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PHYSIOLOGY III > L7: Pregnancy and Parturition > Flashcards

L7: Pregnancy and Parturition Flashcards

1
Q

meiosis II occurs at _______

A

fertilization

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2
Q

the LH surge prior to ovulation allows the meiotic arrest in the _______ follicle to be lifted

A

dominant

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3
Q

prior to ovulation, oocytes are in _______ arrest

A

meiotic

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4
Q

prior to ovulation, what keeps oocytes in meiotic arrest?

A
  • Oocyte inhibiting factor keeps oocytes in prophase I
  • Luteinizing inhibiting factors prevents granulosa cells from becoming luteal tissue
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5
Q

removal of the oocyte from ______ cells at ovulation releases the inhibition of ________

A

follicle
meiosis

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6
Q

sperm motility in the cervical canal requires an _______ pH

A

alkaline

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7
Q

sperm transportation within the uterus is assisted by ___________, facilitated by estrogen

A

myometrial contractions

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7
Q

what makes the cervix mucous watery, facilitating sperm motility

A

estrogen

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7
Q

upon reaching the ovum, sperm have to get through what two barriers

A
  • corona radiata
  • zona pellucida
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8
Q

Upon movement through female reproductive tract, sperm _______ occurs

A

capacitation
exposure of acrosomal cap

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9
Q

the semen has _______ in its ejaculate which helps move sperm within female reproductive tract

A

prostaglandins

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10
Q

ZP3 binding to ZP3 receptors initiates the _____ reaction

A

acrosomal

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11
Q

ZP___ serve to hold the sperm in place

A

ZP2

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12
Q

what is the zona reaction

A

occurs once a sperm penetrated the ZP
a fertilin on the sperm binds fertilin receptors (integrins) on the egg surface to cause in influx of Ca+ into the ovum
Ca+ influx causes depolarization and release of cortical granules to harden the ZP, blocking the entry of other sperm (polyspermy)

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13
Q

fertilization occurs within the ______

A

oviducts (fallopian tubes)

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14
Q

what prevents luteolysis in the cow and ewe

A

INF-τ
released from trophoblast

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15
Q

what does INF-τ do

A

blocks oxytocin receptors in the uterus, inhibiting the synthesis of PGF2α, thus pregnancy is recognized

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16
Q

oxytocin signaling induces a positive feedback loop causing rapid ______

A

luteolysis

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17
Q

In sows, _______ from the trophoblast serves as the signal to recognize pregnancy

A

Estrogen
this causes PGF2α to be recouted back to the uterus lumen and does not signal the CL

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18
Q

maternal recognition must occur before ______

A

luteolysis

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19
Q

luteal _____ stimulates the endometrium to secrete _______ in non-pregnant females

A

oxytocin, prostaglandin

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20
Q

prostaglandin secretion is _______ is there is an embryo present

A

suppressed

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21
Q

what hormone remains high during pregnancy

A

progesterone

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22
Q

in the mare, ______ has an LH like effect that are released from the uterus, signal to the ovary to keep the corpus luteum open

A

equine chorionic gonadotropin (eCG)

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23
Q

_______ is released by the endometrial cups of the placenta at ~40-70 days of pregnancy

A

Equine Chorionic Gonadotropin (eCG)

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24
Q

in mares, this hormone enchances progesterone production by the primary CL and triggers ovulation of additional follicles to create a secondary CL

A

equine chorionic gonadotropin (eCG)

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25
Q

in dogs, ____ function begins autonomously and is supported by LH, followed later by _______

A

luteal, prolactin

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26
Q

in the dog, ____ enhances luteal activity, it is produced by either the CL or placenta depending on species. This enhances progesterone

A

relaxin

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27
Q

in cats, _____ and progesterone maintains the CL

A

relaxin

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28
Q

in dogs and cats, why is a signal from the embryo not necessary …..

A

CL are not lysed before normal pregnancy

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29
Q

the _______ is an organ of exange b/w maternal and fetal blood

30
Q

what are the two hormones needed to maintain pregnancy

A

estrogen and progesterone

31
Q

acts as a transient endocrine organ that secretes essential pregnancy hormones (E and P)

32
Q

in cows, ewes and mares, the placenta takes over for the ______ in maintaining pregnancy (takes over P production)

33
Q

progesterone inhibits __________ and maintains pregnancy

A

myometrial contractions

34
Q

as progesterone progresses, the number of progesterone receptors _______

35
Q

Describe the zona reaction

A
  • sperm penetrates zona pellucida
  • a fertilin on sperm can bind fertilin receptors on egg surface
  • influx of Ca into ovum
  • Ca causes depolarization and AP
  • release of cortical granules that harden the ZP and blocks further ZP signaling, prevents polyspermy
36
Q

in most domestic animals, implantation occurs after several _______, during which time, significant ________ development occurs

