel movement.

1. Descent of the diaphragm and compression of the bowels, accomplished by taking a deep breath.

2. Voluntary contraction of the abdominal muscles, increasing the compression.

3. Pressure of the thighs against the abdominal wall (natural position in moving the bowels is not the upright sitting position, but a crouching or squatting position universally employed by savages and in some pioneer rural communities).

The result of these three voluntary efforts is to force a portion of the contents of the pelvic, colon into the rectum, the distention of which gives rise to stimulation of the defecation center of the sympathetic nervous system by means of which the four automatic movements in defecation are brought into action, consisting of the following:

4. Reflex contraction of the abdominal muscles, reinforcing the voluntary contraction.

5. Contraction of the colon; the descending and pelvic colons are chiefly active, though sometimes the whole colon contracts.

6. Reflex relaxation of the anal sphincter, in obedience to the general law which holds throughout the entire digestive tube, by virtue of which a wave of contraction passing along any portion of the canal is immediately preceded by a wave of relaxation.

7. Contraction of the levator ani, a structure which surrounds the rectum and contracts at the end of defecation for the purpose of forcing out the last remnants of fecal matter, so that the rectum may remain empty until another movement occurs.

There are really eight steps in the defecation process, if we include the preliminary filling of the pelvic colon with fecal matter. A disturbance of any one of these eight factors in the process of defecation may result in constipation. If the diaphragm contracts insufficiently because of weak-if the abdominal muscles are weak, as is generally ness, tight lacing, adhesions, or any other cause, the case among civilized people, and if the position assumed in evacuating the bowels is such that the abdominal walls are not compressed by the thighs, the result may be that the rectum is not filled sufficiently to stimulate the defecation center, and so the reflex necessary to set in operation the automatic movements which empty the bowel, will not be produced.

To be effective, the distention of the rectum must be complete, and must be accomplished quickly. If the rectum is allowed to fill gradually, stimulation may not occur. If, on the other hand, distention of the rectum, as evidenced by a desire to move the bowels, is not relieved by going to stool, the desire for movement gradually disappears through the loss of sensibility of the rectal nerves, and the reflex is lost. The nerves which preside over reflex activities are easily exhausted by continued stimulation. Human physiology affords many examples of this principle.