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154 Cards in this Set
- Front
- Back
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What is the average length of time for a non-pregnant cow's cycle?
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21 days (18-24 days normal range)
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How long does proestrus last?
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3-4 days
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When does proestrus begin?
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With the completion of leuteolysis
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What happens to progesterone levels during proestrus?
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Rapidly declines
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What happens to estradial and LH levels during proestrus?
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They increase
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What effect does estrogen have on LH during proestrus?
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Induces ovulatory LH surge
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How long does the LH surge last?
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8-12 hours
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The estrogen peak and LH surge are at the onset of which stage of the cycle?
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Estrus
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How long does estrus last?
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12-18 hours
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At estrus, what happens to estrogen levels?
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Declines
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In the cow, when does ovulation occur?
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24-30 hours after the onset of estrus.
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What type of vaginal discharge is seen during estrus?
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Clear mucus discharge
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Metestrus, in a cow cycle, is also known as what part of the cycle?
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Period fo corpus hemorrhagicum
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During metestrus, how high must the levels of PGF2a be to affect he corpus luteum?
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Cl is not responsive to PGF2a thru day 5 of the cycle
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The mature CL produces what chemical?
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Progesterone
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During metestrus in a cow cycle, what type of vaginal discharge is seen?
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Bloody (occurs after ovulation)
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The metestrus bleeding in the cow comes from where?
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The uterus
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Diestrus, in a cow cycle, is also referred to as what phase?
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Luteal phase
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Diestrus, in the cow cycle, is from what day to what day?
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Day 4-5 until luteolysis at day 16-18 after onset of estrus
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In the non-pregnant cow, what chemical is responsible for luteolysis?
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PGF2a
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In the non-pregnant cow, PGF2a is secreted from where?
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The uterus
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With the secretion of PGF2a, what happens to progesterone levels?
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Immediate drop in P4 levels
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In the cow, what prevents the PGF2a surge?
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Presence of an embryo
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Giving cows a pharmaceutical dose of PGF2a mimics what?
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The onset of proestrus
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In the cow, how does PGF2a released from the uterus reach the ovary?
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By the local ipsilateral route
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When a does of PGF2a is given to a herd of cows what effect will it have on cows in diestrus?
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They will respond and move to proestrus
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How would you syncronize the rest of the herd?
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Give another does at day 11
(first group will be in diestrus) |
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After ovulation in the cow, the corpus luteum develops from where?
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The follicle wall
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Granulosa cells differentiate into what type of cells?
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Large luteal cells
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Large luteal cells produce how much of the P4 needed to sustain pregnancy?
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70%
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Small luteal cells are differetiated from which cells in the cow?
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Theca cells
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What hormone is needed for maximum P4 secretion by the theca cells?
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LH
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PGFS 2a is synthesized where in the cow?
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Uterine epithelium
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Progesterone and progesterone receptors block expression of which receptors?
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Estrogen receptors
Oxytocin receptors |
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What effect does long term progesterone exposure have on progesterone receptors?
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Downregulates the receptors
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Where is oxytocin produced in the cow?
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Pituitary and CL
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In the cow, where does oxytocin bind?
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On the uterine luminal epithelium and superficial uterine gland epithelium
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How is PGF2a transferred from the uterine vein to the ovarian artery in the cow?
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The vein and artery are wrapped together
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In which hoofed species is this local ipsilateral movement of PGF2a NOT seen?
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Horses
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In the mare, how does PGF2a reach the ovary?
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Via the systemic route
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The conceptus in the cow produces what chemical which prevents the development of the luteolytic mechanism?
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IFN-tau
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What is meant by "maternal recognition of pregnancy?"
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The physiological process whereby the conceptus signals its presence to the maternal system & prolong the lifespan of the CL
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What is meant by the term "conceptus?"
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all tissues derived from the developing zygote/morula/blastocyst/embryo...embryo/fetus and placenta and assoc. tissues
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For the maternal system to recognize the conceptus, an embryo must be located where by day 16 post estrus?
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In the uterine horn ipsilateral to the ovary that containd the CL
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What part of the conceptus synthesizes IFN-tau?
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Conceptus trophectorderm
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In sheep, IFN tau has what effect?
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Suppresses transcription of estrogen receptors, prevents release of PGF2a
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What is the effect of PGF2a in hoofed animals?
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Luteolysis
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Where is PGF2a formed in hoofed animals?
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Uterus
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In the cow, PGF2a reaches the CL how?
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By local route
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In which species does PGF2a reach the CL by a systemic route?
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Mares
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What native PGF2a drug is used in vet med?
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Lutalyse
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What is Cloprostinol?
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A synthetic analog of PGF2a
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What are the 4 uses of PGF2a in vet med?
