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60 Cards in this Set

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  • Back
What are time intervals of GnRH pulsativity in FEMALES?
Follicular phase - 60 - 90 minutes.

Luteal phase - 100-2126 minutes.
What is the pulsativity frequency in MALES
90-120 minutes.
What is the relevance of PULSATIVITY in GnRH release.
Continuous release would result in receptor DOWNREGULATION.
What is the half-life of GnRH
2-4 minutes.
What protein unit do FSH, LH, hCG, and TSH all share in common?

FSH maintains function of corpus luteum?

LH maintains corpus luteum. (Thecal lutein cells and follicular lutein cells secrete hormomes POST-OVULATION from corpus luteum)
What cells produce INHIBIN in MEN and WOMEN?
MEN = Sertoli

WOMEN = Granulosa
What is the pathway from CHOLESTEROL to DHT and estradiol
CHOLESTEROL --> Pregnenolone --> Progesterone --> Testosterone --> 1) DHT (via 5-a reductase) and 2) estradiol (via aromatase)
What effect does estrogen have on FSH/LH/GnRH?
Estrogen decreases ALL THREE. However, estrogen MAY increase LH
What effect does progesterone have on FSH/LH/GnRH?
Decreases ALL THREE.

PRODUCED BY FOLLICULAR LUTEIN CELLS. (luteinized follicular/granulosa cells)
What is testosterone's role in LH and GnRH?
Decreases in BOTH
Where is DHT primarily producted
When do germ cells begin to differentiate?
By week 8. Remember that at week 7, still undifferentiated embryo.
When is the maximum number of oocytes attained?

What stage are the oocytes in? What cells are the oocytes composed of?
MAX at week 20 (gestational): 6-7 million oocytes

Primary oocytes have single layer of GRANULOSA cells attached to a basement membrane.
What male repro tract organs arise from UROGENITAL SINUS?
Prostate and prostatic urethra. Prostate is an endodermal invagination of urethra.
What stimulates Wollfian duct development?
What suppresses the development of Mullerian ducts?
AMH. This is secreted by SERTOLI cells.
How do hormone levels fluctuate throughout development?
RISE in 2nd TRIMESTER, then fall.

Then PERINATAL RISE (up to 2 years), followed by senescence UNTIL PUBERTY.

Women have hormonal oscillations during reproductive years.

Men increase during puberty and maintain through adult life. Testosterone levels drop in the mid-60's.
Why do babies have high PERINATAL hormone surge?
Estrogen and Progesterone-mediated suppression of FSH and LH.
What element of HPA axis is suppressed during childhood?

Kids with gonadal dysgenesis have NORMAL FSH/LH.
NEAR the onset (BUT NOT DURING) of puberty, what is observed in hormone signalling?
GnRH PULSATIVITY returns. INCREASE in FSH and LH pulse amplitude and frequency.

LH pulse begins at night.
DURING puberty, what is observed of LH pulsativity?
Normal LH pulse frequency and amplitude.
What is the FIRST SIGN of puberty in MALES?
Testicular growth.

AT menarche, menstruations are ALWAYS OVULATORY.

Menstrual cycles at first are just endometrial thickenings without eggs
Who has longer half-life? LH/FSH?

LH has very short half-life. hCG is used a long lasting LH mimic.
What are the 2 stages of puberty?
Adrenarche (increase in androgen precursos from adrenal.) This stimulates axillary and pubic hair growth.

