. Biology of the laboratory mouse. Mice as laboratory animals; Mice; Animals, Laboratory; Mice. HISTOLOGY i6i between the parenchymatous elements. The appearance of the epithehal cells of the alveoli is not uniform, indicating different phases of secretory activity. In some cells the nucleus is in the middle of the cell and the cyto- plasm is homogeneous. In others the cytoplasm appears foamy or contains large protruding fat droplets. If the litter is small and all the nipples are not suckled, some of the glands may undergo partial regression while others are still functioning (16,35). The you
. Biology of the laboratory mouse. Mice as laboratory animals; Mice; Animals, Laboratory; Mice. HISTOLOGY i6i between the parenchymatous elements. The appearance of the epithehal cells of the alveoli is not uniform, indicating different phases of secretory activity. In some cells the nucleus is in the middle of the cell and the cyto- plasm is homogeneous. In others the cytoplasm appears foamy or contains large protruding fat droplets. If the litter is small and all the nipples are not suckled, some of the glands may undergo partial regression while others are still functioning (16,35). The young mice usually suckle for about 21-23 days. Thelength of the suckling period depends somewhat on the size of the litter, large ^jjg. ;^l-g^'»'"'««^'^ ^. Fig. 86.—Mammary gland 24 hours after lactation stopped. for 22 days. (X 100.) Lactation had continued litters usually suckling longer than small litters. About three weeks after parturition the glands begin to show signs of regression. Twenty-four hours after suckling ceases, milk has accumulated in the ducts and alveoli, which are distended. Epithelial cells have become detached and are lying loose in the lumen. These degenerate, the cytoplasm becoming swollen and the pyknotic nuclei fragmenting (Fig. 86). In some epithelial cells the swollen cytoplasm forms globules which are discharged into the lumen, but the nuclei with small amounts of cytoplasm remain intact. The shrunken alveoli lose their close contact with the capillaries. The lack, of blood supply hastens the process of regression. During this process the space between the shrinking alveoli is being filled by adipose cells. Some of these cells seem to develop from fibroblasts which are in. 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 Roscoe B. Jackson Memorial Laboratory; Little,
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Keywords: ., boo, bookcentury1900, bookcollectionbiodiversity, booksubjectmice
