Book I.


Necessity for This Book.—A brief outline of the structure or anatomy, and of the function, use or physiology of the human organism must necessarily inaugurate any book purporting to present the prevention and cure of disease, for disease means disordered function which cannot be understood without some knowledge of the normal or regular function, which in turn necessitates a study of structure.

Plan of the Book.—As anatomy and physiology are naturally inseparable we will interweave one with the other in the following pages, the part played by an organ being given with its description.

Bodily Organs.—Every animal is composed of organs, as the heart, liver, kidney, etc., and every organ consists of tissues, of which there are four varieties: epithelial, connective, nervous and muscular. Each tissue is made of numbers of cells.

Form of Cells.—A cell is a microscopic bag of jelly-like substance called protoplasm, which often contains within its substance a smaller cell called a nucleus, and sometimes inside the smaller cell, a tiny dot called the nucleolus.

Protoplasm.—Protoplasm is formed of water, albuminous substances, sugary material, fat and chemical salts. The chief chemical salts entering into its formation are carbon, hydrogen, oxygen and nitrogen.

Size of Cells.—Cells vary from 1/5000 to 1/120 of an inch in diameter; differ in shape; some form layers as in the skin; some bands as in muscle; some tubes as in the hair-like blood-vessels, and some float in fluid as the blood corpuscles. Some have the power of moving from place to place, ameboid motion.

Human Body Compared to a City.—The human body may be compared in its arrangement to a city, the houses being the organs; the brick, stone, wood and metal the tissues, and the individual bricks, fragments of stone, boards or pieces of metal the cells.

Human Body Compared to an Army.—Huxley compares it to an army, "each cell is a soldier, an organ a brigade, the central nervous system the headquarters and field telegraph, and the alimentary and circulatory systems the commissariat." The function of a cell is the same as that of a human being, they absorb food and grow, fill special offices, as protecting, secreting, etc., reproduce and die.

Epithelium.—Epithelial tissue or epithelium means literally upon the nipple. It covers the entire outside of the body, as the skin, the inside of the respiratory, alimentary and genito-urinary apparatuses as mucous membrane, and dips down into the various glands which open on the skin and mucous membrane.

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Skin Arrangement.—On the skin it is arranged in layers as pavement epithelium (Fig. 8) and acts as a protection to the delicate structures beneath. In some places, as in the hair and nails, it is much modified to more effectually guard against injury.

Shape in the Stomach.—In the stomach, intestines and elsewhere the epithelial cell is oblong in profile (Fig. 9) and is called columnar epithelium.

Cilia of Windpipe.—Some epithelium, like that in the windpipe, has projecting from it long waving filaments called cilia (Fig. 10). The cilia wave constantly acting as brooms which keep the windpipe clean.

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Glandular Epithelium.—Secretory or glandular epithelium (Figs. 11 and 12) is found in the glands, varies in shape, and is the essential portion of the gland, i. e., the portion which manufactures the special secretion from the blood.

Endothelium.—Endothelium, lining serous sacs, joint cavities (synovial sacs), and the blood and lymphatic vessels, is analogous to epithelium.

Connective Tissue.—Connective tissue occurs as bone, cartilage and fibrous connective tissue.

Bone Structure.—Bone is fibrous tissue cemented with petrified cement. It consists approximately of one-third animal and two-thirds earthy material, the principal earthy constituents being the phosphate and carbonate of lime; lining bone is pinkish in color and oozes blood when cut.

Periosteum.—Externally it is covered by a membrane called periosteum. The shafts of long bones are hollow, the cavity being filled by the marrow which consists of blood and lymph vessels, nerves and fat supported by fibrous tissue.

Tissue of Bones.—Bone tissue is of two kinds, spongy, which forms the very thin bones and the ends of long bones, and compact. which is found in the shafts of long bones and in the outside of flat bones. Spongy bone is made up of a meshwork of bony arches, the spaces filled with vessels, bone cells and connective tissue.

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Compact Bone.—Compact bone (Fig. 5) consists of a series of concentric layers of bone disposed around a canal called the Haversian canal which affords passage for the blood-vessels. The layers of bone are separated from each other by small spaces called lacunae, and passing through the bony layers and connecting the lacunae are many fine channels called canaliculi; they serve to convey nourishment to the bone cells. The function of bone is to support, to protect, and to give attachment to muscles.

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Structure of Gristle.—Cartilage or gristle (Fig. 4) is fibrous tissue glued together by a substance containing chondrine. It has no blood-vessels but is nourished by lymph which filters through it by means of small spaces and canals analogous to the lacunae and canaliculi of bone.

Use of Gristle.—Cartilage forms a smooth covering for the ends of bones entering into a joint; acts as a buffer between the bones of the spine, prevents certain tubes, like the windpipe, from collapsing, and as in the external ear gathers sound.

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Fibrous Tissue.—Fibrous tissue consists ultimately of fibres which are developed from spindle-shaped cells. Its function is to hold the various parts of, and the organs themselves, together. Fatty tissue ( Fig. 3) is fibrous connective tissue unfiltrated with fat.

Nervous. Tissue.—Nervous tissue is either gray, which is a mass of tailed cells (Fig. 57) supported by a fine connective tissue (neuroglia), or white, which is made of bundles of little nerve febrils, each febril is the tail of a cell in the gray nervous tissue and is surrounded in some places by the white substance of Schwann (Fig. 58) and by a primitive sheath.

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Muscular Tissue.—There are two kinds of muscular tissue, the voluntary or striped and the involuntary or non-striated. Voluntary muscle (Fig. 6) is composed microscopically of the primitive fasciculi (minute bundles of febrils), each febril of which consists of a row of disks (Fig. 6) called sarcous elements. Involuntary muscle is built of a number of non-striped spindle-shaped cells (Fig. 7) which branch and join with one another.

Framework of the Body.—The body skeleton (Fig. 13) forms the framework of the body. Bones are divided into long, short and flat bones. The long bones consist of a hollow shaft of compact bone, and two broader extremities of cancellated bone. They are found in the extremities and form levers by which the trunk is moved.

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