Textbook of anatomy. Section 2. The muscular system: the nervous system: the organs of sense and integument / By D.J.Cunningham,Robert Howden and A.M.Patterson.

  • Cunningham, D. J.
Date:
1906
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Licence: In copyright

Credit: Textbook of anatomy. Section 2. The muscular system: the nervous system: the organs of sense and integument / By D.J.Cunningham,Robert Howden and A.M.Patterson. Source: Wellcome Collection.

Provider: This material has been provided by UCL Library Services. The original may be consulted at UCL (University College London)

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    V btratum conieuDi movable; but on the scalp and outer surface of the pinna, as well as on the palms and soles, it is bound down to the subjacent tissues. The skin consists of two strata, viz.: a deep, termed the dermis or corium, and a superficial, named the epidermis (Fig. 604). The corium gives elasticity and sensibility to the skin, and consists essentially of a felted interlacement of connective tissue and elastic fibres. In its deeper part, or stratum reticulare, the fibrous bundles are coarse and form an open network, in the meshes of which are vessels, nerves, pellets of fat, hair follicles, and glands. This reticular stratum passes, as a rule, without any line of demarcation, into the panniculus adiposus or subcutaneous fatty tissue, but in some parts it rests upon a layer of striped or unstri^Ded muscular fi])res—the latter in the case of the scrotum. In the superficial layer, or stratum papillare, of the corium, the connective tissae- bundles are finer and form a close network. Projecting from its free surface are numerous finger-like, single, or branched elevations, termed papillae (Fig. 605), the free ends of which are received into corresponding depres- sions on the under sur- face of the epidermis. These papillae vary in size, being small on the eyelids, but large on the palms and soles, where they may attain a length of 2'2b /X, and produce the permanent curved ridges already alluded to. Each ridge usually contains two rows of papillae, between which the ducts of the sweat glands pass to reach the surface. The papillae consist of fine connective tissue and elastic* fibres, mostly arranged parallel to the long axis of the papilla. The majority contain capillary loops, but some the terminations of nerves. The superficial surface of the corium is covered by a thin, homogeneous basement membrane. The epidermis covers the corium; it is non-vascular and consists of stratified epithelium. Its superficial layers are modified to form the stratum corneum, or horny- layer of the skin, which may be separated by maceration or blistering from the deeper, softer portion, or stratum mucosum (Malpighi). The epidermis consists from within outwards of the following five strata (Fig. 605):— 1. The basilar layer, or stratum germinativum, which comprises a single stratum of nucleated columnar cells planted by denticulated extremities on the basement membrane of the corium. 2. The stratum mucosum, which consists of six or eight layers of polygonal, nucleated prickle or finger cells, the processes of which join those of adjacent cells. Between the cells of this layer are minute channels, in which leucocytes or pigment granules may be seen. The cells of the stratum mucosum are charac- terised by the presence of numerous epidermic fibrils, which are coloured violet by ha^matoxylin and red by carmine. These fibrils are unaffected by boiling, but swell up under the action of acids and alkalies, and form the filaments of union 53 a Fig. 605. Blood-vessels and nerves -Vertical Section of Epidermis and Papilla of Corium (highly magnified).