320 Exam 2 seasonal cyclicity and menstrual cycle

What is the purpose of seasonal anestrus-cyclicity

Prevents females from conceiving when the survival of the embryo/neonate would be low

In females, ovarian cycles are confined to less stressful times of the year

In males, testicular size and testosterone production adn spermatogenesis rises in the fall in synchrony with female cyclicity

What are seasonal breeders?

they give birth during spring when nutrtion is sufficient for lactation adn growth of the neonate

What are the types of seasonal breeders?

Obligatory and Facultative (opportunistic)

What is an obligatory breeder?

rely on seasonal cues to predict when conditions are favorable to reproduction and rearing young.

What is a facultative (opportunistic) breeder?

react directly to changes in an enviromental variable-not linked to seasonal cues (day length)

What happens during anestrus in obligatory seasonal breeders?

GnRh pulse frequency and LH secretion are low, follicles may grow but fail to obtain preovulatory status

The end of anestrus is regulated by what in obligatory seasonal breeders.

The duration of photoperiod length regulating the duration of melatonin release, ultimately affecting GnRH pulse frequency and gonadotropin secretion. Day length is detected by the retina, and info is sent to the SCN via the optic nerve. Info is then sent to SCG, where sympathetic neurons project into the pineal gland to regulate melatonin release.

What is melatonin?

"hormone of darkness" secreted by the pineal gland in a circadian fashion, higher production in darkness and provides accurate information about the light/dark cycle. does not directly affect GnRH secretion but regulates other brain peptides, proteins, adn neural circuitry impacting GnRH.

What is menarche?

first menstrual period

What is amenorrhea?

lack of bleeding

what is dysmenorrhea?

painful menstruation

What is menorrhagia?

excessive menstrual bleeding

What is oligomenorrhea?

little bleeding

What is the average menstrual cycle length?

28 days, varies more in teenagers and less in women of reproductive years

What are some key differences between the menstrual and estrous cycle

no endometrial sloughing in the estrous cycle

no clearly defined period of sexual receptivity

What are the four phases of the menstrual cycle?

menses, follicular phase, ovulation, luteal phase

What does luteolysis in the primate involve?

-does not require a uterus

-in the absence of pregnancy, the Cl self-destructs

CL life span is 12-14 days unless pregnant

menstruation

What causes the variation in menstrual cycles?

teh length of the follicular phase

Does teh lactational amenorrhea method of family planning work?

Only if the criteria are strictly followed, success is dependent on a number of things.