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-luteolysis- shorten duration of diestrus
-abortion- via luteolysis -treatment of pyo-muco-hyrdo-metra -induction of partuition (cow, sow) |
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Other prostaglandins have what uses?
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-opthalmic
-human obstetrics- induction of labor -human abortion |
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What safety precaution should be take when handling PGF2a?
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Women should not handle PGF2a
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Where is the endogenous source of GnRH located?
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Hypothalamus
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GnRH, transported to the pituitary causes the release of what?
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FSH and LH
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What type of molecule is GnRH?
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Decapeptide
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What effects does GnRH have?
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-initiate and maintain follicular growth via FSH and LH
-stimulate ovulation -act as luteotrophic agent (via LH) -maintain spermatogenesis and androgen levels via LH |
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GnRH can be used to treat what disease condition?
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Cystic ovarian disease
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How is GnRh used in vet med for breeding management?
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-stimulate follicular development
-stimulate ovulations (to match AI) -aid in causing additional ovulations -increase spermatogenesis and libido in laes. |
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WHich GnRh drug is commonly used in vet med?
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Cystorelin
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Oxytocin is a peptide composed of how many amino acids?
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9
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Where is oxytocin synthesized and transported?
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Synthesized in the hypothalamus, transported to posterior pituitary
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From where else is oxytocin produced?
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Corpus luteum and endometrium
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Oxytocin is similar in structure to what other hormone?
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ADH
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What effects does oxytocin have on the body?
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-myometrial contractions
-milk let-down -paticipates in luteolysis -influences socail, sexual and maternal behaviors |
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True or false. Exogenous oxytocin is packaged in convenient, small doses?
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False, high concentration
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What effect does oytocin have on the uterus during partuition?
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stimulates uterine contractions
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In which species is oxytocin used to initiate partuition?
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Mares
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Why is oxytocin given after partuition?
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To empty the uterus of fluids
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Oxytocin is used to stimulate milk let-down, esp in which species?
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Sows
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Why is oxytocin given to males, esp equines>
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To stimulate sexual arousal and cause passage of sperm blocking the ampulla
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Oxytocin and vasopression are key jormones is influencing what behaviors?
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Pair bonding and monogamy in some species
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What is the pre-cursor for Progesterone and other hormones?
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Cholesterol
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Progesterone has how many carbons?
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21
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Which hormone is formed from progesterone but pared down to 19 carbons?
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testosterone
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Testosterone is a precusor for estradiol which has how many carbons?
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18
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Progesterone is produced where?
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Corpus luteum and placenta
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What are the primary uses of progesterone in vet med?
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-mimic the luteal phase
-suppress estrus -support pregnancy -induce mammary development |
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What progesterone product is available for use in dogs?
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Ovaban
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Ovaban has what 2 uses in vet med?
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-postpone estrus
-dermatological conditions in feline |
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What product is available for use in horses and pigs?
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Regu-mate
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What progesterone drug was used in humans, and was used in dog for contraception?
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Depo-Provera
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What is the purpose of using progesterone to mimic the luteal phase?
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-to delay heat
-to treat anestrus, cystic ovarian disease, puberty -to synchronize estrus |
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How does progesterone work as a contraceptive drug?
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-delays estrus
-in humans, prevents ovulation |
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In dairy cows, progesterone is given to have what effect?
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Induce lactation
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Which subunit of FSH determines its activity from LH and TSH?
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Beta subunit
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Where is the endogenous source of FSH?
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Anterior pituitary
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Secretion of FSH is inhibited by what substance?
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Inhibin
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What 2 effects does FSH have?
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-initiates maturation of pre-antral follicles
-initiates Sertoli cell function for spermatogenesis |
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What is FSH used for in vet med?
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-stimulate ovarian function
-superovulation for embryo transfer -promote spematogenesis |
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What is the source of exogenous FSH?
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-purified pituitary extract
-eCG |
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What effects does LH have on follicles?
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-causes oocyte activation
-ovulation -luteinization |
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What effect does LH have on testosterone production?
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Stimulates production by Leydig cells
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What type of molecule is LH?
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Glycoprotein
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Where is the endogenous source of LH?
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Anterior pituitary
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The release of LH is inhibited by what condition?
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Low concentrations of P & E
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What causes the release of LH?
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Estrogen spike
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Lh binds to the receptors of the CL, stimulating production of what?
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Progesterone
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What effect does LH have on the follicle?
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Stimulates ovulation
Activates pre-ovulatory oocyte |
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How is LH used in vet med?
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-induce ovulation in mares
-treat cystic ovarian disease in cows |
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What is the source of exogenous LH in vet med?
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-hCG
-pituitary extracts |
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What organ produces eCG?
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Equine placenta
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In other animals, eCG has what type of effects?
