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THE DUCTLESS GLANDS.

ORIGINALLY BY THE LATE D. J. CUNNINGHAM, F.R.S.,

Late Professor of Anatomy, University of Edinburgh; REVISED AND REWRITTEN BY A. C. GEDDES, M.D., F.R.S.E.,

Professor of Anatomy, M'Gill University, Montreal.

e, the ductless glands, denotes a group of organs whose function is to

a special product and to discharge it into the blood or lymph. These s constitute the act of internal secretion. group includes the hypophysis and the pineal body, which are described with n; the suprarenal glands, which are compound organs and are the principal

tatives of two important systems of glandular tissue called respectively the phil and cortical systems; the glandulæ caroticæ, which are outlying parts chromaphil system; the thyreoid and parathyreoid glands, and the thymus, are developed from the entodermal lining of the embryonic pharynx ; the and the glomus coccygeum, which are associated with the circulatory system, siologically, the liver, pancreas, gastric and intestinal mucous membranes ; the kidneys, , and testes; the uterus, ovaries, corpus luteum, and possibly some other organs form secretions, and act therefore as “ductless glands” in addition to fulfilling their more functions. Anatomically, the lymph and hæmo-lymph glands are “ductless glands," 9 not customary to speak of them as such.

. THE CHROMAPHIL AND CORTICAL SYSTEMS AND THE

SUPRARENAL GLANDS.

A. THE CHROMAPHIL SYSTEM.

(SYNONYMS: Chromophil, Chromaffin, Phæochrome, Phaöchrome System.) The chromaphil system is composed of a number of discrete masses of tissue ch produce and discharge adrenin (lævo-adrenalin, C,H,3N03 (Aldrich)). The ne chromaphil is given to the tissue because the cells forming it contain nules which, in the presence of chromium salts, stain to any tint between ght yellow and dark brown. The distribution of the masses of tissue forming

system is shown in Fig. 1053. There are (i.) a series of isolated masses, the raganglia, associated singly or in groups with the ganglia of the sympathetic rvous system, (ii.) a number of masses, chromaphil bodies of the sympathetic ex uses (aortic bodies) in close relation to the abdominal sympathetic plexuses, i.) the glandule caroticæ, and (iv.) the medullary portions of the suprarenal Lands.

(i.) The paraganglia are rounded masses of chromaphil tissue, 1-3 mm. in diameter, laced inside, half inside, or immediately outside the capsules of the ganglia of the ympathetic system. Typically one paraganglion, exceptionally a pair of paraganglia, is associated with each ganglion of the gangliated trunks and with each ganglion of the celiac, renal, suprarenal, aortic, and hypogastric plexuses. Inconstantly, paraganglia

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are associated with the ganglia of the cardiac and inferior mesenteric plexuses. Ther
have been reported in association with ganglia situated upon the surface of the suprarenala interal paired
glands, upon the surface and in the sinus of the kidney, in relation to the ureter, the common care
prostate, the epididymis, the ovary, the paroöphoron, and the retro-peritoneal Pacinia and in betwee
corpuscles, but have not been discovered in association with the ganglia of the branches en is placed
of the nervus trigeminus.

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(consisting of cortex & medulla) Fig. 1053.- DIAGRAM OF THE CHROMAPHIL AND CORTICAL SYSTEMS. Modified from Swale Vincent

Chromaphil tissues=yellow ; cortical tissue = blue. (ii.) The Chromaphil Bodies of the Sympathetic Plexuses.-From seven to seventy masses of chromaphil tissue are developed in relation to the abdominal sympathetic plexuses, independently of the ganglia and in addition to the paraganglia

. Of these, the most important are the two aortic bodies, which lie one on either side of the aorta in the region of the origin of the inferior mesenteric artery. In the new-born child they are smooth brownish structures, 8-11 mm. in length, not infrequently united by an isthmus superiorly (Zuckerkandl). They degenerate as life advances, ceasing to be visible soon after puberty, but remaining discoverable, microscopically, until about the age of forty.

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glandula carotica (B.N.A. glomus caroticum; 0. T. intercarotid body) paired organ situated in close but slightly variable relation to the bifurcation non carotid artery. Frequently it lies deep to the bifurcation; sometimes it

between the internal and external carotids at their commencement; someplaced between them at a slightly higher level. Its shape varies with its Vhen free from pressure it is oval; when compressed by the internal and otids it is wedge-shaped. On the average, its height is 7 mm., its breadth

Not infrequently it is split into two or more nodules. Its colour is grayish, r brownish red. re. - The glandula carotica is built up of nodules of chromaphil tissue surrounded ced by fibrous tissue. The nodules are penetrated by a mass of sinus-like blood ind surrounded by large lymph vessels. Scattered nerve-cells are present, and the a is permeated by non-medullated nerve-fibres, which establish intimate connexion romaphil cells. he medullary portions of the suprarenal glands, although belonging to aphil system, are described below (p. 1346). pment of the Chromaphil System.-All chromaphil tissue develops in intimate

th the sympathetic nervous system. It is not derived from the sympathetic tissue = sympathetic tissue derived from it. Both are the descendants of a primitive, z sympatho-chromaphil blastema, which in a 16-mm. embryo occupies the regions ing to those occupied by the sympathetic system of the adult. It is composed of cked deeply staining cells about 5 u in diameter

