Things We Were Told Will Be On The Exam Flashcards
what does the primordial follicle look like?
- oocyte
- FLAT granulosa cells! egg surrounded by layer of flattened follicular cells and basement membrane around it so it is distinct
what does a primary follicle look like?
- larger oocyte
- zona pellucida formed around oocyte
- CUBOIDAL granulosa cells: single layer
induced ovulation
- follicular development stimulated by FSH
- estrogen levels increase, simulating estrus
- COITUS INDUCES LH SURGE
- ovulation-inducing factor in semen!! nerve growth factor B!!
ovulation inducing factor in semen
nerve growth factor B: camelids! induced ovulators!!
what is unique in dogs about progesterone production?
- in most species, progesterone levels begin to increase 1-2 days AFTER ovulation
- in the dog, progesterone levels rise PRIOR to ovulation
- LH surge causes rise of progesterone which is the trigger for standing heat: won’t go into heat until progesterone is high!
what is the most luteotropic hormone in domestic animals?
LH: CL function is maintained by pulsatile LH release
transfer of PGF2a (prostaglandins) from the uterus to the ovary occurs by either
- local counter-current system: ruminants
- PGF secreted into vascular bed, vein leaving uterus heads opposite direction as the artery heading up to ovary. get prostaglandin hormone exchange: transfers PGE to artery and thus destroys CL there - general systemic circulation: horses and pigs
why does a CL need to be present on the same side where you want to establish pregnancy?
need to transfer embryo into heifer on the SAME SIDE as her corpus luteum so the pregnancy tells the endometrium NOT TO RELEASE PROSTAGLANDINS because those will destroy the CL and the embryo will fade away
in the dog, what is the difference in the amount of progesterone in the luteal phase of pregnant vs non pregnant animals?
there is no difference: from a CL in a dog that has ovulated and is pregnant vs ovulated and not pregnant, the amount of progesterone is indistinguishable and you cannot use progesterone to say if an animal is pregnant or not pregnant
how can a CL be prolonged in LA?
chronic uterine infection!! difference of pyometra in dog/cat vs cattle
pyometra in large animal = chronic, big fluid accumulation with enough damage to uterus that they will not release prostaglandins and will have a retained CL!
what can cause premature luteolysis?
- PGF2a administration
- endometritis: acute inflammation causing premature PGF2a release
cows and horses that are short cycled (ie, you were expecting them to come into heat in 18 days but they come in at day 6) are
INFECTED! short estrous cycles (short luteal phases) in a LA suggests presence of a uterine infection
endometritis causes PGF release from cells
what are the side effects of progestins in dogs? (medroxyprogesterone acetate aka depo provera)
- MAMMARY NEOPLASIA!!
also weight gain, adrenal suppression, mild lethargy
zona pollucida vaccine action on cycles
- antibodies against ZP proteins block sperm binding sites
- does NOT BLOCK ESTRUS OR BLOCK OVULATION!! animals continue to cycle!!
cystic ovaries in cows
- cow and sow, esp dairy cows early postpartum
- persistent >10 days follicle >25 mm is considered anovulatory/cystic follicle
an acute infection will cause a shortened/prolonged luteal phase
shortened: caused by prostaglandin release from endometrium because of acute inflammation. will short cycle
a chronic infection will cause a shortened/prolonged luteal phase
prolonged: failure of adequate prostaglandin release from endometrium because of loss of endometrial function
what sex cord stromal tumor is common in animals/horses
granulosa cell tumor: hormonally active
test for AMH, inhibin, testosterone
see behavioral changes like stallion behavior
