Cycles Flashcards
What are the two main phases?
follicular, luteal
What 2 phases can follicular be split into?
proestrus, estrus
What 2 phases can luteal be split into?
metestrus, diestrus
What is the difference between estrus and estrous?
estrus describes sexual receptivity (“heat”), estrous describes the cycle
What happens during proestrus? How long is it?
Drop in progesterone due to luteolysis, increase in FSH and LH and estradiol due to follicular maturation
2-5 days
What happens during estrus?
peak estradiol follicles due to dominant follicle
peak FSH, LH
ovulation
What happens during metestrus?
follows ovulation
ovulated follicle undergoing luteinization to CL
LH, FSH, estradiol, progesterone low (P increase at end)
What happens during diestrus?
high circulating progesterone is dominant
LH, FSH, estradiol low
important to support uterine endometrium for pregnancy
terminated with luteolysis
What are follicular waves?
multiple waves of follicular development that never reach completion because of inadequate hormone signals
What are the 3 phases of follicular development?
recruitment, selection, dominance
What happens during the recruitment stage of folliculogeneis?
entrance of cohort of antral follicles into gonadotropin-dependent stage
What happens during the selection stage of folliculogenesis?
reduction in number of recruited follicles to 1 follicle (or number of follicles that normally ovulate in that species)
What happens during the dominance stage of folliculogenesis?
inhibition of further recruitment and development of other follicles, this one grows to be ovulated or becomes atretic due to wrong stage
What is atresia?
follicle degeneration
What is spontaneous ovulation?
ovulate regularly after end of each follicular cycle
induced by ovarian steroids and gonadotropins
humans, sheep, cattle
