Quain's elements of anatomy . nly traces of it remain at that time, and theseare rarely discoverable beyond the twenty-fifth or thirtieth year. Structure.—The lateral lobes of the thymus gland are each investedby a thin capsule of areolar tissue, which sends partitions into the glandbetween the lobules : on its outer surface the capsule is covered by alayer of flattened cells. Each lobe consists of numerous polyhedrallobules, connected by a more delicate intervening areolar tissue. Theseprimary lobules are made up of a number of small nodules or follicles(fig. 464, &, i), one to two millimetre
Quain's elements of anatomy . nly traces of it remain at that time, and theseare rarely discoverable beyond the twenty-fifth or thirtieth year. Structure.—The lateral lobes of the thymus gland are each investedby a thin capsule of areolar tissue, which sends partitions into the glandbetween the lobules : on its outer surface the capsule is covered by alayer of flattened cells. Each lobe consists of numerous polyhedrallobules, connected by a more delicate intervening areolar tissue. Theseprimary lobules are made up of a number of small nodules or follicles(fig. 464, &, i), one to two millimetres in diameter. Each follicle 542 THE THYMUS GLAND. is composed of a central part or medulla, and an external larger part orcortex. The cortex is in many respects similar in structure to an ordi-nary lymphoid follicle, such as those of the tonsils or of Peyers patchesin the intestine : consisting, like these, of retiform tissue composed of anetwork of branched cells, and of a fine reticulum (Watney), the meshes Tis. Fig. 463.—The thymus in a chili> of six jionths (Sappey). A. Situation, form and relations of the gland. 1, right lobe; 2, left lobe ; 3, medianfurrow ; 4, lung, somewhat everted ; 5, internal mammary vein ; 6, thyroid body ;7, 8, inferior thyroid veins, mesial and lateral ; 9, common carotid artery; 10, internaljugular vein; 11, pneumogastric nerve. B. Eight lobe of the thymus after removal ofits envelope ; 1, its apex ; 2, its base ; 3, thin outer border; 4, thick inner The gland unravelled, showing the lobules grouped around a central cord ; 4, thecentral cord or strand of connective tissue, connecting the lobules. of both being filled with lymphoid cells (thymus corpuscles) ; at the sur-face of the foUicle the retiform tissue is somewhat closer, so as to form aspecies of capsule for it. In some animals these capsules completely enclosethe follicles, but in others, including man, several follicles may be unitedtowards the centre of the lobul
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Keywords: ., boo, bookcentury1800, booksubjectanatomy, booksubjecthumananatomy
