LIFECYLE EXAM 3

follicular and luteal

Phases of ovarian cycle

Follicular phase

Follicles grow, estrogen rises, and the cycle builds up to ovulation

Luteal phase

AFTER OVULATION Progesterone dominates, preparing the uterus and stabilizing the lining

estrogen

What does the follicle produce?

Follicle

small sac in ovary that contains immature egg/oocyte

estrogen/ estradial

Which hormone rises as follicle grows?

Corpus luteum

leftover follicle after ovulation that produces progesterone

Progesterone

thickens and maintains the endometrium for potential implantation

Progesterone

What does CORPUS LUTEUM produce if ovum is FERTILIZED?

Corpus luteum breaks down, progesterone drops, menstruation occurs

What happens if fertilization doesn’t occur?

hCG

What hormone stops the corpus luteum from breaking down?

Placenta

What makes most of the hormones for pregnancy?

Corpus luteum (progesterone)

What makes the hormones for pregnancy while the placenta grows (ie. first 10-12 weeks)?

KNDy neuron stimulates hypothalamus to secrete GnRH, pituitary releases LH and FSH, ovary produces estradiol and progesterone

steps of the HPG axis of the female

Estrogen (estradiol)

What hormone is rising in the women’s blood due to the growth of the follicle?

High estrogen levels

stimulates positive feedback on hypothalamus to release more GnRH

High estrogen levels

causes increased GnRH that leads to release of huge SURGE of LH from pituitary

LH surge from pituitary

What triggers OVULATION?

proliferative and secretory

Phases of endometrium

Proliferative phase

occurs after MENTSTRATION and lasts until ovulation, endometrium builds back up

Secretory phase

occurs after OVULATION, lining becomes thick and stable to prepare or implantation

Estrogen (from follicle)

drives PROLIFERATIVE phase of ovarian cycle

Progesterone (from corpus luteum)

drives SECRETORY phase of endometrial cycle

Ovulation

When does POSITIVE feedback occur during the ovarian cycle?

Follicular and luteal phases

When does NEGATIVE feedback occur during the ovarian cycle?

HPG axis

key hormonal system that regulates reproduction and sexual development in both males and females

GnRH

signals the pituitary to synthesize and secrete gonadotropins LH and FSH

hypothalamus

Releases Gonadotropin-Releasing Hormone (GnRH) in a pulsatile fashion

Pituitary

Releases Luteinizing Hormone (LH) and Follicle-Stimulating Hormone (FSH) in response to GnRH

Ovaries

Produces estrogen and progesterone, regulate the menstrual cycle, and support ovulation

Testes

Produces testosterone, which supports sperm production and secondary sexual characteristics

LH/FSH

During OVULATION estrogen stumulates ____ release from pituitary

Hypothalamus pituitary portal system

allows the hypothalamus to control the anterior pituitary efficiently by sending hormones without being diluted in the general circulation

Kallmann syndrome/congenital hypogonadotropic hypogonadism

genetic disorder that affects the development of the HPG axis, leading to delayed or absent puberty (hypogonadism)  and impaired sense of smell (anosmia or hyposmia)

Pulses

manner of GnRH secretion

pulses

_____ of GnRh are required to sustain LH and FSH secretion

Down-regulates GnRH receptors, stops gonadotropin secretion 

What happens if there is continuous (not pulsatile) GnRH stimulation to the pituitary cells?

GnRH agonist

What is used to STOP LH and FSH secretion?

Glycoprotein hormone

hormones that contain two subunits: common alpha and distinct beta

TSH, LH, FSH, hCG

Hormones that are GLYCOPROTEINS

All have same alpha subunit

Why are glycoprotein hormones (ex: TSH and hCG) sometimes able to stimulate targets of other glycoprotein hormones?

LH and FSH

Gonadotropin hormones released from the pituitary

Leydig (male) and thecal (female) cells

Targets of LH

sertoli (male) and granulosa (female) cells

Targets of FSH

fetal testes (male) and corpus luteum (female)

Targets of hCG

KNDY neuron

primary target of sex steroids mediate negative feedback, SOURCE of GnRH pulses

Leydig cell

stimulated by LH to make TESTOSTERONE 

Sertoli cell

stimulated by FSH to help SPERM MATURE

FSH

starts folliculogenesis (eggs begin to mature)

LH

triggers OVULATION (egg release) and PROGESTERONE production

KNDy neurons

control the release of GnRH in a pulsatile (rhythmic) manner, which is essential for proper function of the HPG axis

Kisspeptin

neuropeptide made by KNDy neurons that directly stimulates GnRH neurons

peptide

what type of hormones are LH, FSH, and hCG

G-protein couple receptor (GPCR)

signaling pathways of PEPTIDE hormones (FSH, LH, hCG)

LH and FSH

released by ANTERIOR PITUITARY and stimulate release of estrogens, progestogens, and testosterones from gonads

estrogens, progesterones, testosterones/androgens

sex steroids

DHEA

precursor for sex hormones, made mostly by adrenal glands, stimulated by CRH and ACTH 

steroid (estrogen, testosterone, progesterone) 

hormones that bind INTRACELLULAR RECEPTORS to modify gene transcription

peptide 

which hormones are FASTER at signaling peptide or steroid 

cholesterol

what are all STEROIDS derived from?

