. Principes de la science vétérinaire ; un texte-livre pour une utilisation dans les écoles agricoles. La médecine vétérinaire. Le système digestif de surface 89 lobes distincts qui sont divisés en portions plus petites appelées lobules. Un conduit de transmettre le produit loin de la glande est habituellement présent. Le conduit se connecte à l'interne avec les alvéoles de la glande, les récipients dans lesquels les cellules sécrétrices de s'acquitter de leurs fluides. Vaisseaux sanguins d'encercler les alvéoles et l'offre de la lymphe à réparer le préjudice causé par l'activité des cellules (Fig. 28). Nerfs sécréteurs spéciaux sont fournis pour influencer l'activité fonctionnelle. Les

• Contributeur: The Book Worm / Alamy Banque D'Images
• ID de l’image: RDW53P
• Taille du fichier: 7,1 MB (303,1 KB Téléchargement compressé)
• Autorisations: Modèle - non | Propriété - non
• Dimensions: 1123 x 2225 px | 19 x 37,7 cm | 7,5 x 14,8 inches | 150dpi

Informations supplémentaires

Cette image appartient au domaine public, ce qui signifie que le droit d’auteur a expiré ou que le titulaire du droit d’auteur a renoncé à ses droits. Les frais facturés par Alamy couvrent l’accès à la copie haute résolution de l’image.

Cette image peut avoir des imperfections car il s’agit d’une image historique ou de reportage.

. Principles of veterinary science; a text-book for use in agricultural schools. Veterinary medicine. THE DIGESTIVE SYSTEM 89 surface distinct lobes which are subdivided into smaller portions called lobules. A duct to convey away the product of the gland is usually present. The duct connects internally with the gland alveoli, the receptacles into which the secretory cells discharge their fluid. Blood-vessels encircle the alveoli and supply lymph to make good the loss caused by the activity of the cells (Fig. 28). Special secretory nerves are provided to influence functional activity. Secretory products are of various kinds and for many different purposes. They are fluid in character and act in a chemical manner. Among the most familiar secretions are the saliva and the gastric juice. The^ process of secretion is inter- mittent, periods of rest occurring in the work of glands as in all other organs. During the rest period the protoplasm of gland-cells becomes loaded with small granules that are the stored elements, from which the organic constituents of the secretory product are manufactured. As secretion goes on these granules gradually disappear. If it is continued for some hours, they disappear com- pletely. If the process of secretion were a mere filtration from the blood through cells , into gland alveoli, as was at one time believed, we should expect to find the same amount of soluble, diffusible salts in the secretion as in the blood. Take the saliva as a typical secretion to illus- trate the point. It contains only half the amount of diffusible salts as the blood, which makes it clear that the gland-cells must prevent diffusion of the balance. Further- more, by hindering the outflow of saliva from a duct, the pres- sure will rise above that of the blood in the blood-vessels which. Fig. 28.—The principle of glandular structure. In the upper figure a simple microscopic gland has been laid open by cutting through its vertical axis. The cells are seen to surroun

Recherche dans la banque de photos par tags

• bookcentury1900
• bookdecade1920
• booksubjectveterin
• bookyear1920