. Outlines of the comparative physiology and morphology of animals. Anatomy, Comparative; Physiology, Comparative. 326 PHYSIOLOGY AND MORPHOLOGY OF ANIMALS. by the great length of the intestines, still more by the many folds of the mucous membrane (valvules conniventes) (Fig. 207), but most of all by the villi. These micro- scopic hairlike projections g~£/». Fig. 208.—Two of the villi, greatly enlarged ; one showing blood cap- illaries, the other, the lacteals: ep, epithelium. cover the surface as thick- ly as the pile of velvet or the tufts of Brussels car- pet. They give a velvety- feel to t
. Outlines of the comparative physiology and morphology of animals. Anatomy, Comparative; Physiology, Comparative. 326 PHYSIOLOGY AND MORPHOLOGY OF ANIMALS. by the great length of the intestines, still more by the many folds of the mucous membrane (valvules conniventes) (Fig. 207), but most of all by the villi. These micro- scopic hairlike projections g~£/». Fig. 208.—Two of the villi, greatly enlarged ; one showing blood cap- illaries, the other, the lacteals: ep, epithelium. cover the surface as thick- ly as the pile of velvet or the tufts of Brussels car- pet. They give a velvety- feel to the mucous mem- brane (Fig. 208). Each villus contains two kinds of absorbent vessels—viz., capillary blood vessels and lacteals. These, though separated in the figure, are both of them in each villus. Two Modes of Absorption.—The food is ab- sorbed in two ways—viz., by blood capillaries and by lac- teals. The blood capillaries contain a circulating current, and therefore take up the food and carry it along with the blood. The lacteals, on the contrary, are purely absorbent, and they end in blind, fingerlike extremities, and therefore suck up the liquid food. Whatever of food is absorbed by the stomach is wholly by blood capil- laries. But the intestines are specially organized for absorption in both ways. The food is divided between these two modes. The sugars are absorbed mainly by the capillaries, the fats by the lacteals, while the pep- tones are divided between them. Course of Each to the General Circulation.— That taken up by the capillaries is carried to the por- tal vein ; thence it passes through the liver, and by the hepatic vein it reaches the vena cava ascendens and by it is carried to the heart, and is thence distributed every-. Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not perfectly resemble the original LeConte,
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