sex & hormones

• Androgens


  • Hormones more abundant in males, increase growth of testes, cause development of seminal vesicles and vas deferens from Wolffian ducts
• Estrogens


  • Hormones more abundant in females, responsible for female sexual development and function, including estradiol
• Oxytocin


  • Stimulates contractions of the uterus during the delivery of a baby and stimulates the mammary gland to release milk
• Sensitive Period


  • When hormones determine whether an embryo develops a male or female anatomy
• LH (Luteinizing hormone)


  • Produced by the anterior pituitary gland, triggers ovulation in females and stimulates testosterone production in males
• Steroid Hormones


  • Class of hormones derived from cholesterol, including cortisol, aldosterone, estrogen, progesterone, and testosterone, among others
• Testosterone


  • Primary male sex hormone responsible for male sexual development, function, and characteristics
• Müllerian Ducts


  • Precursors to female internal structures
• Organizing effects


  • Produce long-lasting structural effects, most prominent during a sensitive stage of early development
• Periovulatory Period


  • Time around ovulation during the menstrual cycle when the ovum is released from the ovary and available for fertilization
• During the early sensitive period in immature mammals, a protein called alpha-fetoprotein is present, absent in adults. In rodents, alpha-fetoprotein binds with estradiol, preventing its entry into cells and inhibiting masculinizing effects
• Impotence is the inability to achieve or maintain an erection sufficient for sexual intercourse, often due to physical or psychological factors
• Male’s Y chromosome


  • Includes the SRY gene, causing primitive gonads to develop into testes
• FSH (Follicle-stimulating hormone)


  • Produced by the anterior pituitary gland, stimulates the growth of ovarian follicles in females and spermatogenesis in males
• Ovaries


  • Female gonads responsible for producing eggs (ova) and sex hormones, including estrogen and progesterone
• Activating effects


  • More temporary effects when a hormone increases some activity that lasts only while the hormone is present, can occur at any time in life
• Progesterone


  • Hormone involved in the menstrual cycle and pregnancy, regulating the uterine lining and supporting gestation
• Estradiol


  • The most potent naturally occurring estrogen in humans, playing a key role in the menstrual cycle and the development of secondary sexual characteristics in females
• Menstrual Cycle


  • Regular natural cycle of changes in the female reproductive system, involving menstruation, follicular development, ovulation, and corpus luteum formation
• Testes


  • Male gonad responsible for sperm production and hormone secretion, including testosterone
• Sexually Dimorphic Nucleus


  • One area in the anterior hypothalamus, larger in males than in females, contributes to control of male sexual behavior
• Wolffian Ducts - Precursors to male internal structures