ACTIVITIES OF THE OVARY 



89 



The culmination of these changes in behavior, resulting in a receptive attitude 

 toward the male, is reached at about the time when the egg is discharged 

 from the ovary in many mammalian species. In certain other mammals the 

 period of heat may precede the ovulatory phenomena. 



5) Effects of Estrogen in Other Vertebrates. In the hen, estrogenic hor- 

 mone causes enlargement and functional activity of the oviduct. Estrogenic 

 substance, when injected into female chicks from the eighteenth to the fortieth 

 day, causes an enlargement of the oviduct to about 48 times the natural size. 

 Estrogen also has a profound effect upon the activities of the full-grown hen 

 and aids in egg production (Romanoff and Romanoff, '49; Herrick, '44). 

 Estrogen has a pronounced effect upon the oviducts of other vertebrate forms. 



b. Progesterone — The Hormone of the Corpus Luteum 

 1) Production of Progesterone. The luteinizing hormone, LH, of the an- 

 terior lobe of the pituitary gland is concerned not only with the development 



Fig. 52. Characteristic histological changes in the female reproductive tract under the 

 influence of estrogen and progesterone. (A-C) Vaginal cyclic changes in the rat. In 

 (A) is shown the condition of the vaginal wall in the diestrus (resting) condition; (B) 

 shows changes in vaginal wail structure during estrus. Observe cornification of outer layer 

 of cells; (C) shows vaginal wall tissue immediately following estrus, i.e., during metestrus. 

 The presence of progesterone tends to suppress the action of estrogen. (After Turner: 

 General Endocrinology, Philadelphia, Saunders.) (D, E) Cyclic changes of the Fallo- 

 pian tube of the human female during the reproductive cycle. In (D) is shown the mid- 

 interval of the cycle, i.e., at a time paralleling estrus in mammals in general: (E) shows 

 the cellular condition of the lining tissue of the Fallopian tube just before menstruation. 

 In (D) the tissue has responded to the presence of estrogen; (E) effect of progesterone 

 is shown. (After Maximow and Bloom: A Textbook of flistology, Philadelphia, Saunders.) 

 (F, G) Cyclic changes in the uterine-wall tissue during the reproductive cycle in the 

 human female. In (F) is shown general character of the uterine wall during the follicular 

 phase, i.e., responses to estrogen; (G) shows the general condition of the uterine wall 

 following ovulation. The uterus is now responding to the presence of progesterone added 

 to the follicular or estrogenic stimulation. (After Maximow and Bloom: A Textbook of 

 Histology, Philadelphia, Saunders.) 



