McMurrich1914 Chapter 14
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McMurrich JP. The Development Of The Human Body. (1914) P. Blakiston's Son & Co., Philadelphia, Pennsylvania.
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Chapter XIV. The Suprarenal System of Organs
To the suprarenal system a number of bodies of peculiar structure, probably concerned with internal secretion, may be assigned. In the fishes they fall into two distinct groups, the one containing organs derived from the ccelomic epithelium and known as intervened organs, and the other consisting of organs derived from the sympathetic nervous system and which, on account of the characteristic affinity they possess for chromium salts, have been termed the chroma ffine organs. But in the amphibia and amniote vertebrates, while both the groups are represented by independent organs, yet they also become intimately associated to form the suprarenal bodies, so that, notwithstanding their distinctly different origins, it is convenient to consider them together.
The Development of the Suprarenal Bodies
The suprarenal bodies make their appearance at an early stage, while the Wolffian bodies are still in a well-developed condition, and they are situated at first to the medial side of the upper ends of these structures (Fig. 211, sr). Their final relation to the metanephros is a secondary event, and is merely a topographic relation, there being no developmental relation between the two structures.
In the human embryo they make their appearance at about the beginning of the fourth week of development as a number of proliferations of the ccelomic epithelium, which project into the subjacent mesenchyme, and are situated on either side of the median line between the root of the mesentery and the upper portion of the Wolffian body. The various proliferations soon separate from the epithelium and unite to form two masses situated in the mesenchyme, one on either side of the upper portion of the abdominal aorta. In certain forms, such as the rabbit, the primary proliferations arise from the bottom of depressions of the ccelomic epithelium (Fig. 223), but in the human embryo these depressions do not form.
Up to this stage the structure is a pure interrenal organ, but during the fifth week of development masses of cells, derived from the abdominal portion of the sympathetic nervous system, begin to penetrate into each of the interrenal masses (Fig. 224), and form strands traversing them. At about the ninth or tenth week fatty granules begin to appear in the interrenal cells and somewhat later, about the fourth month, the sympathetic constituents begin to show their chromaffine characteristics. The two tissues, however, remain intermingled for a considerable time, and it is not until a much later
Fig. 223. - Section through a Portion of the Wolffian Ridge of a Rabbit Embryo of 6.5 mm.
Ao, Aorta; ns, nephrostome; Sr, suprarenal body; vc, cardinal vein; wc, tubule of
Wolffian body; wd, Wolffian duct. - (Aichel.)
period that they become definitely separated, the sympathetic elements gradually concentrating in the center of the compound organ to become its medullary substance, while the interrenal tissue forms the cortical substance. Indeed, it is not until after birth that the separation of the two tissues and their histological differentiation is complete, occasional masses of interrenal tissue remaining imbedded in the medullary substance and an immigration of sympathetic cells continuing until at least the tenth year (Wiesel).
A great deal of difference of opinion has existed in the past concerning the origin of the suprarenal glands. By several authors they have been regarded as derivatives in whole or in part of the excretory apparatus, some tracing their origin to the mesonephros and others even to the pronephros. The fact that in some mammals the cortical (interrenal) cells are formed from the bottom of depressions of the coelomic epithelium seemed to lend support to this view, but it is now pretty firmly established that the appearances thus presented do not warrant the interpretation placed upon them and that the interrenal tissue is derived from the ccelomic epithelium quite independently of the nephric tubules. That the chromaffine tissue is a derivative of the sympathetic nervous system has long been recognized.
During the development of the suprarenal glands portions of their tissue may be separated as the result of unequal growth and form what are commonly spoken of as accessory suprarenal glands, although, since they are usually composed solely of cortical substance, the term accessory interrenal bodies would be more appropriate. They may be formed at different periods of development and occur in various situations, as for instance, in the vicinity of the kidneys or even actually imbedded in their substance, on the walls of neighboring blood-vessels, in the retroperitoneal tissue below the level of the kidneys, and in connection with the organs of reproduction, in the spermatic cord, epididymis or rete testis of the male and in the broad ligament of the female.
Fig. 224. - Section through the Suprarenal Body of an Embryo of 17 mm.
A, Aorta; R, interrenal portion; S, sympathetic nervous system; SB, sympathetic cells
penetrating the interrenal portion. - (Wiesel.)
It seems probable that the bodies associated with the reproductive apparatus are separated from the main mass of interrenal tissue before the immigration of the sympathetic tissue and before the descent of the ovaries or testes, while those which occur at higher levels are of later origin, and in some cases may contain some medullary substance, being then true accessory suprarenals. Such bodies are, however, comparatively rare, the great majority of the accessory bodies being composed of interrenal tissue alone.
