Henry Gray (18251861). Anatomy of the Human Body. 1918.
has also discovered, in the lymph issuing from the thymus, similar cells to those found in the gland, and, like them, containing hemoglobin in the form of either granules or masses. From these facts he arrives at the conclusion that the gland is one source of the colored blood corpuscles. More recently Schaffer has observed actual nucleated red-blood corpuscles in the thymus. The function of the thymus is obscure. It seems to furnish during the period of growth an internal secretion concerned with some phases of body metabolism, especially that of the sexual glands.
Vessels and Nerves.The arteries supplying the thymus are derived from the internal mammary, and from the superior and inferior thyroids. The veins end in the left innominate vein, and in the thyroid veins. The lymphatics are described on page 698. The nerves are exceedingly minute; they are derived from the vagi and sympathetic. Branches from the descendens hypoglossi and phrenic reach the investing capsule, but do not penetrate into the substance of the gland.
4d. The Hypophysis Cerebri
The hypophysis (pituitary body) (Fig. 1180) is a small reddish-gray body, about 1 cm. in diameter, attached to the end of the infundibulum of the brain and resting in the hypophyseal fossa.
FIG. 1180 The hypophysis cerebri in position. Shown in sagittal section. (See enlarged image)
FIG. 1181 Median sagittal through the hypophysis of an adult monkey. Semidiagrammatic. (Herring.) (See enlarged image)
The hypophysis consists of an anterior and a posterior lobe, which differ from one another in their mode of development and in their structure (Fig. 1181). The anterior lobe is the larger and is somewhat kidney-shaped, the concavity being directed backward and embracing the posterior lobe. It consists of a pars anterior