SUPRARENAL GLANDS. 



33 1 



Blood vessels enter the breast from several sources and form capil- 

 laries around the alveoli. Lymphatic vessels are found in the areola, 

 around the sinuses, and in the interlobular tissue. The collecting vessels 

 pass chiefly toward the axilla; a few penetrate the intercostal spaces 

 toward the sternum. The nerves are like those of sweat glands. 



SUPRARENAL GLANDS. 



The suprarenal glands are two flattened masses of strands of cells, 

 without lumen or ducts, situated in the retroperitoneal tissue above the 

 kidneys. The right is generally described as triangular and the left as 

 crescentic. They are between one and two inches long, not quite so wide, 

 and about a quarter of an inch thick. On section they 

 present macroscopically a yellowish cortical substance 

 which becomes dark brown toward the center of 

 the gland. In the thicker portions there is a vascu- 

 lar medullary substance also dark colored, related to 

 the cortex as seen in Fig. 386. In many lobes the 

 medulla is lacking so that the deep portions of the 

 cortex of the two sides are in contact. The supra- 

 renal glands produce a secretion received by 

 the blood (some have said by the lymphatic ves- 

 sels also). Death follows the removal of the 

 glands, and their pathological conditions may be 

 fatal. Intravenous injection of suprarenal extract 

 causes a great rise in blood pressure. 



The development of the suprarenal gland indi- 

 cates a radical difference between the cortex and 



medulla. In the sharks these components form separate organs. The 

 interrenal gland which corresponds with the cortex, consists of cords 

 of mesodermal cells and has apparently a sinusoidal circulation. The 

 medulla is represented by a peculiar development of the sympathetic 

 ganglia. In mammals the medulla likewise arises by the development 

 of chromaffine cells in relation with the sympathetic nerves. The posi- 

 tion of the involved nerves, between the aorta and the Wolman body, 

 is shown in Fig. 276, C, page 245. The sympathetic portion of the 

 gland becomes surrounded by dense mesenchyma in which the cords of the 

 cortex are differentiated. Opinions are divided as to whether this mesen- 

 chyma is derived from the Wolffian body or from the coelomic epithelium. 

 As the kidneys attain their permanent position the suprarenal glands are 

 found above them; they are structurally as independent of the kidneys as 

 are the liver and spleen. 



Cortex. Medulla. Vein. 



FIG. 386. SECTION" OF THE 

 SUPRARENAL BODY OF 

 A CHILD. X 15- 