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Strong FSH effects
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What effects does eCG have in the mare?
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-stimulates luteinization
-maintains Cl activity -promote production of progestins |
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What type of molecule is eCG?
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Glycoprotein
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What FSH effects does eCG have in other animals?
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-reduce post partum anestrus in pigs
-induction of puberty -increase ovulation rate in small ruminants -induce estrus in dogs and exotic mammals -superovulation in cattle |
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What eCG products are available in vet med?
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PMSG-generic pregnant mare serum gonadotropin
PG600: combo of eCG and hCG |
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What organ produces hCG?
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Human placenta
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What type of acitivity does hCG produce?
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LH
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hCG is used extensively in all domestic species to do what?
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Induce ovulation
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In which species does hCG work well?
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Equine
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FSH, LH, hCG and eCG are large protein molecules. What does this mean in terms of handling and storage?
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Will degrade if kept at room temperature
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What type of reaction might occur from repeated use?
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Immune reaction
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What other considerations must be gien when using these drugs?
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Derived from animal tissue or blood, could have other biologically active substances, infectious agents.
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Testosterone is produced where? And is a precusor for what other hormone?
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Produced in the testis, precusor for estrogens
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Which form of testosterone is the more androgenically active form in males?
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Dihydrotestosterone
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What is the name of the oral form of testosterone?
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Methyl-testosterone
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What testosterone product is used as a canine contraceptive?
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Mibolerone- cheque-drops
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How is testosterone used in vet med?
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-to make teaser cows for estrus detection
-keep racing greyhounds out of heat |
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What organs produce estrogens?
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Ovarian follicles and placenta
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What behavior do estrogens cause in females, in the absence of progesterone?
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Estrus behavior
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What other effects does estrogen have in females?
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-changes in the uterus and vagina
-leads to release of GnRH and LH leading to ovulation |
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What is the name of the drug that is the oral form of estrogen?
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DES-diesthylstilbestrol
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What product is used to synchronize a cattle herd?
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Synchro-mate
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In dogs and cats, estrogen injections can be given for what?
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Mis-mating
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Post partum, estrogen has what effect on the uterus?
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-increases motility for clearance
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In which species is estrogen used to treat urinary incontinence?
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Spayed dogs and cats (DES)
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What effects can estrogen have in cows?
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-luteolysis
-abortion |
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In the dog, estrogen is used for what?
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Initiate proestrus and estrus
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Overdosing might have what effect in dogs?
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Toxic- bone marrow suppression
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The period of metestrus, in other animals, takes place when in the dog?
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During estrus
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During estrus, what are the levels of estrogen?
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Low
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What is happening to P4 during estrus?
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Rising
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The proliferation of vaginal epithelium with a thick layer of superficial cells cannot be supported past...when?
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Past 8-9 days post LH peak
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What cells start to predominate in late estrus?
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Superficial cells are lost, parabasal and intermediate cells predominate in smear
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With the loss of the superficial cells, what cells migrate through the epithelium?
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PMN's to kill bacteria
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The date of the onset of estrus can vary depending on which point it is measured from. The 2 possible points of measurement are...
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LH surge
Onset of cytological diestrus |
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Estrus in the dog is defined as what behavior?
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Standing to be mounted
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Canine sperm can live for how long in the estrus canine uterus?
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1 week
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When us the optimum fertilization time for single matings?
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4 days before cytological diestrus
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Mating that takes place 4 days before cytological diestrus, is taking place how many days after the LH peak?
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5 days after LH peak
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A conception rate of 90% is still achieved when mating is on what day?
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6 days after LH peak or
8-10 days before cyto diestrus (which is day before LH peak until 6 days after LH peak) |
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Pups produced per corpus luteum is over 80% during mating at what time?
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10 days until 4 days before D1
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When is the peak (96%) fertilization period?
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D1 minus 4
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Why might the length of gestation vary in dogs?
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If a dog gets pregnant from breeding a couple of days before the LH peak all the way out until the week beyond LH peak, gestation length will vary whenever the date of breeding is used as a starting point of gestation.
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Does gestation begin with breeding or with fertilization?
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Fertilization
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If fertilization is 4 days before D1, whelpings will be close to how many days of cyto diestrus?
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57 days
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When using the LH peak or D1 as the start of gestation, do small or large litter sizes have longer gestation?
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Smaller litters
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What is another term for pseudopregnancy?
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Galactorrhea, pseudocyesis, false pregnancy
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How is pseudopregnancy defined?
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Lactation at end of diestrus in non-pregnant bitch
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What are the difference in P4 levels between a pregnant, and non-pregnant dog with pseudopregnancy?
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No difference
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What types of drugs resolve pseudopregnancy?
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None needed but...antiprlactin drugs (cabergoline), androgens, progestins
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