Essentials of physiology for veterinary students / by D. Noël Paton.

  • Diarmid Noel Paton
Date:
1908
Catalogue details

Licence: Public Domain Mark

Credit: Essentials of physiology for veterinary students / by D. Noël Paton. Source: Wellcome Collection.

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    The fats are esters usually of the triatomic alcohol glycerin— ( OH c,hJ oh (oh by the replacement of the hydrogen of the hydroxyl molecules by the radicles of the fatty acids. The most abundant fatty acids of the body are :— Palmitic Acid, C16H3]0,0H Stearic Acid, C18H350,0H Oleic Acid, C18H330,0H and from these the three fats— Palmitin, C3H5(0,C16H310)3 = C61H98Oc Stearin, C3H5(0, C18H350)3 = C67H110O6 Olein, C3H5(0,C18H330)3 = C67H104O6 are produced. It will be observed that the molecules of these fats are very rich in carbon and hydrogen, and very poor in oxygen— i.e. they contain a large amount of material capable of being oxidised, and thus capable of affording energy in the process of combustion. The fats resemble one another in being insoluble in water, but soluble in ether and in hot alcohol. As the alcohol cools, they separate out as crystals. They differ from one another in their melting point, palmitin melting at the highest and olein at the lowest temperature. Fat which is rich in palmitin and stearin, as ox fat, is thus hard and solid at the ordinary temperature of the air, while fats rich in olein, as dogs’ fats, are semi-fluid at the same temperature. The olein acts as a solvent for the fats of a higher melting point. (For tests, see Chemical Physiology.) The functions of adipose tissue are twofold:— 1st. Mechanical.—The mass of adipose tissue under the skin is of importance in protecting the deeper structures from injury. It is a cushion on which external violence expends itself. Further, this layer of subcutaneous fat prevents the loss of heat from the body, being, in fact, an extra garment. 2nd. Chemical.—Fat, on account of its great quantity of unoxidised carbon and hydrogen, is the great storehouse of energy in the body (p. 393).
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