General physiology; an outline of the science of life . ls, however, the intestinal cells are somewhatmodified. They are cylindrical cells that possess upon their freesurface, turned toward the lumen ofthe intestine, a striated border. AsThanhoffer (74) has shown, this stri-ated border represents really nothing-more or less than fine, pseudopodium-like, protoplasmic processes, which canbe extended and retracted, and withwhich the cells, exactly like Amain,flow around the fat-droplet and drawit into its body (Fig. 45, B). The phenomena are wholly dif-ferent in the second type of food-ingestion,
General physiology; an outline of the science of life . ls, however, the intestinal cells are somewhatmodified. They are cylindrical cells that possess upon their freesurface, turned toward the lumen ofthe intestine, a striated border. AsThanhoffer (74) has shown, this stri-ated border represents really nothing-more or less than fine, pseudopodium-like, protoplasmic processes, which canbe extended and retracted, and withwhich the cells, exactly like Amain,flow around the fat-droplet and drawit into its body (Fig. 45, B). The phenomena are wholly dif-ferent in the second type of food-ingestion, where the cell has a firmersuperficial layer of a fixed form, andonly a small opening, the cell-mouth,which leads directly into the liquidendoplasm. Here the movement ofthe cilia and flagella of the cellexclusively mediates the ingestion ofsolid substances. The delicate Vor-ticella may serve as an example, a ciliate infusorian whose bell-shaped cell-body sits upon a contractilestalk and bears at its broad end a spiral-like circlet of cilia (Fig. 46).. Fig. 44.—Leucocyte from the frog de-vouring a bacterium. Three suc-cessive stages in the ingestion offood. (After Metschnikoff.)
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Keywords: ., bookcentury1800, bookdecade1890, bookidgen, booksubjectphysiology
