Placentation

Question 1

the placental has 2 components, 1. the fetal part that develops from the __ and 2. the maternal part that is derived from the __

Answer 1

chorionic sac, endometrium

Question 2

the placental has a selective __ that does __ prevent crossing of certain viruses, toxins, parasites

Answer 2

placental barrier, NOT

Question 3

the placenta is an __ organ secreting hormones necessary for __

Answer 3

endocrine, pregnancy

Question 4

progesterone from the placenta

Answer 4

• promotes endometrial growth
• suppresses myometrial contractions
• promotes alveolar development in the mammary gland

CL is the original source in all species

Question 5

estrogen from the placenta

Answer 5

“tissue building”
- myometrial growth and increase uterine vascular proliferation and mammary ductal growth
- estrogen also causes increased sodium reabsorption by mothers kidney renal tubules -> increases blood volume

Question 6

the fetal gonads in horses are grossly __ during gestation as a result of __ precursors

Answer 6

hypertrophied, estrogen

Question 7

placental relaxin from the placenta

Answer 7

present in carnivores and horses to relaxes the cervix, pubic symphysis and ligaments

Question 8

placental relaxin is present in carnivores and horses while in cows, sows, and primates it is partially made by the __

Answer 8

CL

Question 9

histotrophic nutrition

Answer 9

uterine glands -> nutrients -> diffusion-> embryo

chorionic placenta -> yolk sac

Question 10

hemotrophic nutrition

Answer 10

• fetomaternal blood exchange
• allantoic placenta

Question 11

amnion and chorion are made of __ and __

Answer 11

somatic mesoderm and trophectoderm (ectoderm)

Question 12

allantois and yolk sac are made of __ and __

Answer 12

splanchnic mesoderm and hypoblast (endoderm)

Question 13

implantation in the equine is at the junction of the __ with the __

Answer 13

uterine horn, body

Question 14

yolk sac

Answer 14

temporary structure capable of histotrophic nutrition thats important during attachment and a source of primordial germ cells

Question 15

chorion

Answer 15

most external!

• abuts endometrium provides contact between the embryo and external environment
• chorion helps attach early embryo to uterus

Question 16

chorion consists of __ and associated __

Answer 16

trophoblasts (ectoderm), somatic mesoderm

Question 17

amnion

Answer 17

immediately surrounds and contains embryo and amniotic fluid

Question 18

the aqueous fluid provides …?

Answer 18

cushion, movement, prevents adhesion of fetus with amniotic membrane and practice swallowing, gut contractions and breathing

Question 19

allantois

Answer 19

diverticulum of the hind gut

Question 20

allantois in carnivores, horses

Answer 20

tube shaped, grows completely between the amnion and chorion

Question 21

amniotic plaques

Answer 21

normal mineral and sloughed cellular deposits on the surface of umbilical cord or other membrane -> white plaques
-> mostly seen in equine and ruminants

Question 22

Hippomanes (allantoic calculi)

Answer 22

found in allantoic fluid from day 85 with soft concentric layers

Question 23

hydrops allantois

Answer 23

excessive allantoic fluid in cattle and horses

Question 24

hydrops amnion

Answer 24

excessive amniotic fluid

Question 25

olioghydramnios

Answer 25

abnormally low amniotic fluid

Question 26

endometrial cups

Answer 26

Equine only! - normal and temporary during days 35-125 and then regress - certain parts of the chorion detach and invade endometrium - secrete equine chorionic gonadotropin

Question 27

chorionic placenta is __ and is only seen in __ until the allantois is formed

Answer 27

avascular, carnivores

Question 28

the choriovitelline (yolk sac) is retained for longer in the __ than the dog

Answer 28

equine

Question 29

the chorioallantoic placenta is the __ placenta of domestic animals and forms a __ membrane

Answer 29

permanent, trilaminar (trophoblasts, mesoderm, endoderm)

Question 30

the amnion and the chorion __ fuse in the horse and dog and __ fuse in the pig and ruminant

Answer 30

DO NOT, DO

Question 31

in all animals except carnivores the degree of placental invasion into the endometrium is __ meaning it will ___ separate after birth

Answer 31

non-deciduate, easily

Question 32

deciduate placentas are not easily separated because the __ fuse with the erode endometrium

Answer 32

chorionic villi

Question 33

the sow, mare and camelids have a __ placenta that covers the entire surface of the __

Answer 33

diffuse, uterus

Question 34

what is a red bag abortion?

Answer 34

premature placental separation - appearance of the cervical star at the vulva and the enclosed legs of the fetus - the fetus is often delivered within the placenta, with the chorionic side of the placenta still on the outside

Question 35

maternal caruncles + fetal cotyledons = __

Answer 35

placentomes (ruminants)

Question 36

zonary placenta

Answer 36

in carnivores where contact area is ring/belt like band with marginal hematomas providing a source of iron