. The ancestry of these cells can be Ek with strong probability to the cells of the neural crest (see Development of the tic Nervous System). ifferentiation of chromaphiloblasts from sympathoblasts begins when the embryo is mm. in length, but is not completed until late in gestation, if then. The process is y an increase in size of the chromaphil formative cells and by a diminution in the of their reaction to ordinary stains. "Later, the specific chrome reaction develops, but stage at which this occurs is unknown. It is important to note that if any cells in an rentiate, all do. The result is that, in spite of their intimate relations and common i intermixture of chromaphil and sympathetic cells is extremely rare. irst of the chromaphil masses to differentiate are the aortic bodies. They are prominent s in a 20-mm. embryo. Later, the paraganglia of the sympathetic plexuses develop, the paraganglia of the gangliated trunk. levelopment of the glandula carotica requires special description. It takes origin from of sympatho-chromaphil blastema, which extends ventrally from the region of the cervical sympathetic ganglion, deep to the internal carotid artery or between the and external carotids. Differentiation begins when the embryo is about 20 mm. in and is completed by the time it is 30 mm. long. In connexion with the development landula, there is a peculiar thickening of the wall of the internal carotid artery near the ing gland. In the dog a similar thickening of the wall of the internal carotid artery dace, although in that animal the glandula lies beside the external carotid. Further, in m. fætus in which the glandula is fully differentiated the thickening is still present. acts show that in the higher animals the thickening has no connexion with the developof the glandula, though the association of chromaphil bodies with blood-vessels in omata and elasmobranchs (see Comparative Anatomy of the Chromaphil and Cortical 18) compels caution in excluding the possibility of there being at least some phylogenetic n between the two. It has frequently been stated, and is widely held, that the glandula ca is developed from or receives some contribution from the entoderm of the third ngeal pouch. This is not the case (see Parathyreoid Glands, Development).

B. THE CORTICAL SYSTEM. The cortical system is composed of several masses of glandular tissue peculiarly in lipoids. Its function is undetermined. The distribution of the masses is wn in Fig. 1053. There are (i.) the cortical portions of the suprarenal glands, accessory cortical bodies. These are described below (see Accessory Suprarenal nds and Cortical System, Development).

C. GLANDULA SUPRARENALES. The suprarenal glands (0.T. suprarenal bodies or capsules, adrenal glands) e compound organs consisting of a capsule of cortical substance enclosing á

dulla of chromaphil tissue. Typically, there are two suprarenal glands, a ght and left, placed in the epigastric region, one on each side of the vertebral column. They lie in the same plane as, and in intimate relation to, the superimedial aspects of the kidneys. Their colour is yellowish brown; their size varie within wide limits. To some extent it depends upon the cause of death—bein: large in subjects dead of acute septic intoxication, small after sudden death from violence. Average dimensions are: height, 5 cm.; breadth, 3 cm.; thicknesi slightly under 1 cm. ; weight about 7 gm.

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FIG. 1054. A. Anterior surface of right suprarenal gland. B. Anterior surface of left suprarenal gland. The superior and medial parts of each kidney are indicated in outline. On the right gland the dotted line

indicates the superior limit of the peritoneal covering.

Rarely only one gland is present; occasionally one is quite small, the other unusually large; as a rule they are unequal in size, the left being more frequently the larger. Sometimes the two glands are fused (cf. horse-shoe kidney). Frequently there are accessory glands. These develop in the neighbourhood of the main gland, and usually remain there, but may become attached, early in embryonic life, to organs which subsequently change their position. As a result, they may be found not only beside the main gland but also in

Surface in relation to

left crus of diaphragm Surface in relation

to diaphragm

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Surface in relation

to kidney

Surface in relation
A to kidney

B

FIG. 1055.
A. Posterior surface of right suprarenal gland. B. Posterior surface of left suprarenal gland.

the ligamentum latum, on the spermatic funiculus, or even attached to the epididymis Like the main glands, accessory suprarenals are compounded of cortex and medulla, and require to be distinguished from chromaphil bodies and accessory cortical bodies, which may be found in any of the positions in which accessory suprarenal glands occur.

Forms and Relations. The suprarenal glands possess fairly constant forms and relations. The right gland is flat and triangular in outline. It is moulded, antero-laterally

antero-medially by the vena cava inferior ; postero-medially by the diaphragm by the kidney below. In a'formalin-hardened specimen these areas are

prominent ridges. Near the apex of the gland, within the area of contact a cava inferior, there is a short fissure, the hilum. From this emerges a vein diately joins the vena cava. The left gland is also flat, but is semilunar in

is moulded antero-laterally, by the stomach above, and by the pancreas of suprarenal gland

Cortex of suprarenal gland

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Intervertebral fibro-cartilage

1056.—TRANSVERSE SECTION THROUGH THE SUPRARENAL GLAND OF A NEW-BORN CHILD

IN SITU.

ostero-medially by the diaphragm above, and by the kidney below. Upon the urface, near its lower end, is a well-marked fissure, the hilum. From this emerges ich almost immediately joins the left renal vein. elations of the right and left glands to the kidneys are different. The right lies p upon the superior pole of the right kidney ; the left is in contact with the edial border of the left kidney from the hilus to the superior pole. The relation

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Fig. 1057.—RECONSTRUCTION OF SUPRARENAL GLAND OF A Dog. (From Marshall Flint.) The upper part shows the arrangement of blood vessels upon the surface of the gland, the lower part

their arrangement within its substance.

ne glands to the peritoneum is not only different but variable. On the right side the toneum may cover the lower part of the antero-lateral surface of the gland; or this may be in contact with the duodenum, in which case a small area about the middle he surface may be covered by peritoneum; or the peritoneum may not come into tion with the gland at all. On the left side the upper part of the anterior surface commonly covered by the peritoneum of the omental bursa, the lower part being

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