Lecture outline I. Puberty & Development of Secondary Sexual Characteristics A. Establishing the ovarian cycle B. Breast development C. Pubic and Axillary Hair growth II. Human Reproductive Anatomy A. Pelvic Girdle B. External Genitalia C. Uterus, Ovaries & Oviducts D. Breasts III. Gender Differences: an anatomical perspective A. Male Reproductive Tract

Puberty & Development of Secondary Sexual Characteristics Puberty Hormones involved in regulating changes involved with puberty

Endocrine organs involved in sex development:

Hypothalamus & Pituitary: Hypothalamus secretes GnRH (gonadotropin releasing hormone), which in turn regulates the Pituitary gland. GnRH is secreted through a complex of veins routed directly to the Once at anterior portion of pituitary, GnRH FSH (Follicle stimulating hormone) Estrogen acts as positive feedback to regulate hypothalamus to stimulate production of GnRH, which triggers increased LH LH (Leutenizing hormone)

Ovaries & estrogen secretion 3 major estrogens secreted 1) Estradiol 2) Estrone 3) Estriol

Estradiol Breast development and maintenance Adding fat to breasts, hips, thighs during puberty Improving bone strength and density Accelerating bone maturation and bringing epiphyses to closure, completing growth Growth of the uterus Development of the endometrial lining to a thickness necessary to support pregnancy and menstruation Thinning of cervical mucus at ovulation Promoting and maintaining vaginal mucosal thickness and secretions Serving as the primary feedback to the brain of sex hormone levels in both males and females. Participating in triggering ovulation Preservation of egg cells Enabling spermatogenesis Effect on lipids Vascular effects Cerebral effects

A. Establishing the ovarian cycle- Gonadotropins trigger changes: From birth to puberty, the gonads secrete Estrogens inhibit the As the brain matures, the hypothalamus begins to override the negative feedback and begins GnRH secretion GnRH stimulates the anterior pituitary to release FSH & LH Adult cyclic pattern achieved & hormonal interactions stabilize – events heralded by

B. Breast development Mammary glands = Thelarche (breast development) occurs as a result of the increased estrogen levels

Tanner’s 5 stages of breast development (based on Caucasian girls)

C. Pubic and Axillary Hair growth Andrenarche = Pubarche = In most girls, pubic hair first appears along the edges of the labia majora, and spreads forward over the next 2 years.labia  By 3 years into puberty, the pubic triangle is densely filled.  Within another 2 years pubic hair also grows from the near thighs in most young women, and sometimes a small amount up the line of the abdomen toward the umbilicus.

II. Adult Female Anatomy A. External Genitalia B. Uterus, Ovaries & Oviducts C. Breasts

A. External Genitalia

Shaft contains 2 corpora cavernosa consisting of erectile tissue.

B. Uterus, Ovaries & Oviducts 1)Uterus: Cervix: External Os – Internal Os – Endocervical canal – Endocervical glands

The cervix convulses during orgasm and the external os dilates in order to facilitate the transfer of semen from vagina into the uterus.

Positions of uterus The uterus is very mobile and its position between the rectum and bladder varies depending on posture, how full the bladder or rectum is, and # of children borne

2) Ovaries & Oviducts

C. Breasts

A fat-tailed dunnart with young attached to her teats

III. Gender Differences: an anatomical perspective

A. Male Reproductive Tract

B. Skeletal differences Os coxae

1. Female v. Male Pelvis Anthropiod & android pelvis more common in males

Position of reproductive organs within the pelvic girdle

2. Angle of pelvic tilt

3. Q-angle differences