BASIC SUBJECTS

LASTS ANATOMY REGINAL AND APPLIED 9th Edition PDF

LASTS ANATOMY REGINAL AND APPLIED 9th Edition PDF

LASTS ANATOMY REGINAL AND APPLIED 9th Edition PDF
LASTS ANATOMY REGINAL AND APPLIED 9th Edition PDF  The body is composed of four basic tissues — epithe lium, connective tissue, muscle and nerve—and every part of the body that is examined with either the naked eye or the microscope can only be made up of one or more of these four elements. There are of course different kinds of these tissues depending on the differing functional requirements of the various organs and parts of the body, and the details of cell types and intercellular substances are dealt with in texts on histology. This chapter brings together some notes on certain body tissues and structures to form a relevant introduction to regional anatomy.

LASTS ANATOMY REGINAL AND APPLIED 9th Edition PDF

SKIN
Skin consists of two elements: epithelium and connec tive tissue. The epithelium of the skin, which is given the special name of epidermis, is of the stratified squamous keratinizing variety. The various skin appendages—sebaceous glands, sweat glands, nails and hair — are specialized derivatives of this epidermis, which is ectodermal in origin. The connective tissue part of the skin, which is mesodermal in origin, is the dermis, consisting mainly of bundles of collagen fibres together with some elastic tissue, blood vessels, lymphatics and nerve fibres, all embedded in ground substance. When dried the dermis makes greenhide; when tanned it makes leather.

LASTS ANATOMY REGINAL AND APPLIED 9th Edition PDF
The uppermost layer of the epidermis is the stratum
corneum (Fig. 1.1), the cornified or horny layer,
consisting of dead cells (keratin) that have lost their nuclei and that are constantly being rubbed off and
replaced by cells moving up from deeper layers. In the
scalp scaly flakes of the hor.  ny layer may be trapped by hairs instead of falling off invisibly, so forming dandruff.
Fig. 1.1 Sections of thick skin, on the left, and thin skin on the right. The definition of thick and thin depends on the thickness of the keratinized layer; the overall depth of the combined epidermis and dermis is the same.
The horny layer is normally softened by the greasy secretion of sebaceous glands and moistened somewhat by the watery secretion of the sweat glands. Fat solvents or emulsifiers remove the grease and leave the horny layer stiff and harsh. Undue contact with water macer ates the keratin which, by imbibition, becomes thick, soft and white (‘washerwoman’s fingers’).

LASTS ANATOMY REGINAL AND APPLIED 9th Edition PDF

The terms thick skin and thin skin refer to the thick ness of the cornified layer (Fig. 1.1). In thick skin, such as on the sole of the foot, the stratum corneum is thick and paradoxically the dermis is relatively thin. In thin skin such as on the front of the forearm the stratum corneum is thin but the dermis relatively thick.

LASTS ANATOMY REGINAL AND APPLIED 9th Edition PDF

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