1. Major endocrine glands

2. The Hypothalamus Small structure at the base of the brain Regulates many body functions, including appetite and body temperature Regulates the pituitary gland

3. The Pituitary Gland  A sort of master gland  It is a cherry-sized endocrine gland  The hormones it secretes affect the growth and secretion of other endocrine glands  The real boss is the hypothalamus

4.  Embryologically distinct  Release different hormones – Anterior Pituitary releases Luteinizing hormone and growth hormone – Posterior Pituitary releases Oxytocin Anterior and Posterior Pituitary

5. Pancreas  Both endocrine (hormones) and exocrine (enzymes) tissue  Releases the hormone insulin

6. The Adrenal Glands  A pair of endocrine glands just above the kidneys  They secrete epinephrine and norepinephrine  In common with the pituitary, adrenals are two glands with distinct embryological origins. –Adrenal medulla –Adrenal cortex  Both parts of the adrenals work together to regulate metabolism and cope with stress.

7. Sex Hormones Sex hormones are secreted by the gonads and by the adrenal glands Androgens Masculinizing hormones Estrogens Feminizing hormones

8. Gonads: Testes  Male gonads  Two functions –Steroidogenic –Gametogenic

9. Primary Testicular Hormones  Steroid Hormones –Androgens

10. Biosynthesis Of human steroid Hormones

11. What is the action of testosterone

12. Testosterone (notes) Source synthesized & released by Leydig (interstitial) cells of testis release stimulated by LH Actions inhibits release of GnRH & LH (not FSH) stimulates spermatogenesis (in conjunction with FSH) stimulates differentiation of male genitalia (in utero) stimulates development of male 2nd sexual characteristics at puberty growth & development of internal/external genitalia bone growth and epiphyseal plate closure, muscle development axillary, pubic, body hair, male pattern baldness fat distribution, laryngeal growth, sebaceous glands behavioral effects, libido, aggression Mechanism: steroid, androgen binding protein,  transcription,  translation Glycolysis , fatty acid synthesis , mineral deposition and bone growth 

13. In most mammals, males are more aggressive, and castration reduces aggressive behavior. Inter-male and territorial aggression increase after puberty. After a fight, the winner has higher, the looser lower levels of testosterone. Criminals: Age at first violent offense correlates with testosterone levels. Violent women prisoners have higher testosterone levels than non-violent ones. TESTOSTERONE and AGGRESSION

14. Testosterone and Marriage

15. Gonads: Ovaries  Female gonads  Two compartments –Steroidogenic –Gametogenic  Cyclic in function  Hormones associated with gamete maturation were co-opted over evolutionary time to regulate sexual behaviors.

16. Primary Ovarian Hormones  Steroid Hormones –Estrogens –Progesterone Follicular cells, corpus luteum, placenta, adrenal gland

17. Follicular development

18. Estrogens synthesis by granulosa & thecal cells Note: “estrogens” are a mixture of estradiol (most), estriol, & estrone LHFSH Note: LH & FSH are shown as acting on the wrong cells in your text book

20. Estrogen actions moderate increase inhibits release of GnRH & LH (negative feedback) large increase stimulates LH release (positive feedback) differentiation of female genitalia in utero is due to the absence of testosterone, not any actions of estrogens stimulates the changes seen at puberty growth of external genitalia growth of breasts (particularly fat deposition & duct growth) bone growth & epiphyseal plate closure (pubertal spurt & female configuration) fat distribution, reduces LDL & raises HDL (anti-atherogenic) during menstrual cycle  Fallopian tube peristalsis & ciliary activity, growth of myometrium & endometrium, cervical mucus abundant & clear Lipogenesis, transcription and translation, Lipogenesis , transcription and  translation ,

21. Progesterone actions high levels (in presence of estrogen) inhibit release of GnRH, hence LH & FSH (negative feedback) stimulates the changes seen at puberty growth of breasts (particularly glandular tissue) during menstrual cycle  Fallopian tube peristalsis & myometrial contractions  endometrial blood flow,  coiling of glands,  glycogen content  thick sticky cervical secretion (mucus plug)  body temperature by ~0.5  C Note: adrenal androgens stimulate axillary & pubic hair growth, libido Essentially required for the implantation of fertilized ovum and maintenance of pregnancy

22. Follicular life cycle through menstrual cycle fig 17-17

23. Estrogens synthesis by granulosa & thecal cells fig 17-19 Note: “estrogens” are a mixture of estradiol (most), estriol, & estrone LHFSH Note: LH & FSH are shown as acting on the wrong cells in your text book

24. Implantation of blastocyst fig 17-24

25. Sequential hormonal changes during menstrual cycle 1.degeneration of corpus luteum  estrogen,  progesterone,  inhibin  FSH & LH 2.antral follicles develop  estrogen levels 3.plasma estrogen levels increase 4.~day 7, dominant follicle secretes high levels of estrogen 5.plasma estrogen level increases sharply 6.high estrogen levels suppress FSH levels causing degeneration of non-dominant follicles 7/8.  estrogen levels  LH surge (positive feedback) 9.1 st meiotic division of 1  oocyte 10.~day 14, ovulation occurs 11.the dominant follicle collapses, and reorgranizes as the corpus luteum

26. Sequential hormonal changes during menstrual cycle 12.corpus luteum secretes estrogen & progesterone 13.plasma levels of estrogen & progesterone increase, suppressing release of GnRH, LH, & FSH 14.~day 25, corpus luteum spontaneously degenerates 15.  secretion & plasma levels of estrogen & progesterone 16.  estrogen & progesterone  FSH & LH levels which begin follicular development of the next menstrual cycle

27. Hormonal interactions in the female fig 17-20

28. Hormonal initiation of ovulation fig 17-21

29. Endometrial changes during menstrual cycle fig 17-22