SHBG (sex hormone binding globulin)

what carrier protein transports ESTROGEN and TESTOSTERONE in the blood

CBG (corticoid binding globulin)

what carrier protein transports PROGESTERONE and CORTICOSTEROIDS in the blood

more bound estrogen (relative to testosterone) 

what does INCREASED SHBG indicate about hormone levels in the blood 

more bound testosterone (relative to estrogen)

what does DECREASED SHBG indicate about hormone levels in the blood 

free form

in general, what is the ACTIVE form of sex hormones, i.e which form is more accurate to measure levels?

classical/genomic pathway

steroid hormone changes cell function by changing which genes are turned on or off

nonclassical/nongenomic pathway

steroid hormone causes rapid cellular changes without altering DNA transcription

nonclassical/nongenomic

which pathway of steroid action is FASTER?

nonclassical/nongenomic

which pathway of steroid action does NOT involve nuclear receptor binding to genomic DNA

classcial/genomic

which pathwaway of steroid action is the PREDOMINANT pathway

corticosteroids (ex: prednisone, dexamethasone ect) 

can cause long-term and down stream implication under chronic use as they ALTER GENE TRANSCRIPTION

progestogens (ex:progesterone and hydrxyprogesterone)

support pregnancy and involved in mammary gland development

progestins (synthetic, ex: MPA) 

used as contraceptive, hormone therapy, prevention of preterm birth, and in gynecological disorders

milfepristone 

ANTI-PROGESTOGEN that has clinical uses as emergency contraception, medical abortion, treating heavy menstral bleeding

ulipristal acetate

ANTIPOGESTOGEN that has clinical uses as emergency contraception and UTERINE FIBROID REDUCTION

estrone (E1)

less potent form of estrogen predominant AFTER MENOPAUSE

estradiol (E2)

MOST POTENT form of ESTOGEN predominant during CHILD BEARING YEARS

estriol (E3)

LEAST potent form of ESTROGEN predominant during PREGNANCY

tamoxifen

estrogen antagonist in breast used to treat breast cnacer AND estrogen agonist in uterus that can cause uterine cancer  

estrogen

stimulates breast and endometrial tissue and supports bone health

endometrial cancer (if unapposed by progestogen), hyper coagulabiltiy, VTE

adverse reactions of supplemental ESTROGEN

androgens (testosterone) 

promotes growth and developement of sex organs and maintains MALE secondary sex characteristics, increases muscle mass and bone density 

androgens

used to treat HYPOgonadism

androgen receptor antagonist

treatment for prostate cancer and hyperandrogenism that can cause sexual dysfunction and bone frarctures

5a-reductase inhibitor 

used to treat benign prostate hypertrophy, male pattern hair loss, and excess hirasuitism by blocking enzyme that converts testosterone to DHT

14 days

on average how long is each phase of the OVARIAN cycle?

thecal cells (of follicle)

stimulated by LH to make testosterone

granulosa cells (of follicle)

stimulated by FSH to turn testosterone into estrogen 

increased LH which increases estrogen levels

at high estrogen levels what happens as a result of the POSITIVE feedback loop?

progesterone

what do thecal and granulosa cells produces AFTER ovulation in the LUTEAL PHASE?

hCG

hormone produced by zygote that stimulates corpus luteum to produce progesterone to support pregnancy

proliferative phase

first 14 days of endometrial cycle where ENDOMETRIUM is FAST GROWING 

secretory phase

second 14 days of endometrial cycle where endometrial growth STABILIZES and secretes GYCOGEN RICH FLUID to support potential zygote

menses 

shedding of endometrial lining as a result of no zygote implanting 

secretory phase

when does the IMPLANTATION WINDOW occur in the ENDOMETRIAL CYCLE?

activation of KNDy neurons by high estrogen levels 

what causes the LH SURGE that drive ovulation?

12-52 years old

normal AGE range for menses

10-80 ml/28 days

normal QUANTITY of blood from menses

2-8 days

normal DURATION of menses

every 26-35 days

norrmal FREQUENCY of menses