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TABLE OF CONTENTS.
Physiology, from qúols, nature, and lóyos, a discourse, in its original application embraced the study of all natural objects, inorganic as well as organic. In its modern application physiology signifies the study of life; the investigation of the vital phenomena exhibited by all organic bodies, vegetable and animal.
It may be divided into1. Vegetable physiology, which treats of the phenomena manifested by
the several structures of which the plant is composed. 2. Animal physiology, which treats of the phenomena manifested by the
organs and tissues of which the animal body is composed. Human Physiology is the study of the functions exhibited by the human body in a state of health.
A Function is the action of an organ or tissue.
groups, viz. :
1. Nutritive functions, which have for their object the preservation of
the individual; e.g., digestion, absorption, circulation of the blood,
respiration, assimilation, animal heat, secretion and excretion. 2. Animal functions, which bring the individual into conscious relation
ship with external nature; e.g., sensation, motion, language, mental
and moral manifestations. 3. Reproductive function, which has for its object the preservation of
the species. The facts of human physiology have been determined by means of anatomy, chemistry, pathology, comparative anatomy, vivisection, the application of physics, etc. The Body may be studied from a chemical and structural point of view.
CHEMICAL COMPOSITION OF THE HUMAN
BODY. Of the Sixty-four Chemical Elements, about sixteen enter into the composition of the body, in the following proportions :Oxygen.........72.00 O. H. and C. are found in all the tissues and Hydrogen...... 9.10
fluids of the body, without exception. Nitrogen...... 2.50 O. H. C. and N. found in most of the fluids Carbon .... .13.50
and all tissues except fat. Sulphur. .147 ......In fibrin, casein, albumen, gelatin; as potas
sium sulpho-cyanide in saliva; as alkaline
sulphate in urine and sweat. Phosphorus .... 1.15 ...... In fibrin and albumen; in brain; as tri-sodium
phosphate in blood and saliva, etc. Calcium......... 1.30 ...... As calcium phosphate in lymph, chyle, blood,
saliva, bones and teeth. Sodium......... ......As sodium chloride in all fluids and solids of
the body, except enamel; as sodium sul
phate and phosphate in blood and muscles. Potassium...... .026 ......As potassium chloride in muscles; generally
found with sodium as sulphates and phos
phates. Magnesium.... .001 ....Generally in association with calcium, as phos
phate, in bones. Chlorine........ .085 ......In combination with sodium, potassium and
other bases, in all the fluids and solids.
.08 ...... As calcium fluoride in bones, teeth and urine. Iron .....
.. In blood globules; as peroxide in muscles. Silicon ......
...... In blood, bones and hair. Manganesium, a trace .Probably in hair, bones and nails.
Of the four chief elements which together make up 97 per cent. of the body, O. H. N. are eminently mobile, elastic, and possess great atomic heat. C. H. N. are distinguished for the narrow range and feebleness of their affinities and chemical inertia. C. has the greatest atomic cohesion. (). is noted for the number and intensity of its combinations, and its remarkable display of chemical activity.
Chemical Elements do not exist alone in the body, but are combined in characteristic proportions to form compounds, the proximate principles, which are the ultimate compounds to which the fluids and solids can be reduced,