A

weeks, embryonic

37
Q

oxytocin signaling induces a ______ feedback loop causing rapid _______

A

positive
luteolysis

38
Q

in cows and ewes, _______ are released from the trophoblast and block _____ receptors in the uterus, inhibiting the synthesis of ______, thus pregnancy is recognized

A

INF- τ (interferons)
oxytoxin
PGF2alpha

39
Q

in cows, serum _____ is a reliable marker of conception at days 17-20 post ovulation

40
Q

in sows, ________ from the trophoblast seves as the signal to recognize pregnancy

41
Q

luteal _____ stimulates the endometrium to secrete ______ in non-pregnany females

A

prostaglandin

42
Q

when is prostaglandin secretion suppressed

A

if an embryo is present

43
Q

what hormone maintains pregnancy in all species and therefore remains high during pregnancy

A

Progesterone

44
Q

in mares, _______ has an LH like effect

A

equine chorionic gonadotropin (eCG)

45
Q

in mares, ______ is released by endometrial cups of the placenta

A

Equine chorionic gonadotropin

46
Q

immediately after ovulation, _____ from the primary CL decreases, then it is ‘reactivated’ by _______

in mares

A

progesterone
equine chorionic gonadotropin

47
Q

equine chorionic gonadotropin enhances _______ by the primary CL and triggers ovualtion of additional follicles to create _________

A

progesterone
secondary CL

48
Q

how long does the CL survive in dogs (independent of pregnancy)

A

60-70 days

49
Q

in dogs, relaxin enhances _______ activity
and specifically placental relaxin enhances _______

A

luteal
progesterone

50
Q

how long does the CL survive in cats (independent of pregnancy)

A

35-40 days

51
Q

in dogs, luteal function begins autonomously and is supported by ______ followed later by ________

A

LH
Prolactin

52
Q

in cats, the _________ unit influences and extends luteal activity

A

fetal placental

53
Q

in cats, ______ and ________ maintain the CL

A

relaxin and progesterone

54
Q

implantation occurs when the endometrium is at peak __________ and secretion

55
Q

blastocyst implantation begins when cell adhesion molecules adhere to the _______ and trophoblast enzymes erode the __________

A

endometrium
uterine wall

56
Q

steps in implantation

A
  1. blastocyst adheres to endometrial lining
  2. trophoblast cells invade the endometrium
  3. blastocyst is completely buried in endometrium
57
Q

what hormones does the placenta secrete

A

equine chorionic gonadotropin
estrogen
progesterone

58
Q

in cows, ewes and mares, the ______ takes over for the CL in maintaining gestation

59
Q

progesterone inhibits myometrial __________

A

contractions

60
Q

__________promotes the endometrial gland growth, stimulates the activity of the oviduct and endometrial glands to provide nutrients

A

progesterone

61
Q

in ruminants and sows, ________ increases dramatically at the end of pregnancy

62
Q

how does estrogen inhibit lactation in ruminants and sows

A

antagonizes prolactin - effect on mammary glands, suppreses milk synthesis
inhibits lactalbumin - required for lactose synthesis

63
Q

what occcurs during stage I of parturition

A

progesterone is converted to estradiol
luteolysis
PGF2alpha contributes to myometrial contractions
preparation of birth canal

64
Q

what occurs during stage II of parturition

A

delivery, fetus passes through pelvic canal

65
Q

what occurs during stage III of parturition

A

fetal membranes are delivered, myometrial contractions help reduce uterus size and release of membranes (PGF2alpha surge)

66
Q

what initiates stage 1 of parturition

A

fetal adrenal corticoids

67
Q

what controls the timing of birth

A

fetal cortisol levels
as fetal cortisol levels rise, progesterone levels fall

68
Q

what are the 2 main things fetal cortisol does

A

activates 17α-hydroxylase to cause synthesis of estrogen rather than progesterone

Causes placenta to produce PGF2α; CL regresses

69
Q

what are the effects of fetal cortisol activating 17α-hydroxylase

A
  • synthesis switches from making progesterone to estrogen
  • causes myometrium to become more active
  • increases secretory activity of the reproductive tract and opens the cervix
70
Q

what are the effects of fetal cortisol causing the placenta to produce PGF2α

A
  • CL of pregnancy regresses
  • stimulates synthesis of relaxin (loosens/softens birth canal)
  • directly stimulates myometrial activity
71
Q

Stage II of parturition is mediated by _______ signaling

72
Q

when is labor initiated

A

when oxytocin receptor concentration reaches a critical threshold

73
Q

what is pitocin

A

pharmalogical synthetic form of oxytocin

PHYSIOLOGY III (31 decks)

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