Placentation, Gestation, Parturition Flashcards

(41 cards)

1
Q

Placenta

A

Organ of physiologic exchange

  • fusion of fetal membranes to endometrium
  • size/functions change with pregnancy stages
  • expelled after parturition (stage 3)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Placenta is classified based on

A

Gross shape and distribution of villi

- microscopic structure of feto-maternal barrier

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Villi function

A

Bring fetal vessels into close proximity to maternal blood vessels

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Diffuse

A

Attached everywhere

- mare and sow

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Cotyledonary

A

Attachment occurs in small, multiple focal areas

- ewe, doe, cow

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Zonary

A

Attachment occurs in a specific circular zone around the fetus
- bitch and queen

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Discoid

A

Attachment occurs in one large single area (large cotyledon)

- primates and rodents

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Convex villi

A

Cow, giraffe

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Concave villi

A

Sheep, goat

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Fetal _____ fuse with maternal ______ to form ______

A

Cotyledons; caruncles; placentomes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Maternal caruncles

A

Specialized projections of uterine mucosa

- convex in cow, concave in ewe/doe

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Functional unit

A

Placentome

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Utero verdin

A

Dark green fluid

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Binucleate giant cells

A

Move from fetal side across junction, into maternal side to secrete substances (pregnancy specific protein B) that are used to detect pregnancy
- basis for pregnancy blood test

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Epitheliochorial

A

Least intimate, both maternal and fetal epithelium are intact

  • greatest barrier
  • pig, horse, cow, ewe, doe
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Endotheliochorial

A

Complete erosion of endometrial epithelium

- dog, cat

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

Hemochorial

A

Chorionic epithelium is in direct apposition to maternal pools of blood

  • intimate, close attachment
  • primates, rodents
18
Q

Degree of invasiveness is important for transfer of _____

A

Maternal antibodies

- need to colostrum is high in pigs, cows, ewes

19
Q

Deciduate

A

Portion of endothelium is shed with placenta

- dog, cat, rodents, primate

20
Q

Adeciduate

A

Endometrium is left intact at time of placenta expulsion

- pig, cow, horse, sheep, goat

21
Q

Placental functions

A
  • metabolic exchange

- substitutes for fetal GIT, lung, kidney, liver, endocrine glands

22
Q

The placenta produces hormones that _____

A
  • stimulate ovarian functions
  • maintain pregnancy
  • stimulate mammary function
  • assist in delivery of fetus
23
Q

In which species does the placenta NOT have a role in pregnancy maintenance?

A
  • bitch
  • queen
  • camels
  • sow
  • doe
24
Q

The placenta takes over from primary (ovarian) source of progesterone in _______

A

Cow, ewe, and mare

  • cow: 6-8 mos
  • ewe: 50 days
  • mare: 70 days
25
Endometrial cups are unique to the _____
Mare - produce equine chorionic gonadotropin - temporary structure - embed and invade maternal endometrium - could measure eCG level to determine pregnancy (is highest around 80 days)
26
Placental circulation
2 circulations parallel to each other - blood does not intermingle between dam and fetus - close enough for gas and nutrient exchange to occur
27
Freemartinism
Blood can be co-mingled between twins of cattle but rarely of other species - anastomosis of fetal circulation - mascinulizes female = sterility
28
What species has the most variable gestation length?
Mare | - 340-360 days
29
Placental takeover of P4 production in the cow and mare
150 days
30
Gestation lengths
- cow: 283 days - ewe: 152 days - doe: approx 230 days - sow: 114 days - dog: 58-68 days - cat: 64-67 days - camelids: 11 months
31
Amniotic fluid
- origin: fetal urine, secretions from respiratory and buccal cavity, maternal circulation - functions: protects fetus from external shock, prevents fetal skin adhesion to membrane, dilates cervix and lubricates birth passage
32
Allantoic fluid
- origin: fetal urine, secretions of allantoic membrane - functions: brings allochorion into close apposition with endometrium, stores fetal excretory products not transferred to mother, maintains osmotic pressure of fetal plasma
33
Fetal fluids
Function to protect and bathe the fetus - lubricate birth canal - elimination of waste - maintains osmotic pressure of fetal plasma, prevents fluid loss to maternal circulation
34
Hippomanes
Allantoic calculi, similar to bladder stones - do not serve physiologic purpose - seen occasionally in cattle, common in equines
35
Stage 1 of parturition
Initiation of myometrial contractions - P4 block has been removed via PGF - P4 converted to E2
36
Stage 2
Expulsion of fetus | - strong myometrial and abdominal contractions expels fetus
37
Stage 3
Expulsion of fetal membranes
38
Active straining is due to
Abdominal contractions
39
Fetal stress drives the ____
Parturition cascade
40
Myometrial contractions
Uterus is transformed from P4 dominated "relaxed" state to an "active" state - PGF synthesis and release is increased - act jointly to initiate uterine contractions needed to dilate the cervix and deliver the fetus
41
Immune stats
Fetus synthesizes little to no antibodies - acquires antibodies from dam while in utero (rat, human) - secretes antibodies in colostrum (farm animals) - related to impermeability of epitheliochorial placenta to antibodies