Physiology : a manual for students and practitioners . al surface of the cutis vera are innumerableminute elevations which project into the epithelium. They arevery vascular, and contain the nerve-endings which give to the skinits sensibility, the sense of touch. The papillae are especially abun-dant upon the parts in which this sense is most acute—palms, finger-tips, soles. Describe the sweat-glands. Each gland lies in the subcutaneous fat, and consists of a con-voluted mass of tubules which terminates in a duct leading upthrough the derma and epidermis, discharging the secretion of thegland
Physiology : a manual for students and practitioners . al surface of the cutis vera are innumerableminute elevations which project into the epithelium. They arevery vascular, and contain the nerve-endings which give to the skinits sensibility, the sense of touch. The papillae are especially abun-dant upon the parts in which this sense is most acute—palms, finger-tips, soles. Describe the sweat-glands. Each gland lies in the subcutaneous fat, and consists of a con-voluted mass of tubules which terminates in a duct leading upthrough the derma and epidermis, discharging the secretion of thegland through a minute opening. This secretion is known as per-spiration or sweat. What is meant by the term insensible perspiration ? When the secretion of the sweat-glands forms in drops upon theskin, we speak of this as sensible perspiration or sweat. However,at all times the glands continue active and the fluid evaporates rap- THE SKIN. 71 idly, so that no moisture is noticeable upon the surface ; and we callthis the insensible perspiration. Fig. Sectional View of the Skin, magnified. What is the sweat ? Tt is a watiTY fluid, oolorless. sli<:htly turbid, slightly salty to thetaste, of acid reaction, and possessing a peculiar odor. It is anexcrement. Its composition is somewhat variable, but in general it 72 SECEETION. may be said to contain about J per cent, of solids suspended anddissolved in water. These solids are fats and fatty acids, sodiumchloride, epithelium, and a trace of urea. Besides these there is aconsiderable amount of carbonic dioxide (CO2) excreted by theskin. What is the amount of sweat excreted in twenty-four hours ? About one and a half to two pints, but this varies greatly withthe environment. What factors affect the amount of the sweat ? The condition of the atmosphere, the nature and quantity of thefood, the amount of fluids consumed, the exercise taken, and therelative activity of the other glands, especially of the mental conditio
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Keywords: ., bookcentury1800, bookdecade1890, booksubjectphysiology, bookyear1
