THE ENDOCRINAL ORGANS 



327 



relation between follicular secretion and menstruation is demonstrated 

 by the fact that menstruation follows the discharge of the follicular 

 secretion and ceases when the ovaries are removed. 



The follicular hormone, theelin, has the chemical formula C18H24O3 

 and is a fatty substance, soluble in alcohol and other hpoid solvents. 

 It is used hypodermically to induce puberty and menstruation. 



One of the names for the hormone of the corpus luteum is progestin. 

 Its action is antagonistic in some effects to that of theelin, for, while theelin 

 acts as a sex stimulant, progestin prepares the uterus for the reception 

 of the ovum. 



Suprarenal Glands. The suprarenals or adrenals of man are two small 

 glands, each averaging only four to five grams in weight, and each, as the 



HEP. PORTAL V 



BILE DUCT 



R. SUPRARENAL VES 



.ESOPHAGUS 



L INF PHRENIC A. 



DORSAL AORTA 



R. RENAL VES 

 R. KIDNEY 

 VENA CAVA 



LEFT SUPRARENAL GLAND 



L. KIDNEY 



-L SUPRARENAL VES 

 .^=1.. RENAL VESSELS 



SUP MESENTERIC A. 



Up „, ^_ up^T£(, 



SPERMATIC COVARIAN) VES'/ SnF. MESE^^■ER!C A 



Fig. 291. — Shows the suprarenals in relation to the kidneys as seen when the fat 

 which normally encloses them is removed. The relations of the blood vessels which 

 supply them are also shown. 



names suggest, lying like a cap upon the upper end of a kidney, embedded 

 usually in the same mass of fat. Accessory adrenals also occur not 

 infrequently near the kidneys or the gonads. 



The adrenal gland has a rich blood supply. Arterial blood comes from 

 three sources, phrenic, aortic, and renal vessels. The gland is drained by 

 the right and left suprarenal veins, the former connected with the post- 

 cava, the latter with the left renal. Lymphatic vessels are abundant. 



An adrenal has two kinds of tissue, an outer yellowish cortex and an 

 inner brownish medulla. The central or medullary portion of the adrenal 

 is characterized by relatively large "chromaffin" cells, so-called because 

 they have a strong affinity for chromic salts which stain them brown. 

 They are arranged in clusters separated by numerous lacunar blood 

 spaces. A compact connective-tissue capsule encloses the glandular 

 tissues. (Fig. 292) 



The adrenals have a double function corresponding with their histo- 

 logical differentiation into two tissues. The cortex secretes an endocrine, 



