Physiology E2: Puberty, Estrous
Cycles, Repro Behavior (Smith)
_________ is the acquisition of reproductive competence - ANS Puberty
Puberty occurs when there is secretion of __________ in appropriate frequency and quantity - ANS
GnRH
Do males and females have a tonic center? A surge center? - ANS Both have a tonic center, only
females have a surge center
What defeminizes the hypothalamus in fetal males? - ANS Testosterone from fetal testis converts to
estrogen, crosses the BBB, and eliminates the surge center
In fetal females, _______________ binds estrogen and prevents crossing of blood-brain barrier so
the surge center remains - ANS Alfa-fetoprotein
In what fetal sex does Alfa-fetoprotein bind to estrogen? - ANS Females (lets the surge center
develop)
What are 3 clinical definitions of puberty in females? - ANS Age at first heat/estrus
Age at first ovulation
Age when pregnancy can be maintained without deleterious effects
Females can usually maintain a pregnancy without deleterious effects at ___% of adult body weight -
ANS 65%
What are clinical definitions of puberty in males (from youngest to oldest)? - ANS Expression of
behavioral traits
First ejaculation
Sperm appear in ejaculate
Sperm appear in urine
Ejaculate contains a threshold number of sperm (to achieve pregnancy)
What 4 factors affect when puberty occurs? - ANS Nutrition/fatness
Threshold body size/composition
Exposure to environmental and social cues
Genetics (breed, scrotal circumference of father)
What are 4 environmental and social cues that can influence when puberty occurs? - ANS Season of
birth
photoperiod in seasonal breeders
Presence of opposite sex
, Density of same sex groups
What animals have season of birth and photoperiod affect age at puberty? - ANS Seasonal breeders
(sheep, goats, cats)
Does larger groups of animal reach puberty faster or slower? - ANS Faster
Do fall or spring born sheep/goats reach puberty faster? - ANS Spring
Does the presence of an intact male increase or decrease time to puberty? - ANS Decrease (even if
no physical contact)
What is the major limit on puberty onset? - ANS Failure of hypothalamus to produce suff. quantities
of GnRH to cause gonadotropin release
True or false: Puberty does not start earlier because the anterior pituitary cannot yet produce FSH
and LH - ANS False
True or false: Puberty does not start earlier because the gonads do not yet respond to LH and FSH -
ANS False
True or false: Puberty does not start earlier because the hypothalamus does not produce enough
GnRH - ANS True
In a prepubertal female, the ________ center in hypothalamus releases small quantities of GnRH at
low frequency which is not sufficient to stimulate the pituitary - ANS tonic
How do females transition into puberty? - ANS Negative feedback on the tonic center is slowly lost;
higher and higher levels of GnRH lead to higher estrogen (E2) which eventually stimulates the surge
center
In a female approaching puberty, eventually ____________ is high enough to cause the surge center
to discharge large quantities of GnRH resulting in ovulation and puberty ensues - ANS estrogen
True or false: After a female's E2 is high enough to stimulate the surge center and discharges
adequate GnRH, normal cycling pattern arises - ANS True
In females, the ____ center is responsible for preovulatory surge - ANS surge
In males, small amount of _____/_____ have negative feedback on thehypothalamus - ANS
testosterone/estradiol
As males transition into puberty, GnRH neurons become ______ sensitive to T and E2 - ANS less
How do males transition into puberty? - ANS GnRH neurons become less sensitive to T and E2
negative feedback. The hypothalamus eventually produces enough GnRH to produce adequate
FSH/LH
What is the average age of puberty in cattle? - ANS 11 months
What is the average age of puberty in horses? - ANS 14 months
What is the average age of puberty in sheep, goats and pigs? - ANS 7 months
What is the average age of puberty in dogs and cats? - ANS 9 months (down to 4 months in cats and
up to 24 months in large dogs)
Les avantages d'acheter des résumés chez Stuvia:
Qualité garantie par les avis des clients
Les clients de Stuvia ont évalués plus de 700 000 résumés. C'est comme ça que vous savez que vous achetez les meilleurs documents.
L’achat facile et rapide
Vous pouvez payer rapidement avec iDeal, carte de crédit ou Stuvia-crédit pour les résumés. Il n'y a pas d'adhésion nécessaire.
Focus sur l’essentiel
Vos camarades écrivent eux-mêmes les notes d’étude, c’est pourquoi les documents sont toujours fiables et à jour. Cela garantit que vous arrivez rapidement au coeur du matériel.
Foire aux questions
Qu'est-ce que j'obtiens en achetant ce document ?
Vous obtenez un PDF, disponible immédiatement après votre achat. Le document acheté est accessible à tout moment, n'importe où et indéfiniment via votre profil.
Garantie de remboursement : comment ça marche ?
Notre garantie de satisfaction garantit que vous trouverez toujours un document d'étude qui vous convient. Vous remplissez un formulaire et notre équipe du service client s'occupe du reste.
Auprès de qui est-ce que j'achète ce résumé ?
Stuvia est une place de marché. Alors, vous n'achetez donc pas ce document chez nous, mais auprès du vendeur lectjoseph. Stuvia facilite les paiements au vendeur.
Est-ce que j'aurai un abonnement?
Non, vous n'achetez ce résumé que pour €10,83. Vous n'êtes lié à rien après votre achat.