Human physiology (Volume 2) . creted fluid passes immediately from thebloodvessel, without being received into any excretory duct; and,in the follicle, there is essentially no duct specially destined for theexcretion of the humour. The follicle is membranous and vascu-lar, having an internal cavity into which the secretion is poured ;and the product is excreted upon the surface beneath which it issituate, either by a central aperture, or by a very short duct — ifduct it can be called — generally termed a lacuna. The gland is of a more complex structure than the last. It con-sists of an artery
Human physiology (Volume 2) . creted fluid passes immediately from thebloodvessel, without being received into any excretory duct; and,in the follicle, there is essentially no duct specially destined for theexcretion of the humour. The follicle is membranous and vascu-lar, having an internal cavity into which the secretion is poured ;and the product is excreted upon the surface beneath which it issituate, either by a central aperture, or by a very short duct — ifduct it can be called — generally termed a lacuna. The gland is of a more complex structure than the last. It con-sists of an artery which conveys blood to it; of an intermediate » See the chapter on Clothing in the authors Elements of Hygiene, p. 388,Philad. 1835. 19* 222 SECRETION. body, — the gland, properly so called, — and of an excretory ductto carry off the secreted fluid, and to pour it on the surface of theskin or mucous membrane. The bloodvessel, that conveys to thegland the material from which the secretion has to be effected, Fig. Secreting Arteries, and Nerves of the Intestines. « a. A portion of the intestine, b b. Part of the aorta, ccc. Nerves following the branches of the aorta to supply the intestine. enters the organ, at times, by various branches ; at others, by asingle trunk, and ramifies in the tissue of the gland; communica-ting at its extremities with the origins of the veins and of the ex-cretory ducts. These ducts arise by fine radicles at the part wherethe arterial ramifications terminate; and they unite to form largerand less numerous canals, until they terminate in one large duct,as in the pancreas; or in several, as in the lachrymal gland ; theduct generally leaving the gland at the part where the bloodvesselenters. Of this we have a good exemplification in the kidney. The pavement and the cylinder epithelium, as weh1 as all theintermediate forms, are met with in the different glands. These arenot necessarily a continuation of that of the cutaneous system;on the
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Keywords: ., bookcentury1800, bookdecade1840, booksubjectphysiology, bookyear1
