United States or Monaco ? Vote for the TOP Country of the Week !
There is reason to believe that, once present, the growth of feathers was modified greatly by the degree of stimulation applied to the papillae at roots by the movement and bending strain of the feathers.
The histology of ainhum shows it to be a direct ingrowth of epithelium, with a corresponding depression of surface due to a rapid hyperplasia that pushes down and strangles the papillae, thus cutting off the blood supply from the epithelial cells, causing them to undergo a horny change. The disease is not usually symmetric, as formerly stated, nor is it simultaneous in different toes.
Immediately after the breeding season the horny epidermis of the pad with its deeply pigmented papillae is cast off, and the thumb remains comparatively smooth from April or May until August or September. When the large papillae are shed, smaller papillae remain beneath, and are gradually obliterated by the epidermis growing up between them.
THE CORONARY CUSHION projects into the upper border of the wall. It is covered with vascular papillae which secrete the horny fibres that form the wall. The vascular laminae are leaf-like projections, the sides of which are covered by secondary leaves. Horny laminae, arranged the same as vascular laminae, line the wall.
The skin consists of two layers, the derma, or true skin, and the epidermis, or cuticle. It is the principal seat of the sense of touch, and on the surface of the upper layer are the sensitive papillae, which receive and respond to impressions; and within, or imbedded beneath it, are organs with special functions, viz., the sweat glands, hair follicles and sebaceous glands.
For a couple of hours, I fix my attention on a Volucella grub established in a cell, side by side with the Wasp grub, the mistress of the house. The hind quarters emerge, displaying their papillae. Sometimes also the fore part, the head, shows, bending from side to side with sudden, snake-like motions.
Then Indifference comes; she stretches herself on the divan, taking no care to draw down the skirts of her robe which Desire but now lifted so chastely and so eagerly. She casts a glance upon the nuptial bed, with modesty and without shamelessness; and, if she longs for anything, it is for the green fruit that calls up again to life the dulled papillae with which her blase palate is bestrewn.
These two structures are so firmly united that it is impossible to tear them apart without destroying the tissue. The velvety tissue covers all of the inferior surface of the foot, with the exception of the bars. As the name indicates, its surface is covered by vascular papillae that resemble the ply on velvet. It is firmly united to the horny sole which it secretes.
There are no associated constitutional symptoms, no tendency to similar morbid changes in other parts, and no infiltration elsewhere. There is little or no edema with ainhum. In ainhum there is, first, simple hypertrophy, then active hyperplasia The papillae degenerate when deprived of blood supply, and become horny.
It seems impossible that the horny layer or its papillae could atrophy in consequence of castration, or be absorbed. Meisenheimer claims that he produced development of papillae on the thumb-pad, not only by implantation of pieces of testis, but also by implantation of pieces of ovary.
Word Of The Day