Table Of ContentAN INTRODUCTION TO
GASTRO - ENTEROLOGY
A CLINICAL STUDY OF THE STRUCTURE
AND FUNCTIONS OF THE HUMAN
ALIMENTARY TUBE
BY
JAMES DUNLOP LICKLEY, M.D.
Hon. Consulting Physican, Sick Children's Hospital, Newcastle-upon-Tyne;
Late Lecturer on Medical Applied Anatomy, Medical School,
King's College, University of Durham.
WITH 21 ILLUSTRATIONS
BRISTOL: JOHN WRIGHT & SONS LTD.
LONDON: SIMPKIN MARSHALL (1941) LTD.
1947
PRINTED IN Ο REA Τ BRITAIN BY
JOHN WRIGHT AND SONS LTD.
BRISTOL. ENGLAND.
PREFACE
THIS elementary manual is intended for those beginners
who are interested in approaching from a scientific
aspect the study of some of the problems arising in the
diagnosis and treatment of disorders of the alimentary
tube. It is hoped, therefore, that it may appeal to
senior medical students and to the younger physicians.
At the same time, since the subject is of such everyday
importance, much of the information provided in this
simplified form may be of interest and help to the
general practitioner.
To the medical men returning from the Forces, the
résumé of anatomical and physiological data given
herein may prove of some assistance in their post-war
revision courses.
In a manual of this size and scope no useful purpose
would be served by indicating specifically the numerous
sources from which information has been derived. The
literature of gastro-enterology embraces several hundred
articles; for lists of the more important of these the
student is referred to the larger text-books.
J. D. L.
INTRODUCTION
THE study of the alimentary tube can be approached from
several angles, e.g., anatomical, physiological, pathological,
bacteriological, etc. In the present manual the lines of
approach selected are the anatomical, the physiological, and
the clinical. The volume of literature which has grown
up in connexion with each of these is enormous. Observa-
tions, experiments, and deductions have accumulated until
it is almost impossible for anyone commencing this study
to construct for himself even a crude working plan that he
might use as a basis for his investigations into the practical
problems he seeks to understand.
It is useful, therefore, to make an attempt to present to the
beginner a simplified story of the structure and working of
this important tube. Such simplification demands the selec-
tion of certain details and the omission of many more. It
necessitates an individual outlook, and as such is open to
much criticism, but it does not ignore the fact that once a
definite picture has been established, there is a huge pool of
information from which verification and amplification of
details can be drawn, and it is hoped that further study along
these lines may be stimulated and an added interest given
to the subject.
The present attempt at simplification has as its ultimate
object the practical application of some well-known ana-
tomical and physiological facts and theories to several of
the simpler medical clinical conditions ; only such details,
therefore, are selected as are considered to have a direct
bearing on the problems to be discussed.
VÜi INTRODUCTION
In order to present the subject in the clearest possible
manner it is proposed to consider it under the following
headings :—
Part I.—The structure and divisions of the alimentary
tube.
Part II.—How the tube works under normal conditions.
Part III.—How the working of the tube is modified by
certain abnormal conditions.
Part IV.—Some practical clinical applications.
PART I
THE STRUCTURE AND DIVISIONS OF
THE ALIMENTARY TUBE
"While the student may direct his attention especially to the
phase of structure or the phase of function, he should understand
from the outset that great progress and permanent results are to be
attained only when the study of structure and the study of function
go hand in hand."
J. B. JOHNSTON.
AN INTRODUCTION TO
GASTRO-ENTEROLOGY
CHAPTER I
THE GENERAL STRUCTURE AND
DIVISIONS OF THE ALIMENTARY TUBE
THE alimentary tube is a long continuous tube with an inlet
at the mouth and an outlet at the anus (Fig. i).
From a functional point of view, it is possible to divide it
broadly into three segments. The first segment extends
from the inlet of the tube to the middle of the duodenum and
may be described as preparatory; here the foodstuffs are
mechanically and chemically prepared for presentation to
the next segment, but are not sufficiently altered to allow
of any absorption. The second segment extends from the
middle of the duodenum to the middle of the transverse
colon; in it all the main digestive and absorptive processes
are accomplished. The third segment, which extends from
the middle of the transverse colon to the outlet of the tube,
may be described as expulsive; it is almost entirely devoted
to the rejection of such portions of the foodstuffs and other
waste materials as cannot be utilized by the body.
For a more detailed study of the structure and functions
of the alimentary tube, it is convenient to divide it into a
series of compartments each presenting definite differences
in structure that can be related to specific functions (Fig. 2).
These compartments are as follows:—
Compartment I.—Lips to the faucial isthmus.
Compartment II.—Faucial isthmus to the cardiac orifice of
the stomach.
4 GASTRO-ENTEROLOGY
Fig. ι.—Scheme of the usual structural divisions of the alimentary tube.
GENERAL STRUCTURE OF ALIMENTARY TUBE 5
Fig. 2.—Scheme of the proposed functional divisions (compartments) of
the alimentary tube.
6 G ASTRO-EN TE ROLOGY
Compartment HL—Cardiac orifice of the stomach to the
middle region of the duodenum.
Compartment IV.—Middle of the duodenum to the middle
region of the transverse colon.
Compartment V.—Middle of the transverse colon to the anal
canal.
Compartment VI.—The anal canal.
Attention is drawn particularly tç the fact that in this
description the anatomical division of the abdominal part
of the alimentary tube into stomach, small intestine, and
colon is replaced by one which closer study will show con-
forms more intimately to embryological, anatomical, and
physiological findings.
The fundamental pattern of the wall of the tube may be
studied readily in a transverse section taken from the lower
part of the small intestine. The outermost coat is the peri-
toneal covering—tunica serosa. Under this is the muscular
coat—tunica muscularis—arranged in two layers, namely,
an outer of longitudinal and an inner of circular fibres. The
innermost coat of the tube is the mucous membrane—tunica
mucosa—and in it may be recognized: (i) A surface layer
of epithelial cells and simple glands resting on a basement
membrane; (2) A layer of retiform tissue containing scattered
lymph-cells; (3) A layer of very thin unstriped muscular
tissue—the muscularis mucosae. The tunica muscularis is
connected to the tunica mucosa by a loose but strong layer
of areolar tissue—the submucous layer—in which run the
larger blood-vessels and nerves of the wall of the tube.
The fundamental pattern undergoes modifications in the
separate parts of the alimentary tube, and these will be indi-
cated as they are encountered in the course of the description.