ADRENARCHE is the FIRST stage of puberty

Gonadarche (activation of sex steroid secretion. Breast tissue, gonadal growth)
Are adrenarche and gonadarche dependent of one another?
NO! Independent processes. Adrenarche occurs FIRST.
What occurs first, thelarche (breast development) or pubarche?
THELARCHE precedes pubarche by ~6 months. ALTHOUGH RARELY pubarche can occur first.
What stage is MENARCHE in the 4 stages of female pubertal development?
What are the ages for each appropriate step during puberty?
Adrenarche: 6-7
Thelarche (breast buds) by 10
Pubarche by 10.5
Menarche by 12.8
What are the five stages (and ages) for Tanner Breast Staging?
I) Prepubertal
2) Thelarche @ 11
3) Breast tissue surpasses areola @ 12
4) Areola and papilla form second mound @ 13
5) Adult breast @ 15.
What are the 5 stages (and ages) of Tanner Pubic Hair Staging?
1) Prepubertal
2) Curly, pigmented hair laterally @ 11.7
3) Curly spread across pubis @ 12.4
4) Abundant hair limited to pubis @ 13
5) Pubic hair present on medial thigh @ 14.4
INITIAL MENSTRUATION is caused by what hormone?
The growth spurt is determined by onset of puberty? YES! around age 12.
What are ages of male pubertal development?
Adrenarche - Age 8
Testes growth (FIRST SIGN) - Age 10
Pubic hair - 10
Penis growth - 11
Growth - 14.
What are the 5 tanner stages of development in Males for penis/scrotum?
1) Prepubertal
2) Slight enlargement of penis. PRIMARY GROWTH of SCROTUM
3) Increase in both scrotum and penis size
4) Glans increase of penis. Darker, enlarged scortum
5) Adult size for both.
What age does spermatogenesis occur?
Around Tanner stages II and III
Do girls hit growth spurt sooner than guys?
Yes, by 2 years. Guys have faster growth spurt velocity.
What causes acne fulminans?
What causes the suppression of FSH and LH during childhood?
Central INHIBITION of Hypothalamus.
What is leptin's effect on GnRH?
Leptin increases GnRH secretions. OBESITY therefore is an early trigger for puberty.
What hormone is responsible for gonadarche?
What is GABA's role in female puberty?
GABA inhibits GnRH!

Thus GABA agonists can be given to women with precocious puberty to stop her pubertal development.
What is Neuropeptide Y's role in male puberty?
Neuropeptide Y, like GABA, inhibits GnRH in the arcuate nucleus.
What is leptin's role in puberty?
Small levels are required for gonad development.

Alone does not trigger GnRH release.
What is the signal that INITIATES puberty?
UNKNOWN. Suspected that inhibition of GnRH puts "brakes" on puberty.
What are the differences between the mechanisms of puberty between males and females?
PREPUBERTY increases in LH levels at night. Increases in LH pulse frequency and amplitude.
When is the window for IVF implantation?
Between 4 - 10 days POST-OVULATION (~1 week post-ovulation)
What are the MINIMAL ENDOCRINE NEEDS for normal cycling of endometrium?

Estrogen drives the proliferation of endometrium

Progesterone is responsible for changing of tissue types, and prepares endometrium for implantation.
What is endometrial receptivity?

Driven by what hormone?
Period of endometrial maturation which permits the attachment of embryo and establishment of pregnancy

Driven by progesterone.
At what cell stage can the embryo implant?
Embryo must hatch through Zona Pellucida.

The embryo must have passed the morule stage and become a BLASTOCYST.
How long does full implantation take?
1 week total from time of intial implantation to complete coverage.
What cells are responsible for invasion into endometrium?
Trophoblast cells invade in between endometrial epithelial cells.
Where does implanation ideally occur?
Mid-posterior endometrial surface.
What do the trophoblasts do?
They will eventually constitute a large part of the placenta.

They will differentiate into cytotrophoblasts and then syncytiotrophoblasts, which will line the outer membrane of the chorionic villi.

Syncytiotrophoblasts come into contact with material blood.
How does the placenta stay attached to endometrium?
Via trophoblast columns
What are anchoring and floating villi in the placenta?
Anchoring villi give support.

Floating villi give hormonal and nutrient support.

Both these villi come from trophoblasts.
What is the difference between oxygen diffusion from mother to fetus between 1st and 3rd trimesters?
In 1st trimester, the cytotrophoblasts haven't fully differentiated in syncytiotrophoblasts. By 3rd trimester, no cytotrophoblasts remain, so only syncytiotrophoblasts remain as barrier betwene maternal and fetal blood contact.
Where is the main site of hormone production in the placenta?
What is pre-eclampsia?
Hypertension in mother due to loosely attached placenta. Release of fetal products causes systemic reaction in the mother.