A Cytological Study of the Alimentary Tract of the Domestic Fowl Gallus Domesticus

Abstract

1. Proventriculus The Golgi material of all the gastric cells, except the zymogenic cells, is situated between the nucleus and the lumen of the gland. In the zymogenic cells it always lies at the level of the bottom of the intercellular clefts. The apparent reversal of the polarity of the Golgi material of the zymogenic cells is due to the movement of the nucleus. The mitochondria of the surface epithelium and the mucous neck cells are very delicate filaments. In the zymogenic cells thick rods and granules are usual. The functional stage is characterized by the presence of long rods with marked polar orientation. Secretory granules arise in close association with the Golgi material of all the gastric cells. Feeding accelerates the evacuation of secretion and immediately stimulates new production. A total expulsion of secretory granules never takes place in any of the gastric cells. 2. Gizzard The keratinoid material is a secretory product. The Golgi material does not undergo any changes after feeding. The secretory process is very slow and is independent of digestion. Secretion terminates with the degeneration and ultimate death of the cell. 3. Intestinal epithelium The Golgi material of the epithelial cells lies above the nucleus. It shows marked changes of morphological and physico-chemical nature as soon as the resting cell is stimulated by direct contact with food. The mitochondria are in the form of filaments, rods, and granules. Their polar arrangement is a constant feature. When the cell is first stimulated by food, the mitochondria stain very faintly. Secretory granules arise in close association with the Golgi material; they move towards the glandular pole of the cell. Morphological changes of the Golgi material and mitochondria diminish and finally disappear in the posterior parts of the alimentary tract. 4. Goblet cells The Golgi material lies above the nucleus. During secretory activity it enlarges greatly; it decreases in mass during the final stage of secretion. The mitochondria are in the form of filaments, rods, and granules. With, the accumulation of secretory material, the mitochondria collect on the border of the mucous mass and in the cytoplasm of the narrow part of the cell. Secretory granules arise in close association with the Golgi material. The secretory process of these cells is autonomous and is not directly correlated with digestion.