Placentation

Question 1

what is gastrulation?

Answer 1

the process of a blastocyst turning into a 3-layered entity called a gastrula

Question 2

what 3 layers are present in a gastrula?

Answer 2

1. endoderm
2. ectoderm
3. mesoderm

Question 3

what will the trophectoderm become after gastrulation?

Answer 3

the chorion of the placenta

Question 4

what will the inner cell mass become after gastrulation?

Answer 4

the 3 germ layers of the gastrula

Question 5

which of the 3 germ layers develops first after gastrulation?

Answer 5

endoderm

Question 6

where does the endoderm develop?

Answer 6

around the inside of the blastocoele cavity

Question 7

what forms after the endoderm develops around the inside of the blastocoele cavity?

Answer 7

the yolk sac

Question 8

which germ layer develops after the endoderm and where?

Answer 8

the ectoderm, around the outside of the trophectoderm

Question 9

where does the mesoderm develop?

Answer 9

between the yolk sac and trophectoderm

Question 10

what 7 things will the ectoderm become in both males and females?

Answer 10

1. CNS
2. Sense organs
3. mammary glands
4. sweat glands
5. skin
6. hair
7. hooves

Question 11

what 2 things will the ectoderm become in females?

Answer 11

1. posterior vagina

2. vulva

Question 12

what 3 things will the ectoderm become in males?

Answer 12

1. penis
2. scrotum
3. cowper’s gland

Question 13

what 6 things will the mesoderm become in both males and females?

Answer 13

1. circulatory system
2. skeletal system
3. muscular system
4. reproductive tract parts
5. kidneys
6. urinary ducts

Question 14

what will the mesoderm become in females?

Answer 14

everything internal to the anterior vagina

Question 15

what will the mesoderm become in males?

Answer 15

prostate and everything before

Question 16

what 7 things will the endoderm become in both males and females?

Answer 16

1. digestive system
2. liver
3. lungs
4. pancreas
5. thyroid gland
6. other glands: not all, but many of them
7. primordial germ cells

Question 17

list the 4 placental membranes

Answer 17

1. yolk sac
2. amnion
3. allantois
4. chorion

Question 18

what is the role of the yolk sac in birds?

Answer 18

nourish the embryo

Question 19

what is the role and fate of the yolk sac in mammals?

Answer 19

source of blood cells and PRIMORDIAL GERM CELLS, will atrophy

Question 20

describe the amnion (3)

Answer 20

non-vascular, fluid-filled, smooth

Question 21

what produces the fluid that fills the amnion?

Answer 21

the fetus

Question 22

what is the role of the amnion?

Answer 22

protective cushion, for physical and mechanical protection (like a water balloon)

Question 23

what happens to the amnion at birth?

Answer 23

it ruptures

Question 24

is the amnion still full of fluid when it ruptures at birth?

Answer 24

no, it is almost out of fluid by parturition

Question 25

which placental membrane has vasculature?

Answer 25

the allantois

Question 26

where does the vasculature of the allantois come from?

Answer 26

the fetus

Question 27

what happens to the allantois and what is the result?

Answer 27

fuses with the chorion to form the chorioallantois (or allantochorion), brings blood vessels to chorion

Question 28

what is the chorion? (2)

Answer 28

the outermost placental membrane, the attachment to the mother

Question 29

what takes place at the chorion?

Answer 29

exchange between mother and fetus

Question 30

list the 4 categories of placenta when classifying based on shape or distribution of chorionic villi

Answer 30

1. cotyledonary 2. diffuse 3. zonary 4. discoid

Question 31

list the 3 animals with a cotyledonary placental attachment

Answer 31

1. cow 2. sheep 3. goat (ruminants)

Question 32

list the 2 animals with a diffuse placental attachment

Answer 32

1. pig | 2. horse

Question 33

describe a diffuse placental attachment

Answer 33

like velcro, evenly distributed

Question 34

list the 2 animals with a zonary placental attachment

Answer 34

1. dog | 2. cat

Question 35

describe a zonary placental atatchment

Answer 35

like a belt

Question 36

what animal has a discoid placental attachment?

Answer 36

humans

Question 37

describe a discoid placental attachment

Answer 37

like a plunger

Question 38

what 2 types of cotyledonary attachments are there and which animal has which type?

Answer 38

1. convex: cotyledon wraps around, bovines have | 2. concave: cotyledon burrowed into middle, ovines have

Question 39

what makes a placentome?

