Soft tissue

“ We observe the structure of the skin—whether it be fine or coarse in its texture, whether it be hard and unyielding, or soft and elastic. We note the quantity of fat and of cellular tissue; and this enables us to form a judgment respecting the degree of embonpoint, and we have already abundantly proved that a man of a soft, lax habit, with an abundance of cellular and fatty tissues, differs in mental tendency and disposition from one of firm, tense fibre, in whom the bones, muscles, and articulations, are strong and prominent. ”

“ Cartilaginous tissue forms smooth coverings over the ends of the bones and, in addition to this, supplies the necessary stiffness in organs like the larynx and the ear. The nervous tissue controls the body and brings it into proper relations with its surroundings, while the epithelial tissue (found upon the body surfaces and in the glands) supplies it with protective coverings and secretes liquids. The adipose tissue (fat) prevents the too rapid escape of heat from the body, supplies it with nourishment in time of need, and forms soft pads for delicate organs like the eyeball. ”

“ Those important tissues with which the embalmer should be more or less acquainted are the following:
Skin, nails, hair, superficial fascia, deep fascia, lymphatics, glands, cartilage, bone, teeth, nerves, muscles, tendons, aponeuroses, ligaments, fat, mucous membranes, serous membranes, synovial membranes, arteries, veins and blood.
The Skin.
—The skin or integument (intego, to cover) is the outside covering of the human body. It is the first tissue that is cut when operating upon the body.
Fig. 2—A cross section of the skin. (Gray)
The skin is the seat of the organs of touch. ”

“ The cuticle, epidermis, or scarf-skin, as it is indifferently termed, is formed of cells or scales, much flattened and horny in the upper layers, rounder and plumper below. The true skin, or “cutis,” is fibrous in structure, and lies immediately beneath, the two together constituting the skin, properly so called. Beneath lies a layer of tissue filled with fatty globules, and containing the glands by which the perspiration is secreted. ”

“ When, during life, one tissue is separated from another, as the periosteum from the bone, or the cuticle from the skin, or the mutual cohesion between different tissues is sensibly weakened, we find it to be owing to the intervention of serous fluid which does not belong to their healthy state; and this, together with increased vascularity, or redness and heat, and pain, is enough to bespeak the presence of inflammation. ”

“ The skin is remarkably complex in its structure, and is divided into two distinct layers, which may be readily separated: the deeper layer,—the true skin, dermis, or corium; and the superficial layer, or outer skin,—the epidermis, cuticle, or scarf skin.
The true skin consists of elastic and white fibrous tissue, the bundles of which interlace in every direction. Throughout this feltwork structure which gradually passes into areolar tissue are numerous muscular fibers, as about the hair-follicles and the oil glands. ”

“ These constitute the true skin, but under them lies a third layer of cellular tissue, which is considered also as part of the skin, when that word is used in its most comprehensive sense. In man the skin is covered more or less with scattered hairs, profuse in some parts and scanty in others. The office of the skin is one of protection to the organs beneath, and it is also a vast excretory system, sending out quantities of perspiration through the sudoriferous glands located in its texture. ”

“ It produces a superficial substance which plays the part of the epidermis and grows outwardly. For since the surface, subject to friction and exfoliation, has to be continually renewed, there must be a continual reproduction of an outermost layer from a layer beneath. That is to say, the contact of this deep-seated tissue with outer agencies, produces in it some approach towards that character which we find universally characterizes outer tissue. ”

“ Of the Composition of the Tissues and of the Secretions in Health and Disease.—Having described thus individually the constituents of the tissues, we shall now present such results as have been hitherto obtained as to the quantitative composition of the organized tissues formed by their reunion, their secretory products and morbid alterations.
The skin of animals is a congeries of finely constructed organs, sensitive and secretory, imbedded in a peculiar tissue, which is one of those most yielding gelatine, whence the process of tanning skins. ”

“ The superficial layer, the epidermis or cuticle, is composed wholly of epithelial cells, of which the deepest layer is columnar and moulded upon the papillary layer of the derma, while the intermediate layers are more rounded and the surface ones flat. The deepest layer also contains the skin pigment, which causes the variation in shade between the Indian, the negro, and the white man. Below the epidermis, which is chiefly protective, is the tough, elastic, and flexible tissue of the derma or true skin, in which are vested most of the activities of the skin. ”

“ They may often be seen in sections, and are lined with nucleated cells, similar to those of the glands. These are surrounded by coatings of unstriped muscular fibre, running both around and lengthways, and also by connective-tissue fibres. In the arteries, the muscular coating is much stronger than in the veins. ”

“ The bony palate of all mammals is covered with a closely-adhering layer of fibro-vascular tissue, the surface of which is protected by a coating of non-vascular epithelium, the former exactly corresponding to the derm or true skin, and the latter to the epiderm of the external surface of the body. ”

“ The surface of the skin only may be affected—that and the subjacent cellular tissue may be involved, gorged with serous, lymphatic, or purulent infiltration—there may exist great tension of the parts, with a sloughy state of the cellular tissue, established in addition to suppuration—and again, there may be infiltration of the subfascial and intermuscular tissues, leading ultimately to exposure and exfoliation of bones or disease of articulations. ”

“ The CELLULAR TISSUE, [2] now called the areolar tissue, consists of small fibres, or bands, interlaced in every direction, so as to form a net-work, with numerous interstices that communicate freely with each other. These interstices are filled, during life, with a fluid resembling the serum of blood. The use of the areolar tissue is to connect together organs and parts of organs, and to envelop, fix, and protect the vessels and nerves of organs. ”