Independent chromamne organs also occur, among them the
Fig. 225. - Section of a Cell Ball from the Intercarotid Ganglion of Man be, Blood capillaries; ev, efferent vein; S, connective-tissue septum; I, trabecular - (From Bohm and Davidoff, after Schaper.)
intercarotid ganglia and the organs of Zuckerkandl being especially deserving of note. It may also be pointed out, however, that the chromamne cells have the same origin as the cells of the sympathetic ganglia and may sometimes fail to separate from the latter, so that the sympathetic ganglia and plexuses frequently contain chromamne cells.
The Intercarotid Ganglia
These structures, which are frequently though incorrectly termed carotid glands, are small bodies about 5 mm. in length, which lie usually to the mesial side of the upper ends of the common carotid arteries. They possess a very rich arterial supply and stand in intimate relation with the branches of an intercarotid sympathetic plexus, and, furthermore, they are characterized by possessing as their specific constituents markedly chromamne cells, among which are scattered stellate cells resembling the cells of the sympathetic ganglia.
They have been found to arise in pig embryos of 44 mm. by the separation of cells from the ganglionic masses scattered throughout the carotid sympathetic plexuses. These cells, which become the chromamne cells, arrange themselves in round masses termed cell balls, many of which unite to form each ganglion, and in man each cell ball becomes broken up into trabecule by the blood-vessels (Fig. 225) which penetrate its substance, and the individual balls are separated from one another by considerable quantities of connective tissue.
Some confusion has existed in the past as to the origin of this structure. The mesial wall of the proximal part of the internal carotid artery becomes considerably thickened during the early stages of development and the thickening is traversed by numerous blood lacunae which communicate with the lumen of the vessel. This condition is perhaps a relic of the branchial capillaries which in the lower gill-breathing vertebrates represent the proximal portion of the internal carotid, and has nothing to do with the formation of the intercarotid ganglion, although it has been believed by some authors (Schaper) that the ganglion was derived from the thickening of the wall of the vessel. The fact that in some animals, such as the rat and the dog, the ganglion stands in relation with the external carotid and receives its blood- supply from that vessel is of importance in this connection.
The thickening of the internal carotid disappears in the higher vertebrates almost entirely, but in the Amphibia it persists throughout life, the lumen of the proximal part of the vessel being converted into a fine meshwork by the numerous trabecular which traverse it. This carotid labyrinth has been termed the carotid gland, a circumstance which has probably assisted in producing confusion as to the real significance of the intercarotid ganglion.
The Organs of Zuckerkandl
In embryos of 14.5 mm. there have been found, in front of the abdominal aorta, closely packed groups of cells which resemble in appearance the cells composing the ganglionated cord, two of these groups, which extend downward along the side of the aorta to below the point of origin of the inferior mesenteric artery, being especially distinct. These cell groups give rise to the ganglia of the prevertebral sympathetic plexuses and also
Fig. 226. - Organs of Zuckerkandl from a New-born Child. a, Aorta; ci, inferior vena cava; i.c, common iliac artery; mi, inferior mesenteric artery; n.l and n.r, left and right accessory organs; pl.a, aortic plexus; u, ureter; v.r.s, left renal vein. - (Zuckerkandl.) to peculiar bodies which, from their discoverer, may be termed the organs of Zuckerkandl. Each body stands in intimate relation with the fibers of the sympathetic plexuses and has a rich blood-supply, resembling in these respects the intercarotid ganglia, and the resemblance is further increased by the fact that the specific cells of the organ are markedly chromamne.
At birth the bodies situated in the upper portion of the abdominal cavity have broken up into small masses, but the two lower ones, mentioned above, are still well defined (Fig. 226). Even these, how- # ever, seem to disappear later on and no traces of them have as yet been found in the adult.
Literature
A. Kohn: "Ueber den Bau und die Entwickelung der sog. Carotisdruse," Archiv.
fur mikrosk. Anat., lvi, 1900.
A. Kohn: "Das chromaffine Gewebe," Ergebn. der Anat. und Entwickelungsgesch., xii, 1902.
H. Poll: "Die vergleichende Entwicklungsgeschichte der Nebennierensysteme der Wirbeltiere," Hertwig's Handb. der vergl. und exper. Entwicklungslehre der Wirbel tiere, in, 1906.
A. Sotjlie: "Recherches sur le developpement des capsules surrenales chez les Vertebres," Journ. de V Anat. et de la Physiol., xxxix, 1903.
J. Wiesel: "Beitrage zur Anatomie und Entwickelung der menschlichen Nebenniere," Anat. Heft., xix, 1902.
E. Zuckerkandl: "Ueber Nebenorgane des Sympathicus im Retroperitonealraum des Menschen," Verhandl. Anat. Gesellsch., xv, 1901.
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McMurrich JP. The Development Of The Human Body. (1914) P. Blakiston's Son & Co., Philadelphia, Pennsylvania.
Cite this page: Hill, M.A. (2024, April 18) Embryology McMurrich1914 Chapter 14. Retrieved from https://embryology.med.unsw.edu.au/embryology/index.php/McMurrich1914_Chapter_14
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