Ch. 5: Sex Hormones, Sexual Differentiation and the Menstrual Cycle Flashcards
what is the typical prenatal sexual differentiation?
male: XY
female: XX
what are the gonads and hormones associates with female and male?
male: testes, testosterone
female: ovaries, estrogen & progesterone
for male and females, what is the genital and brain differentiation that occurs?
males:
genital- wolffian ducts (penis, scrotum)
brain- hypothalamus
females:
genital- mullerian ducts (clitoris, labia)
brain- hypothalamus
what do wolffian ducts turn into?
turns into the epididymis, the vas, and the testes
what does the mullerian ducts turn into?
turns into the upper part of the vagina, fallopian tubes, uterus, fimbriae
SRY
sex-determining region, Y chromosome
leads to the development of testes
TDF
testis-determining factor which can differentiate gonad into testes
write out how a y chromosome leads to the secretion of AMH
y chromosome–> synthesis of TDF–> differentiate gonad–> testes–> testes secrete Anti-Mullerian Hormone (AMH)
AMH
Anti-Mullerian Hormone, also called Mullerian Inhibiting Substance (MIS)
the glans penis is homologous to…
the glans clitoris
the scrotum is homologous to…
the outer lips
the testes are homologous to…
the ovaries
when do the testes decend?
7 months post-conception
where are the testes located before they descend?
in the inguinal canal
why can’t sperm stay up inside the body?
because they cannot remain viable at the body temp of 98.6 (too warm)
cryptorchidism
undescended testes
inguinal hernia
intestines gets into the inguinal canal and is painful but treatable after surgery
CAH (Congenital Adrenal Hyperplasia)
- genetic female, XX
- hyperactive adrenal gland: oversecretes androgens prenatally which leads to ambiguous genitals (ex: large clit and lips)
AIS (Androgen Insensitivity Syndrome)
- genetic male: XY
- cells are insensitive to androgens which leads to ambiguous genitals
What did John Money’s Research and Treatment (1960s-1990s) contribute to the study of atypical prenatal sexual differentiation?
- worked cases in which children were assigned a gender before 18 months of age through surgery to make their ambiguous genitals more typical
- collected data on how well it worked
- later, found negative cases
what is the intersex society of north america (ISNA) called now?
Accord Alliance
what was being intersex called in the past?
“Disorder of Sex Development”
not a diagnosis in DSM-5 (Diagnostic & Statistical Manual-5th Edition)
what is the current approach towards intersex individuals?
- tested to determine the cause of ambiguous genitals
- concerns are rooted in gender binary
- research informs what approach is best for the child
ex: CAH, XX children do well raised as girls and can be fertile
Endocrine disrupters
chemicals found in the environment that affect the endocrine system and biological functioning of animals, including humans
how does atrazine disrupt endocrine production?
Atrazine inhibits binding to estrogen receptors
how does PCBs disrupt endocrine production?
PCBs (banned, but were in plastic, paint) are anti-estrogens and anti-androgens
prenatal period
time from conception to birth
androgens
group of sex hormones- one of which is testosterone
pituitary gland
small endocrine gland located on the lower side of the brain below the hypothalamus
regulates levels of sex hormones
what is the feedback loop that regulates female sex hormone production?
hypothalamus-pituitary-gonad feedback loop (HPG axis)
it is a neg. feedback loop
what does each component of the HPG axis produce?
Hypothalamus: GnRH (Gonadotropin Releasing Hormone)
Pituitary: FSH (follicle stimulating hormone), LH (luteinizing hormone), Prolactin (stimulates milk production, & Oxytocin (milk ejection & affectionate bonding)
Gonads: estrogen, progesterone, testosterone & inhibin (provides neg feedback to FSH production)
Draw out the HPG axis for males
H–(GnRH)–> pituitary–(A: FSH or B: LH)–> A: spermatogenesis or B: testosterone secretion
testosterone secretion provides feedback to spermatogenesis and hypothalamus (which also provides feedback on spermatogenesis)
testes–(inhibin)–> pituitary
Draw out HPG axis for females
H–(GnRH)–> pituitary–(A: FSH or B: LH)–> A: follicle & ovum development or B: estrogen secretion–> H & P –> ovaries–> follicle & ovum development–(estrogen & progesterone)–> endometrium
FSH & LH provide feedback to each other
What are the phases of the menstrual cycle?
1- follicular
2-ovulation
3-luteal
4-(menstruation)
What are the phases of menstruation in the uterus?
- proliferative (follicular)
- ovulation
- secretory (luteal)
- menstruation
what affects the length of a cycle and timing of ovulation?
- BBT (basal body temp)
- length of luteal phase
dysmenorrhea
painful menses because of prostaglandins
amenorrhea
absence of menstruation
what causes amenorrhea?
- low percent body fat
- running marathons
- anorexia
endometriosis
growth of endometrium in places other than inside uterus- like fallopian tubes
Klinefelter’s syndrome
XXY
affect testicular growth, resulting in smaller than normal testicles, which can lead to lower production of testosterone
Guevedoces
term used in the DR for intersex children
undifferentiated state
stem cells are blank-slate cells that remain in an undifferentiated state, that is they have not yet started changing into specific cells, such as nerve or blood cells
GnRH
gonadotropin-releasing hormone
at how many weeks after conception does differentiation start?
7 weeks after conception
at how many weeks post-conception can you determine the sex of the fetus?
12 weeks
at how many weeks post-conception do the testes begin to descend?
10 weeks
how long after conception do the testes travel down into the scrotum?
7 months after conception
menarche
first menstruation
leptin
a hormone-related to the onset of puberty
kisspeptin
a hormone involved in the initiation of pubertal development
adrenarche
time of increasing secretion of adrenal androgens
