Puberty Flashcards
How does the hypothalamus develop into male. In what stage ?
During embryogenesis , testosterone from fetal tested defeminizes by eliminating surge center
Explain how estrodiol plays role in defemenizing male hypothalamus but not in female
Testosterone can cross blood brain barrier and be converted to estrodiol by aromatase. In female, alpha fetoprotein binds estradiol only during fetal stage.
Actuate vs. avpv
Actuate is tonic center. Observed in male and female.
Avpv is surge center. Obs in females.
Major limiting factor of puberty.
What can influence this x3
Insufficient GnRh release at level of hypothalamus due to no stimulus from kiss1. Thereofre, no LH/FSH secretion. Therefore no gamedogeesis , steriodogensis, development of reproductive tissues.
Influences :
Plane if nutrition
Exposure to environmental/ social cues
Genetics
Kiss receptor GPR54 found on GnRH / kiss peptin binding activates…
Gaq increasing IP3/DAG
Explain how GnIH has affect on hormone release.
Gonadotropin inhibiting hormone acts on gnrh center to inhibit release of oh/fsh at level of AP.
Explain how GABA neuron is regulated during puberty
Gananergic neuron will inhibit GABA and therefore increasing LH / FSH release.
How do do steroids affect hypothalamus before and after puberty
Hypothalamus is sensitive to steroids before puberty. When set point changes near puberty, there is no more negative feedback.
Now needs more steroid to cause negative feedback again.
Female will spot before actually being fertile. Explain this. why do secondary features come later?
The first round of LH FSH release are started with follicular development but followed by atresia. When frequencies increase in adult life, oocyte maturation and ovulation will occur.
Secondary features come from the release of estrogen from ovary but cannot happen until oocyte maturation
How does body weight influence puberty in females. Define: Amenorrhea
Moderate obese: Early menstration (boys = opposite)
Primary Amenorrhea= ballet= no period. low wt
Malnurtrition / anarexia = delayed/amenorrhea
What evidence suggest that puberty/ cycles are nrg related ?
When glucose oxidation is inhibited, estrous cycles are distrucpted due to GnRH secretions.
Show that GnRH are sensistive to [glu]
What effect does leptin have on onset of puberty? Where is leptin secreted from? Where are its receptors?
[plane of nurtrition]
Leptin is secreted from adipose tissue and thought to have receptors in hypothalamic neurons that influence GnRH secretions.
Leptin may notify these neurons when a specific fat threshold has been achieved.
Do genetics affect puberty
YES!
Environment/ Seasonal
Born in spring and have adequate nutrition to eat and grow and reach puberty. in fall, they can become fertilized and pregnanat but will not give birth until spring.
but if u change light pattern in sheep. you can manipulate and put them in estrous.
GnIH may have receptors specific for melatonin to be specific to environmental puberty onset
Social conditions that influence/ inhibit puberty
Pharomonal substances present in urine. with female gilts , they experience pubeerty when in presence of male.
Can inhibit :
small groups of all females. so dont house gilts together !!
