The helical movement of sebum

Of all the sebaceous glands, the rat sebaceous preputial glands, due to their size and accessibility, are particularly useful for research. These are two elongated, symmetrical glandular masses, located in the subcutaneous cellular tissue on either side of the penis or clitoris. Up to the third week of age, they are pyriform and pearly white in color. They later become fl attened, yellowish-pink in color and increase markedly in volume until, between the seventh and tenth week, they reach 12 to 15 mm in length and 5 to 6 mm in width. The confi guration is similar in both sexes, although adult males usually have larger glands and longer extraglandular excretory ducts [2].


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It is estimated that helical is the movement of planets in the solar system, the DNA format, the pathway of the excretory ducts of the eccrine sweat glands in the human epidermis, the evolution of our thoughts when they improve and even as banality, the movement of water in our washbasins towards the drain pipes.
And what happens with the movement of sebum of the sebaceous glands?

In lemurs
In 1962, W. Montagna verifi ed that in some lemurs (primates from Madagascar), the path of the ducts of the sebaceous glands that are independent of the hairs is helical and appears colored black by melanin produced by melanocytes in the interior of the sebaceous glands [1].

In the rat sebaceous preputial glands
Of all the sebaceous glands, the rat sebaceous preputial glands, due to their size and accessibility, are particularly useful for research. These are two elongated, symmetrical glandular masses, located in the subcutaneous cellular tissue on either side of the penis or clitoris. Up to the third week of age, they are pyriform and pearly white in color. They later become fl attened, yellowish-pink in color and increase markedly in volume until, between the seventh and tenth week, they reach 12 to 15 mm in length and 5 to 6 mm in width. The confi guration is similar in both sexes, although adult males usually have larger glands and longer extraglandular excretory ducts [2].
The secretory units of the rat preputial sebaceous glands are tubuloacinous, formed by glandular acini with basal cells, in the beginning of differentiation, differentiated, completely differentiated and in disaggregation, similarly to what happens in the human skin sebaceous glands. In addition, the glands have a rich ductular network constituted by numerous secondary excretory canals of different caliber that converge in a single main excretory duct ( Figure 1) [3].
The lining epithelium of the excretory duct is initially a simple squamous one and progressively stratifi es as it approaches the main excretory duct. In this there are 6 to 8 layers of overlapping cells, the number reaching 15 layers near the opening of the duct in the preputial meatus [3].
The keratinization that occurs in the main excretory duct of this gland is of the soft type and the fi ne morphology of the cellular structures that compose it is identical to the epidermis and excretory ducts of the sebaceous glands in the man's skin [3].
The chemical composition of the secretion product is very similar to human sebum [4] and the hormonal response to androgens, to estradiol and to orchidectomy is identical [2,3,5,6].

Research Article
The helical movement of From our side, we can see that in the rat sebaceous preputial glands on the right side of the body, the movement of the sebum is levorotatory, whereas in those on the left side the movement is dextrorotatory, i. e., clockwise.

And in the human sebaceous glands?
The same is observed in the pilosebaceous follicles of In the follicular canal, the sebum does not move in any way, i. e., the sebum is not limited to being pushed by a secretion that is continually renewed. Although this is the case in the excretory ducts that immediately follow the sebaceous glands, where the peeling of the soft fl at cells of the wall does not interfere with the movement of sebum, in the follicular canal the panorama is different. The sebum travels in a space limited by hard structures that are the wall of the follicular canal and the hair. This means that in the follicular canal the sebum movement becomes disciplined and the hair acts as a drain. Furthermore, the insertion of the excretory duct of the sebaceous glands in the follicular canal is oblique, the hair is convex, the canal is concave, the hair also has an oblique position in relation to the skin surface and, consequently, the movement of the sebum is helical (Figure 3).
I insist that, similarly to what happens with the helical movement of the sebum in the rat sebaceous preputial glands, in the pilosebaceous follicles of the human skin the movement of the sebum is levorotatory in the right half of the body and in the opposite direction, i. e., dextrorotatory in the left half.