Test 1: lecture 2 repro phys Flashcards
The — ligament carries blood and lymphatic vessels and nerves to the ovaries, oviducts, uterus and cervix.
broad
oocytes are released from the — on mare ovary
ovulation fossa
true or false
horse ovary will form ovulation papilla after ovulation
false
* oocycte released through the ovulation fossa in a horse
three parts of the oviduct
Infundibulum – funnel-shaped end nearest the ovary; covers the ovulation fossa during ovulation.
Ampulla - site of fertilization.
Isthmus - narrow portion nearest the uterus; enters the uterus by a small
projection into the uterine lumen, oviduct papilla.
— is the site of fertilization
ampulla
how does fertilized egg get from oviduct to uterus in a horse
makes PGE and sphincter lets it through
if you can feel endometrial folds the mare is —
not pregnant
mare uterus what is this a picture of
uterine horn during estrus- endometrial folds are swollen and appear hypoechoic(darker)
edematous endometrial folds will look — on ultrasound
hypoechoic (darker)
what estrous phase?
estrus- sexually receptive
- large endometrial folds are hyoechoic (darker)
what is uterine milk in horse
made by endometrial glands, feeds embroy prior to placenta becoming functional
- 60 days in mare
beginning of cervix is called
portio vaginalis
progesterone causes the cervix to
close
Pregnant- long tightly closed, dull yellow gray portio vaginalis positioned in the center of the cranial vaginal
↑progesterone
anestrus- closed but not tightly closed, dull yellow gray cervix neutrally positioned in the anterior vagina
closed, diestrus- shapely closed pink, wet as a mare in diestrus
↑progesterone
estrus, relaxed-flat relaxed with little shape, red, glistening, inviting as a mare in estrus.
↑estrogen
Follicles produce
estrogen and inhibin
corpus luterum produces
progesterone
horses have what type of estrous cycle
seasonally polyestrous
* 21 days
The retina of the eye is stimulated by light which elevates the tonic excitation of retinal neurons and transmits this excitation to the — of the hypothalamus.
suprachiasmatic nucleus
the suprachiasmatic nucleus is connected by a second nerve tract to the —
superior cervical ganglion.
Stimulation of the superior cervical ganglion causes an — at the superior cervical ganglion.
inhibitory response
longer days will result in low — secretion and then low — release (during periods of light) being released from the pineal gland.
norepinephrine
melatonin
caused by inhibition by the superior cervical ganglion
Low melatonin results in the excitation of RFRP neurons which cause — in RFRP-3.
an increase
↑RFRP-3 in mares will cause
IN the mare RFRP-3 stimulates the kisspeptin neurons to produce kisspeptin-10 which acts directly on GnRH neurons to increase GnRH → stimulates the secretion of FSH and LH. The ovaries are then stimulated to have follicular waves and ovulate.
In the ewe elevated RFRP results in — concentration of kisspeptin-10 and — GnRH.
low
low
normal length of the estrus cycle of a mare
21-22 days with leutiolisis at day 14
mares during the summer will have a longer or shorter estrus phase
shorter, longer days= less days “in heat”
spring= 7 days
summer 2 days
fall 7 days
Ovulation occurs — hours before the end of estrus.
0 to 48
In the mare, signs of estrus are due to
the absence of progesterone and not just to the presence of estradiol. “Silent heat” mares may cycle regularly but not be detected to be in estrus.
what are the hormone levels during estrus
Plasma estradiol concentrations are elevated.
Plasma FSH concentrations are increasing (inhibin, thought to be produced by the dominant follicle, has a negative feedback on FSH).
LH peaks.
Plasma progesterone concentrations are low (< 1 ng/ml).
during estrus the cervix and uterus are
cervix: relaxed, open and edematous (contrast with anestrous cervix that may be open but is thin-walled).
The uterus is edematous but not turgid, as in the cow. Edema of endometrial folds may ultrasonographically appear as spokes in a wheel.
ovulatory follicles in a mare are how big
35-50 mm in diameter
measures 37mm
follicle in ovary
- mare in estrus/heat with dominant follicle
— occurs 0 to 48 hours before the end of estrus
Ovulation
This means that some mares will go out of heat the day they ovulate but some mares will ovulate and not go out of heat for another 2 days.
— is the behavior demonstrated when a mare is rejecting the advances of a stallion. Not in heat!
diestrus
the — becomes a CL which matures 6 to 7 days after ovulation
Corpus hemorrhagicum
In the nonpregnant mare, luteolysis occurs — days after ovulation.
14
ovary
Sonogram of the right ovary of a mare depicting four anechoic (black) follicles and a hyperechoic corpus luteum.
- ovulated in the last 14 days, ↑ progesterone
if horse not pregnant — is released by the — at day 14 and will cause
PGF2⍺
uterus
luteolysis of corpus luteum → will die and horse will come back into heat
what does it mean when horse has mid-cycle follicular wave
has two cycles of follicle formation but only one will lead to ovulation
what happens to ovaries, cervix and uterus during anestrus
- The ovaries are inactive.
- The uterus is flaccid.
- The cervix may be moderately closed or thin and open. (no hormones to keep it closed)
- Ovarian steroid hormone concentrations are low.
when is the vernal transitional breeding season
spring
when is the autumnal transitional breeding season
fall
during transitional breeding season what happens to ovaries and cervix
The ovaries have numerous follicles. The cervix does not tightly close until an ovulation occurs. Mares will display long periods of estrus.
- autumnal- will form large follicles but LH too low to cause ovulation
what happens during vernal transitional breeding season
- long irregular periods of receptivity
- 3-4 cycles but no ovulation, will have waves of FSH making follicles but it takes 8-10 weeks of ↑ light to produce enough LH to cause ovulation
During mid to late vernal transition the ovaries will be quite large and contain numerous —
large > 25 mm follicles
Interestingly the transitional follicles are not capable of producing — (steroidogenically incompetent) until about — before the first ovulation of the year.
estrogen
5 days
— is produced by the endometrium day 14 if the mare is not pregnant
PGF2⍺
- Causes luteolysis (luteolysis is the destruction of the CL).
- Causes a marked decrease in plasma progesterone within 5 hours.
- The mare returns to estrus in a few days.
behavior of mare in estrus
- Tolerating copulation (“standing”). This is the most definitive sign that a mare is in estrus.
- Soliciting stallion’s attention.
- Posturing, with characteristic flexed, abducted hind legs and pelvis tilt.
- Raising the tail.
- Rhythmically everting the vulva to expose the clitoris (“winking”).
- Leaning toward the stallion.
- Squatting and urinating (“breaking down”
- Not kicking.
- Neutral position of ears.
behavior of mare in diestrus
- Clamp or swish the tail.
- Kick.
- Move away from him.
- Strike at him.
- Squeal.
- Bite.
- Pin her ears back.