“ These tissues of mixed character form what is called connective tissue, which is found throughout the body.
Fat is deposited in little cells situated in the connective tissue.
Muscular tissue, which forms the great bulk of the body, is easily recognized by its ruddy color, and it constitutes what is known as “flesh.” It is fibrous, and if these fibers be examined under the microscope there will appear, in those under the influence of the will, transverse markings, while the muscles not under the will-power lack these markings. ”

“ When the action is more violent, and is not actively opposed, lymph is effused on the inner surface of the membrane, or is deposited amongst the ligamentous and cellular tissues external to the joint, in consequence of which, the membrane and external ligaments become thickened, and of an almost cartilaginous consistence. Serum is effused into the more superficial cellular tissue, filling up the hollows around the joint, concealing the protuberances of the bones, and producing a globular swelling. ”

“ The walls of this tissue offer the strongest resistance to the most various agencies, similar to the cuticular layers of the epidermis in their physical behavior, flexible and elastic, permeable only with difficulty by air and water, they for the most part soon lose their contents and become filled with air. ”

“ The internal layer is the rete mucosum. It lies immediately upon the true skin, and consists solely and wholly of cells, being equally destitute of vessels and nerves. Here begin the first discrepancies in the opinion of writers. Some deny that it belongs to the epidermis, looking upon it as a separate substantive tissue, neither skin nor scarf-skin, but intermediate to the two. Others find it only in the coloured families of mankind. It occurs, however, universally; being of a yellowish-white colour in Europeans, and dark brown or black in negroes, Indians, and the so-called dark races. ”

“ Unobtrusive, and yet to be found at every point, are the ducts of the lymphatic system. And in all parts exists the connective tissue—an inert tough substance which, running through interspaces, wraps up and binds together the other tissues. As is implied by this description, these structures stand in contrast with local structures. Here is a bone, there is a muscle, in this place a gland, in that a sense-organ. Each has a limited extent and a particular duty. But through every one of them ramify branches of these universal structures. ”

“ Such a simple mode of division does not occur in the more highly specialized cells of various tissues. If the karyokinetic action be not very vigorous, the nucleus may divide, but the cell body remains intact, producing the cell with two or more nuclei so commonly observed. Every cell reproduces its kind, spindle cells producing connective tissue; epithelial cells epithelium; and bone cells producing bone.
Repair of Wounds and Healing by Apposition. When a wound occurs, the cut edges immediately retract on account of the elasticity of the tissues, and the gap fills with blood and serum. ”

“ In a work of this limited size the sensibility of the various tissues cannot be fully treated but it should be borne in mind that the integument and the subcutaneous tissue, fat and muscles as well as the tendons, their sheaths, the muscles and periosteum and perichondrium covering the bones and cartilages throughout the body, are all highly sensitive to pain. It is also equally true that the bone substance, the bone marrow, and the cartilages are devoid of any of the four modalities of sensation. ”

“ They are “folds so disposed that the thick skin shall be capable of bending in grasping while it at the same time requires to be tightly bound down to the skeleton of the hands and feet, so as to prevent slipping of the skin which would necessarily lead to insecurity of prehension, just as the quilting and buttoning down of the covers of furniture by upholsterers keeps them from slipping. For this purpose the skin is tied by fibres of white fibrillar tissue to the deep layer of the dermis along the lateral and lower edges of the palmar fascia and to the sheaths of the flexor tendons. ”

“ The skin, being richly supplied with nerves, is an important organ of sensibility and touch. In some parts it is closely attached to the structures beneath, while in others it is less firmly adherent and rests upon a variable amount of fatty tissue. It thus assists in relieving the abrupt projections and depressions of the general surface, and in giving roundness and symmetry to the entire body. The thickness of the skin varies in different parts of the body. Where exposed to pressure and friction, as on the soles of the feet and in the palms of the hands, it is much thickened. ”

“ The sensibility in the last is much greater than in the first, because the impressions can more easily penetrate through the soft epithelium, with which the internal cavities are invested, than through the hard cuticle, because the compact fibrous membrane of the true skin does not suffer the vibrations to pass freely up the nerve through its own substance, but rather diffuses them along its surface, and because the moisture of the epithelium dissolves, and thereby renders active all the saline particles, which touch the internal cavities. ”

“ Although entirely different in nature and chemical composition, the cartilage tissue serves to maintain certain outlines of form and feature in the human body, which are not based on the still stronger forms of supporting material, such as the bone tissue and the gelatigenous tissue. ”

“ Experiments in the laboratory and in practice have shown that it is not the dissolving action on the skin substance in the narrow sense which is desired in bating the derm with dogs’ dung, but in order to prepare the hide for the manufacture of a soft and elastic leather, the albuminous intercellular substances and more particularly the layers of fat lying at the roots of the hair, in the corium and in many cases also on the epidermis, must be dissolved and thereby the fibrils of the skin loosened. ”

“ Specimens can easily be obtained to illustrate the structure of the tissues. By a skillful use of the microscope and knives the subject will cease to be hard and uninteresting. A fowl carefully dissected illustrates the tendons, ligaments of the fibrous tissue. Muscular tissue is well seen in a piece of beef. The structure of nervous tissue and course of the nerves may be studied in any small animal. Adipose tissue, or fat, is easily obtained.
P. 375, c. 1.—“Skeleton.” To thoroughly understand the human skeleton, one should, if possible, be obtained for study ”

“ The gap in the muscle becomes filled with blood, and this in time is replaced by connective tissue, which forms a bond of union between the ends. When the space is considerable the connecting medium consists of fibrous tissue, but when the ends are in contact it contains a number of newly formed muscle fibres. ”

“ They attack by preference the tissues derived from the mesoblastic layer of the embryo--the cellular tissue, bones, muscles, and viscera. They are often localised to one particular tissue or organ, such, for example, as the subcutaneous cellular tissue, the bones, or the liver, and they are rarely symmetrical. ”