Lecture 27 3/22/24 Flashcards
What is the estrous cycle?
interval between two ovulations
What are the phases of the estrous cycle, based on dominant structure?
-follicular phase
-luteal phase
What are the primary behavioral events during estrus?
-sexual receptivity
-copulation
What are the characteristics of the follicular phase?
-period from regression of CL to ovulation
-relatively short
-primary structures are growing dominant follicles
-follicles produce estradiol
What are the characteristics of the luteal phase?
-period from ovulation until CL regression
-longer phase
-dominant structure is corpora lutea
-CL produces progesterone
What are the stages of the estrous cycle?
-proestrus
-estrus
-metestrus
-diestrus
Which stages occur during the follicular phase?
-proestrus
-estrus
Which stages occur during the luteal phase?
-metestrus
-diestrus
What are the characteristics of proestrus?
-begins when progesterone declines
-terminates at onset of estrus
-follicle development and rise in estradiol
What are the characteristics of estrus?
-most recognizable stage
-peak of estradiol
-sexual receptivity and mating
-ovulation occurs
What is standing estrus?
the female’s willingness to accept a male for mating
What are the characteristics of metestrus?
-between ovulation and formation of functional corpora lutea
-initial development of CL
-transition from estradiol to progesterone
What are the characteristics of diestrus?
-mature phase of CL
-progesterone dominance
-period of maximum luteal function
-longest stage of estrous cycle
-ends when CL is destroyed
How does the estrous cycle compare to the menstrual cycle?
Estrous:
-interval between ovulations
-short follicular phase
-ovulation to begin cycle
Menstrual:
-interval between menses
-long follicular phase
-ovulation mid-cycle
What occurs during the proliferative and secretory phases of the menstrual cycle?
changes in endometrial thickness
What are the major events that occur during the follicular phase?
-elevated gonadotropins
-follicular growth
-preparation for ovulation
-sexual receptivity
-ovulation
What are the characteristics of ovulation?
-after luteolysis and absence of progesterone
-dominant follicle secretes large amount of estrogens
-feedback to surge center leads to LH peak
What happens after the surge center causes LH to peak?
-increase in PGE2 and blood flow
-increase in PGF2a
-increase in intrafollicular pressure
-disruption of connective tissue of follicle/weakening of follicle wall
-change from estradiol to progesterone
-removal of meiotic inhibition
-1st meiotic division