Flashcards in SDR Deck (34):
When does differentiation begin?
What does the presence of testis-determining factor cause and where is it located? (+SRY)
-Gonads develop into a testis
-Located on the Y chromosome
What does the absence of testis-determining factor cause? (-SRY)
-Gonad differentiates into an ovary
What are the different but related ducts that form beside the undifferentiated gonads?
Explain what happens in the presence of SRY (+SRY)
-The Y chromosome carries the SRY gene
-Gonads differentiate into testes
-The presence of testosterone causes the wolfian ducts to develop into the internal male structures
-The presence of anti-mullerian hormone causes degeneration and atrophy of mullerian ducts
What are the internal male structures that develop?
Explain what happens in the absence of SRY (-SRY)
- Gonads differentiate into ovaries
- The absence of testosterone causes degeneration and atrophy of the wolfian duct
-The absence of the anti-mullerian hormone allows for mullerian ducts to develop into the internal female structures
What are the internal female structures that develop?
Upper part of the vagina
Describe the process of puberty:
-Pulsatile release of GnRH followed by an increase in LH and FSH ->Results in episodic peaks of estradiol and testosterone-> Initiates secondary sexual maturation in girls and boys
- No secondary sex characteristics; in females by 13 and males by 14
-Etiology: undernutrition, athletics, HPG defects, stress, environmental exposures
-95% of the time: normal hormone levels, HPG axis intact, maturation just slow.
- Sexual maturation before ages 6-7 in females and 9 in boys
-Central: GnRH-dependent-short stature d/t premature closing of the epiphysis
-Peripheral: GnRH independent- gonadal tumors, testotoxicosis, exposure to exogenous sex steroids
What are the male sex hormones (4) and what do they do?
1. GnRH- released from hypothalmus, stimulates the anterior pituitary to secrete FSH and LH
2. FSH- stimulates spermatogenesis (Sertoli cells)
2. LH- stimulates the secretion of testosterone (Leydig cells)
3. Testosterone- stimulates spermatogenesis, stimulates the development of male secondary sex characteristics
Describe hormonal regulation of the hypothalmus-pituitary-testes axis (?)
The hypothalamus releases GhRH which stimulates the anterior to release FSH and LH. LH stimulates the Leydig cells to secrete testosterone which stimulates spermatogenesis and secondary sex characteristics. FSH (and testosterone) stimulate the Sertoli cell which leads to spermatogenesis.
**Testosterone provides negative feedback to hypothalamus= if too high will not produces more GnRH.
**Inhibin works to inhibit FSH release from the ant. pit
Outline the Uterine Cycle (aka Menstrual Cycle)
1. Menstrual phase: bleeding. Day 1 to day 3-5; function layer of the endometrial lining and blood leave the uterus through the vagina
2. Proliferative phase (follicular)- Begins at end of menstruation; repair and growth of inner endometrial lining
3. Secretory phase (luteal)- Due to secretion of progesterone by the corpus luteum= causes endometrial lining to thicken (forming nutritious environment awaiting the arrival of a fertilized ovum)
What hormone is the follicular phase dominated by?
Hypothalamus secretes GnRH->gonadotropin release by ant pit gland-> FSH and small amounts of LH stimulate growth and maturation of the ovarian follicle-> maturing ovarian follicle secretes large amounts of estrogen-> estrogen aids in maturation of follicle and builds lining -> ends with sharp rise of LH which causes ovulation.
What hormone is the luteal phase dominated by?
Follicular cells of the ruptured follicle on the surface of the ovary form the corpus luteum
LH stimulates the corpus luteum to secrete progesterone and small amounts of estrogen-> progesterone and estrogen exert a negative feedback effect on the ant pit gland-> inhibiting FSH and LH
Progesterone supports the endometrial lining of the uterus during the second half of the cycle
When corpus luteum dies, secretion of progesterone and estrogen decline -> FSH and LH are once again secreted and cycle repeats
What is the corpus luteum?
During the luteal phase, the site of the ruptured/old follicle becomes the corpus luteum which secretes estrogen and progesterone. These hormones stimulate continued thickening of the endometrium. Cells of the corpus luteum become enlarged and fatty. If pregnancy does not occur the corpus luteum begins to degenerate and estrogen and progesterone levels fall.
If fertilization dose occur what supports the corpus luteum?
Describe the positive feedback loop of menstruation.
Hypothalamus release GnRH-> ant pit release LH stimulating the Theca cells to produce androgens to stimulate Granulosa cells which are also stimulated by FSH -> estrogen production-> loops back to hypothalmus to continue to release GnRH= spike in FSH and LH causing ovulation
Describe the negative feedback loop happening in menstruation.
Hypothalamus releases GnRH->ant pit releases LH to stimulate theca cell to produce androgen which stimulates the Granulosa cell which is also stimulated by FSH-> estrogen and progesterone production. When estrogen and progesterone increases, hypothalamus slows production of GnRH.
Inhibin also plays part in decreasing LH and FSH from ant pit.
Failure of menarche and the absence of menstruation by age 14; without development of secondary sex characteristics by age 16
Absence of menstruation for a time equivalent to 3+cycles or 6 months in women who have previously menstrated
What is the primary hormone problem with PCOS?
FSH low and LH elevated
Disruption in H-P-G axis:
What is the leading cause of infertility?
Polycystic Ovarian Syndrome
T/F: Hyperinsulinemia causes an increase in severity of symptoms of PCOS
T/F: Polycystic ovaries are a requirement for diagnosis of PCOS
What are some common culprits of pelvic pain?
- Pelvic inflammatory disease
-Leiomyomas (uterine fibroids)
Causes of endometriosis (4 theories).
1. Regurgitation through fallopian tubes; during retrograde menstruation some of the endometrial cells relfux up the fallopian tube and reimplant ectoptically
2. Lymphatic dissemination; transport of endometrial cells throughout the lymphatics
3. Extrapelvic dissemination through pelvic veins
4. Metaplastic differentiation of epithelial cells= turn into endometrial cells
What is endometriosis?
Endometriosis is the presence of endometrial tissue outside the lining of the uterine cavity
Classic symptoms of endometriosis:
Abnormal uterine bleeding
Begins 5 to 7 days before menses, peaks, and lasts for 2 to 3 days
Severity does not reflect extent of disease
Cervical cancer is related to:
R/t prenatal exposure to diethylstilbestrol
May also be caused by:
Spread of cervical cancer
Human papillomavirus infection
Chronic local irritation
Good prognosis, bleeding is an early symptom in post menopausal women, removal of uterus can be curative