The Abdominal and Pelvic Brain
Byron Robinson, M. D.
1907
CHAPTER XXVI.
GASTROINTESTINAL SECRETION.
"Youth's Lexicon has no such word as fail." - Bulwer.
"It is our hearers who inspire us." - Vinet.
1. Gastrointestinal secretion is a significant
and important matter in animal life. Gastrointestinal secretions
are under the control of the sympathetic ganglia located in the walls of
the digestive tract. We designate those ganglia in general as the
Billroth-Meissner plexuses (plexus myentericus internus) situated immediately
beneath the gastrointestinal mucosa. They rule secretion. We
cannot properly separate the submucous nerve plexus from the Auerbach's
plexus (plexus myentericus externus) which rules muscular motion and is
situated between the circular and longitudinal muscles of the gastrointestinal
tract. One nerve plexus is a complement of the other. As secretion
without motion is of little avail, and motion without secretion is equally
futile, peristaltic motion is necessary to sweep onward the food to be
attacked by fresh glandular secretion and to eliminate and drain the system
from the debris of food. The remnants of the gastrointestinal feast
must be removed by peristaltic movements.
Besides, secretion is doubtless enhanced by the
massage muscular contractions. The large degree of independence exercised
by the sympathetic ganglia, especially at a long distance from the cerebrospinal
center, is quite suggestive that there will be local as well as general
gastrointestinal mucous secretion. From the very construction and
function of the digestive tract we may expect local labors in it.
At several localities new and different secretions are added to the onward
moving food, so that local and general digestion and secretion must occur.
I repeat that secretion and digestion are both local and general in regard
to the digestive tube. Yet the whole nerve apparatus of the digestive
tract is a delicately balanced matter both as regards muscular and secretary
activity. Let us call up matters that daily occur, but are
not always interpreted. For example, a person eats some cucumbers
or other indigestible and fermentable substance. At the time that
the indigestible substance is eaten the bowels may be as regular as clockwork
and the feces of semi-liquid character. Ten hours after eating the
indigestible substance, when the regular stool is to be evacuated, it will
be observed that: (1) the stool is delayed, the desire for stool is checked;,
(2) if forced evacuation be exercised, the stool will be hard and relatively
dry, for want of secretion is manifest by distinctly formed and shaped
feces.
Now what is the cause of this disturbance?
The cause is unbalanced secretion due to reflex irritation. The irritation
is going on in the business portion of the digestive tract, i. e., in the
small intestines. The subject is conscious of this disturbance only
by a little pain, colic and excessive peristalsis. He, however, notices
that an excess of gases is being formed and passed per rectum. He
may not sleep well, but recognizes an indefinable restlessness. This
irritation may be active enough to produce seminal emissions during sleep.
The irritation in the small intestines has unbalanced the mechanism of
secretion, so that it is called away from the large intestine, causing
excessive secretion in the small intestine, and hence the dry formed feces
in the large. It is very likely that the excessive, deficient or
disproportionate secretions may occur in separate localities of the digestive
tract, just as peristalsis of the tract may be a local matter. We
know from experiment that peristalsis may arise, continue and subside,
limited to a short piece of intestine.
DUCTUS BILIS ET DUCTUS PANCREATICUS
Fig. 80.
Drawn from cross section of the pancreatic and binary duct. The
minute glands of Theile may be observed in the walls of the ducts.
These are the so-called glands of the hepatic duct. The figure illustrates
the vast domain of secretion. |
The view of local disturbance in both peristalsis
and secretion sending out its reflex power and disturbing the whole digestive
tract is in accord with pathologic data. For example, a perforation
of the appendix may so unbalance the nerve apparatus as to feel it at the
umbilicus. It is a reality. The secretion of the gastrointestinal
mucosa is entirely beyond the control of the will. In secretions
we are especially dealing with the sympathetic nerve, for secretions have
a close relation to the size of the blood vessels.
1. All glands receive vessels.
2. All vessels have nerves to control their
caliber.
The gastric secretion may be reviewed in regard
to experimental data. The stomach is supplied with nerves for its
muscles and for its glands, as motion and secretion are both necessary
for normal digestion. The Arrangement of the Auerbach and Billroth-Meissner
plexuses is similar to the small intestines. The splanchnic nerve
is the chief vasomotor nerve, i. e., vasodilator and vasoconstrictor.
This is important, for secretion in general depends on the blood supply,
as may be observed in location in the season of "rut," in glandular congestion.
But the gastric glands are ruled by the sympathetic nerves, whose chief
origin exists in the abdominal brain.
It must be claimed, however, that the stomach glands
can act independently, from sympathetic influence alone, and also be changed
or modified by the cerebrospinal. It is doubtless true that there
are not only vasomotor nerves in the spinal cord but that the abdominal
brain is a great vasomotor center, in that the abdominal brain regulates
the amount of blood to the gastric glands and consequently the amount,
and to a certain degree the kind, of secretion of the stomach. Yet
there must be secretary nerves in the stomach which belong to the sympathetic.
Candor requires the statement that the full knowledge of the nerve supply
of the gastric glands is not fully known.
The independence of the sympathetic ganglia of the
stomach is signified by the fact that the chief stimulus to the gastric
secretion is food in the stomach. It is asserted by some that stimulating
any of the nerves going to the stomach does not influence the secretion,
for it is found that secretion will go on under the stimulus of food when
all the stomachic nerves are severed. It is claimed, therefore, that
the sympathetic ganglia in the stomachic walls are sufficient to act as
centers for secretion. This delegates large and significant powers
to the sympathetic ganglia.
The sympathetic ganglia are especially liable to
reflex irritation, and nowhere is it more manifest than in the stomach.
The gastric secretion is modified by reflex stimuli from the brain, uterus,
kidney. testicle, ovary, heart and spinal cord, etc., etc. Emotions
play a role in gastric secretion The successful treatment of stomachic
disease is significant in methods of stimulating the stomach, as irritating
its mucous wall, which not only starts secretion, but motion as well.
In ordinary stomach diseases there are four factors, viz.: (a) excessive
secretion, (b ) deficient secretion, (c) disproportionate secretion, and
(d) muscular motion. Washing the stomach, irritating its wall with
instruments or coarse food, will accomplish much in inducing health.
Doubtless this is the action of nux vomica and hot water. The clinging
germs should be washed from the dormant stomach wall and the muscular movements
must be stirred to excite natural secretions. It has astonished me
at the frequent beneficial results of irrigation of the stomach.
It stirs to more normal rhythm the sympathetic ganglia, both of secretion
and motion. Besides, it washes from the stomach wall abnormal matter.
The stomach must have rest and repose or it cannot long stand irregular
irritation without
CROSS SECTION OF URETER
Fig. 81.
Presents the tunica mucosa, muscularis and serosa of the ureter, with
several nerve ganglia located between the tunica serosa and muscularis. |
resentment of the little circulation insults. Hence the distal
irritation from a diseased uterus, oviducts and ovaries sooner or later
unbalances stomach function by its regular passage of the traumatic insults
to the abdominal brain where reorganization occurs, perhaps with multiplication
of effects. The excitation of the diseased genitals has no season
of rest, no day or night repose, but at any or all times it rushes and
flashes, now tumultuous or turbulent, now pell mell and explosive.
There is nothing like a chronic atrophic myometritic uterus to derange
and unbalance the gastric secretion and motion.
The stomach is very highly supplied with blood-vessels and
nerves, because it is a vast and complicated laboratory, requiring much energy
to hold its delicate but active processes in the balanced order. From
experimental data we may view the stomachic glands as under the control of the
sympathetic nerves, i. e., the ganglia in them.
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