Exam 3 Lecture Notes Flashcards
estrus
Recurring period of sexual receptivity and fertility in many female mammals. During estrus, the female is in heat, indicating that she is ready to mate and can conceive.
what is estrus greek for?
frenzy
estrous
a period of sexual receptivity is determined by the interval from one estrus to the next
estrous cycle length: cow
21 days
estrous cycle length: ewe
16 days
estrous cycle length: sow
21 days
estrous cycle length: mare
21 days
when should you breed most animals?
when they are in heat
follicular phase
follicle growth, Graafian follicle forms
what happens to the follicle during estrus?
ovulation occurs
luteal phase
the corpus luteum is present
understand how blood flow is affected by the estrous cycle
blood flow goes down during estrus and then will increase during the luteal phase
understand how hormones are changed during the estrous cycle
estrogen increases before estrus, LH surge during estrus so ovulation can occur, FSH increases at the same time as LH, progesterone decreases during estrus and then increases after esturs (when the CL is formed), PGF2a increases before estrus to regress the CL
Hormonal Control of the Estrus Cycle
(diagram)
1. hypothalamus releases GnRH to the anterior pituitary
2. FSH and LH is released from the anterior pituitary and goes to the follicle
3. estrogen is produced by the follicle and goes to the hypothalamus, uterus, and anterior pituitary
4. the anterior pituitary released LH which goes to the follicle (ovulation occurs) and corpus luteum (form the CL)
5. CL produces progesterone which goes to the uterus, hypothalamus, and uterus
6. the uterus releases prostaglandin which will regress the CL
menses
menstruation (endometrial sloughing)
follicular phase of the menstrual cycle
menses (5 days) plus the proliferative phase (5 days)
luteal phase during the menstrual cycle
secretory phase (14 days), CL present
________ us needed for cycling, without it no cycling would occur (how seasonal animal stop cycling out of season)
GnRH
the estrous cycle: estrogen
high during heat, the animal will show signs of estus
___________ has a positive feedback mechanism to make LH surge
estrogen
the estrous cycle: LH
ovulation hormes, a surge of LH causes ovulation to occur
the estrous cycle: CL
produces progesterone, forms where the oocyte ovulates from
what happens to the CL if pregnancy occurs? What happens to the CL if there is no pregnancy?
if pregnant the CL will be maintained, if not pregnant PGF2a is released and luteolysis occurs which will degrade the CL
___________ declines which allows estrogen to increase for signs of heat and ______ will surge and ovulation can occur
progesterone, LH
luteal phase
CL present
follicular phase
follicle is dominant, present
the menstrual cycle: menses
shedding of the endometrial lining (about 5 days)
the menstrual cycle: proliferative phase
the endometrial lining will begin to grow back
why does there have to be an endometrial lining created before ovulation?
the lining must be present for the embryo to implant, without it the embryo cannot implant
the menstrual cycle: secretory phase
hormones are being released after ovulation, progesterone is high
what happens to progesterone if pregnancy occurs? what happens is pregnancy does not occur?
high progesterone (present CL) is ready for pregnancy and no pregnancy means that there is no CL which means there is no progesterone which causes menses
the menstrual cycle: follicular phase
follicle growth (1/2 of the cycle)
the menstrual cycle: luteal phase
CL is present (1/2 of the cycle)
spiral arteries
arteries within the endometrial lining, ensured that after sloughing the woman does not bleed out
estrous vs menstral cycle: follicular phase
- estrous: short (20% of the cycle)
- menstrual: long (50% of the cycle)
estrous vs menstral cycle: ovulation
- estrous: beginning and end (day 0 and 21)
- menstrual: middle (day 14)
estrous vs menstral cycle: luteal phase
- estrous: 80% of the cycle
- menstrual: 50% of the cycle
estrous vs menstral cycle: fertile phase
- estrous: 24 hours or less
- menstrual: up to 6 days before ovulation
estrous vs menstral cycle: endometrial sloughing
- estrous: NONE
- menstrual: after luteolysis
estrous vs menstral cycle: luteolysis
what hormone causes it? and where does it come from?
- estrous: uterine PGF2a
- menstrual: ovarian PGF2a
estrous vs menstral cycle: sexual receptivity
- estrous: well defined
- menstrual: relatively uniform
estrous vs menstral cycle: progesterone function and sexual receptivity
- estrous: inhibits GnRH release inhibiting sexual activity
- menstrual: inhibits GnRH but does not influence sexual receptivity
estrous vs menstral cycle: menopause
- estrous: NONE
- menstrual: well characterized
estrous cycle vs the menstrual cycle
- the follicular phase is short in estrous and long in menstrual
- the ovulation occurs at the beginning and end of estrous and in the middle of menstrual cycle
- the luteal phase is 80% of the cycle in estrous and 50% of the menstrual cycle
- the fertile period of the estrous cycle is 24 hours or less and the menstrual cycle. is up to 6 days before ovulation
- endometrial sloughing does not occur in the estrous cycle but occurs after luteolysis in the menstrual cycle
- luteolysis occurs due to uterine PGF2a in estrous and from ovarian PGF2a in the menstrual cycle
- sexual receptivity is well defined in estrous and relatively uniform in menstrual cycle
- progesterone function and sexual receptivity inhibits GnRH release inhibiting sexual activity in estrous and in the menstrual cycle progesterone inhibits GnRH but does not influence sexual receptivity
- menopause does not occur in estrous and is well characterized in menstrual cycle
corpus luteum formation
- hypertrophy of granulosa and theca cells
- folding of follicular wall
- breakdown of the basement membrane
- pushing of cells towards the center
- angiogenesis
- lutenization
angiogenesis
formation of new blood vessels (in the CL)
4 steps of angiogenesis
- basement membrane breakdown
- production of angiogenic factors by granulosa cells
- mitosis and migration of endothelial cells
- capillary tube formation
CL classification (3 types)
- corpus hemorrhagicum
- corpus luteum
- corpus albicans
corpus hemorrhagicum
- blood, red color
- occurs after rupture
corpus luteum
- mature CL
- yellow color
- lutenization occurs
corpus albicans
- white color
- before degradation
when no pregnancy occurs __________ will regress the CL
PGF2a
CL Functions
- produce progesterone (and oxytocin)
- requirement for the maintenance of pregnancy
- stimulates mammary development
- controls the ovarian cycle (inhibit ovulation and estrus)
