Fertilization, MRP, Placentation Flashcards Preview

RUSVM Theriogenology > Fertilization, MRP, Placentation > Flashcards

Flashcards in Fertilization, MRP, Placentation Deck (38)
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1
Q

__________ is the fertilization of an oocyte by more than one spermatozoon, resulting in embryo death

A

polyspermy

2
Q

T/F: Zygote is unicellular. Embryo is multicellular

A

True

3
Q

After hatching, the conceptus undergoes massive growth. For example, in the cow at day 13 the blastocyst is ~3 mm in diameter. During the next four days, the cow blastocyst will become 250 mm in length and will appear as a __________

A

filamentous thread

4
Q

Which fetal membrane is shown in the picture?

A

amnion

5
Q

Fusion of the male and female pronuclei is termed:

A

syngamy

This is the final setp of fertilization. Following syngamy, the zygote enters the first stages of embryogenesis.

6
Q

Endometrial Cups in the mare produce:

A

equine chorionic gonadotropic (eCG)

helps to luteinize secondary corpora lutea in the mare

7
Q

In all domestic animals, the __________ is the origin of the placenta

A

chorioallantois

8
Q

What is the most accurate blood test you can run in the bitch to detect pregnancy?

A

relaxin

9
Q

Which of the following structures found in the adult mammal do not originate from the embryological mesoderm layer?

  • Gonads and cervix
  • Accessory gland
  • Clitoris and vestibule
  • Ductus deferens
A

Clitoris and vestibule

originate from the ectoderm

10
Q

The functional unit of the placenta is the __________

A

chorionic villi

Villi may be grouped together into microscopic groups (microcotyledons) or macroscopic groups (cotyledons)

11
Q

A cotyledonary placenta is seen in which species?

A

ruminants

Multiple, discrete areas of attachment called cotyledons are formed by interaction of patches of allantochorion with endometrium. The fetal portions of this type of placenta are called cotyledons, the maternal contact sites caruncles and the cotyledon- caruncle complex a placentome. This type of placentation is seen in ruminants

12
Q

What classification of placenta has 5 layers (2 from the mother, 3 from the fetus)?

A

endotheliochorial

dog, cat, ferret

13
Q

What classification of placenta has 6 layers (3 from the mother, 3 from the fetus)?

A

epitheliochorial

cow, ewe, doe, deer

14
Q

In the preattachment development of the embryo, when a distinct cavity is recognizable, the embryo is called a blastocyst. The embryo becomes partitioned into two distinct cellular populations: the __________ and the __________

A

In the preattachment development of the embryo, when a distinct cavity is recognizable, the embryo is called a blastocyst. The embryo becomes partitioned into two distinct cellular populations: the inner cell mass and the trophoblast

15
Q

The process whereby spermatozoa acquire fertility in the female reproductive tract is termed:

A

capacitation

16
Q

What are the three ‘barriers to fertilization’?

A
  • Cumulus cells
  • Zona pellucida
  • Oocyte membrane (oolemma)
17
Q

T/F: MRP in the mare is characterized by a spherical conceptus migrating throughout the uterus

A

True

In the mare, the presence of the conceptus prevents luteolysis. Also, in the presence of the conceptus, endometrial production of PGF2a is significantly reduced. A unique feature of maternal recognition of pregnancy in the mare is that the conceptus inust migrate within the uterus from one uterine horn to the other.

18
Q

A zonary placenta is seen in which species?

A

dogs and cats (and seals, bears, and elephants)

The placenta takes the form of a complete or incomplete band of tissue surrounding the fetus. Seen in carnivores like dogs and cats, seals, bears and elephants.

19
Q

In the preattachment development of the embryo, when a solid ball of cells is formed and individual blastomeres can no longer be counted accurately, the early embryo is called a __________

A

morula

20
Q

A diffuse placenta is seen in which species?

A

horses, pigs, camelids

21
Q

T/F: Zygote is multicellular. Embryo is unicellular

A

False

Zygote is unicellular. Embryo is multicellular

22
Q

What is the mechanism for maternal recognition of pregnancy in the sow?

  • INF-T synthesis
  • Estrogen sulphate production
  • Migration of embryo
  • Only zygote enter the uterus
A

estrogen sulphate production

23
Q

Which one of the following animals is not an induced ovulator?

  • Rabbit
  • Camel
  • Cat
  • Dog
A

dog

24
Q

The conceptus of the pig produces __________ that serves as the signal for maternal recognition of pregnancy

A

estradiol

25
Q

The main driver for the onset of puberty in mammals is:

A

ability of the hypothalamic neurons to produce sufficient GnRH

26
Q

__________ is the ability of a single blastomere to develop into a fully formed individual animal

A

totipotency

27
Q

What happens if maternal recognition of pregnancy does not occur in a timely manner?

A

termination of pregnancy

  • In order for the events of early embryogenesis to continue into an established pregnancy, luteolysis must be prevented. Progesterone must be maintained at sufficiently high levels so that embryogenesis and attachment of the developing conceptus to the endometrium can take place.*
  • If an adequate signal is not delivered in a timely manner, the dam will experience luteolysis, progesterone concentrations will decline, and pregnancy will be terminated.*
28
Q

What four steps must be acheived before the embryo can attach to the uterus?

A
  1. Development within the confines of the zona pellucida
  2. Hatching of the blastocyst from the zona pellucida
  3. Maternal recognition of pregnancy
  4. Formation of the extraembryonic membranes
29
Q

In the preattachment development of the embryo, when a distinct cavity is recognizable, the embryo is called a blastocyst. The embryo becomes partitioned into two distinct cellular populations: the inner cell mass and the trophoblast.

The inner cell mass will give rise to the:

A

body of the embryo

30
Q

A discoid placenta is seen in which species?

A

primates and rodents

A single placenta is formed and is discoid in shape

31
Q

In the preattachment development of the embryo, when a distinct cavity is recognizable, the embryo is called a __________

A

blastocyst

32
Q

After membrane fusion, the oocyte undergoes a series of changes that prepare it for early embryogenesis. The most recognizable is the __________, which prevents penetration by additional spermatozoa

A

cortical reaction

33
Q

T/F: Maternal recognition of pregnancy in the dog and the cat does not necessarily require a signal from the conceptus

A

True

  • The bitch CL has similar lifespan in pregnant and non-pregnant bitches
  • The queen has similar lifespan of CL in pregnant and induced ovulation
34
Q

What protein is produced by the blastocyst in ruminants to signal for prevention of luteolysis?

A

Interferon tau (IFN-T)

IFN-T inhibits the formation of Oxytocin receptors so that Oxytocin can not signal PGF synthesis. IFN also promotes protein synthesis by uterine glands (believed to be critical to preimplantation embryonic survival)

35
Q

In the preattachment development of the embryo, when a distinct cavity is recognizable, the embryo is called a blastocyst. The embryo becomes partitioned into two distinct cellular populations: the inner cell mass and the trophoblast.

The trophoblastic cells will give rise to the:

A

chorion

The chorion will become the fetal component of the placenta

36
Q

T/F: MRP in the sow is characterized by the presence of Interferon tau (IFN-T)

A

False

MRP in the sow is characterized by estradiol, re-routing of PGF2a, embryo elongation, and 4 conceptuses (2 in each horn)

37
Q

The dog and the cat have an endotheliochorial placenta. This placental classification involved complete erosion of the:

A

endometrial epithelium

38
Q

What type of placenta is shown here?

A

Zonary