BRS Flashcards
The testes of the gonadal males secrete _1_hormone that which causes atrophy of 2 duct. Testosterone stimulates the growth and differentiation of 3 duct which develops into the male internal genital tract.
- antimullerian hormone (AMH)
- Wolffian duct
- Mullerian duct
Testosterone is the major androgen synthesized and secreted by the _ cells.
Leydig
Laydig cells do not contain which steroid synthesis enzymes and thus cannot produce glucocorticoids and mineralocorticoids.
21beta-hydroxylase and 11beta hydroxylase
Accessory sex organs like the prostate has _ which can convert testosterone to its active form.
5a-reductase
Finasteride is a _ that which can be used to treat benign prostatic hyperplasia becuase they block the activation of _ to _ in the prostate.
- 5a-reductase
FSH acts on what cells to maintain spermatogenesis?
Sertoli cells.
Sertoli cells produces what substance that which negative feedback to inhibit FSH secretion?
inhibin
True or False. Testosterone has negative feedback inhibitory affects on both the anterior pituitary and hypothalamus.
True
Explain what happens in androgen insensitivity disorder (testicular feminizing syndrome).
- caused by deficiency of androgen receptors in target tisues of males.
- The actions of T and DHE re absent
- Female external genitalia and no internal genital tract
- T levels are elevated due to lack of receptors in anterior pituitary (lack of feedback inhibition)
what are the actions of T in sexual development?
- differentiation of epididymis, vas deferens, and seminal vesicles
- pubertal growth spurt
- cessation of pubertal growth spurt (epiphyseal closure)
- libido
- spermatogenesis in sertoli cells (paracrine effects0
- deepening of voice
- increased muscle mass
- growth of penis and seminal vesicles
- negative feedback on anterior pituitary
what are actions of dihydrotestosterone?
- differentation of penis, scrotum, and prostate
- male hair pattern
- male pattern bladness
- sebaceous gland activity
- growth of prostate
Puberty onset is initiate by pulsatile release of what hormone?
GnRH which in turn releaes FSH and LH in a pulsatile fashion.
In childhood both FSH and LH are lowest, but one of them exists in greater quantity than the other. WHich one?
FSH
During puberty, both FSH and LH increase, which one of them exists in greater quantity?
LH
Explain how estrogen and progesterone is synthesized in the ovary..
Theca cells produce testosterone. Androstenedione diffuses to the nearly granulosa cells, which contain 17beta-hydroxysteroid dehydrogenase, which converts androstenedione to testoserone, and aromatase, which converts testosterone to 17beta-estradiol (stimulated by FSH)
FSH and LH stimulate what processes in the ovaries?
- steroidogenesis in the ovarian follicle and corpus leuteum
- follicular development beyond the antral stage
- ovulation
- luteinuzation
What are the actions of estrogen in the female reproductive system?
- Negative feedback and positive feedback effects on FSH and LH secretion
- Causes maturation and maintenance of the fallopian tubes, uterus, cervix and vagina
- causes the development of female secondary sex characteristics at puberty
- causes development of the breasts
- Up regulates estrogen LH and progesterone receptors
- Causes proliferation and development of ovarian granulosa cells
- maintenance of pregnancy
- lowers the uterine threshold to contractile stimuli during pregnancy
- stimulates prolactin secretion (but then blocks its action on the breast)
what are the actions of progesterone?
- has negative feedback effects on FSH and LH secretion during luteal phase.
- maintains secretory activty of the uterus during luteal phase
- maintenance of pregnancy
- raises the uterine threshold to contractile stimulai during pregnancy
- participates in development of the breasts.
Generally what happens during the follicular phase to the following: primordial follicle, LH and FSH receptors, Estradiol levels, FSH and LH levels and progesterone levels.
Follicular phase is Days 0-14.
- A primordial follicle develops to the graafian stage with atresia of the neighboring follicles
- LH and FSH receptors are up regulated in theca and granulosa cells
- Estradiol levels increase and cause proliferation of uterus
- FSH and LH levels are suppressed by the negative feedback effect of estradiol on the AP
- progesterone levels are low.
Explain what happens ovulation.
Ovulation is day 14 before menses, regardless of cycle length. Thus, in a 28-day cycle, ovulation occurs on day 14; in 35-day cycle, ovulation occurs on day 22.
- A burst of estradiol synthesis has a positive feedback at the end of the follicular phase on secretion of FSH and LH (LH surge)
-Ovulation occurs as a result of the estrogen-induced LH surge
estrogen levels decrease just after ovulation (but rise again during the luteal phase).
-Cervical mucus increases in quantity; it becomes less viscous and more penetrable by sperm