Answer 39

cotyledon + caruncle

Question 40

what are BNGCs

Answer 40

binuclear giant cells

Question 41

what do BNGCs do?

Answer 41

migrate from the chorion to the endometrial epithelium in ruminants; invade endometrium

Question 42

what 2 hormones do BNGCs secrete?

Answer 42

1. placental lactogen | 2. pregnancy specific protein B

Question 43

how much of the placenta to BNGCs make up in volume/weight?

Answer 43

about 20% of fetal placenta

Question 44

what are placental lactogens (hormone type and prupose)

Answer 44

protein hormones that have prolactin-like activity to stimulate milk synthesis, and also growth-hormone like activity

Question 45

what animals do NOT have placental lactogens?

Answer 45

pigs and mares

Question 46

what is a possible second function of placental lactogens?

Answer 46

may regulate maternal metabolism to facilitate fetal growth

Question 47

when are there higher levels of placental lactogen and what does this cause?

Answer 47

higher levels in the last 1/3 of gestation, facilitates higher milk production

Question 48

why do dairy cows have higher blood concentrations of placental lactogens than beef cows?

Answer 48

they have been selected to produce more milk

Question 49

what is the role of microcotyledons in a diffuse placents?

Answer 49

increase placental surface area

Question 50

where do the endometrial cups in the mare develop from? (2)

Answer 50

both the trophoblast and the endometrium

Question 51

when do endometrial cups form in mares?

Answer 51

35 d of gestation, AFTER maternal recognition

Question 52

what do the endometrial cups in mares secrete?

Answer 52

eCG, also called PMSG

Question 53

what do the endometrial cups in mares do?

Answer 53

allows the mare to go from one CL to several accessory CLs to increase P4

Question 54

what happens to endometrial cups after 100-140 days?

Answer 54

they are sloughed off

Question 55

what happens to the endometrial cups if a mare loses her pregnancy before days 100-140?

Answer 55

the cups will stay until that time

Question 56

describe the vasculature of a zonary placenta

Answer 56

vasculature focused into chorionic band

Question 57

describe the attachment of a discoid placent

Answer 57

attachment in a big thick disk

Question 58

when classifying based on number of tissue layers, list the 3 types of placenta and the number of tissue layers each has

Answer 58

1. epitheliochorial type (6) 2. endothelialchorial type (4) 3. hemochorial type (3)

Question 59

what animals have epitheliochorial type placentas?

Answer 59

most domestic species

Question 60

list the 6 tissue layers from maternal side to fetal side in an epitheliochorial type placenta

Answer 60

1. endometrial capillary 2. endometrial interstition 3. endometrial epithelium 4. chorial epithelium 5. chorial interstition 6. chorial capillary

Question 61

list the 4 tissue lasyers from maternal side to fetal side of endothelialchorial type

Answer 61

1. endometrial epithelium 2. chorial epithelium 3. chrorial interstition 4. chorial capillary

Question 62

what maternal layers does the hemochorial type placenta have?

Answer 62

NONE HA BITCH

Question 63

what 3 tissue layers does a hemochorial type placenta have?

Answer 63

fetl tissue layers only 1. chorial epithelium 2. chorial interstition 3. chorial capillary

Question 64

does fetal and maternal blood mix during gestation?

Answer 64

NOOOOOOO NEVER

Question 65

when might mixing of fetal and maternal blood occur and what might it result in?

Answer 65

may occur at parturition and may result in antibodies against specific fetal blood type

Question 66

who is affected by the mixing of fetal and maternal blood at parturition?

Answer 66

future neonates or fetuses

Question 67

what is erythoroblastosis fetalis? how treat?

Answer 67

occurs in humans, when antibodies cross the placents, give Rh factor to treat

Question 68

what is neonatal isoerythrolysis?

Answer 68

occurs in cats and horses, carry antibodies in colostrum and are absorbed in the first 24 hours of neonate's life

Question 69

what do you do with isoerythrolysis?

Answer 69

just don't let baby nurse colostrum from mom, once produce milk baby can nurse

Question 70

why do you not have to treat isoerythrolysis to maintain pregnancy?

Answer 70

antibodies don't cross placenta in nonhumans, so only colostrum is affected

Question 71

to what animals does implantation refer?

Answer 71

primates

Question 72

to what animals does attachment refer?

Answer 72

nonprimates

Question 73

list the 3 types of implantation/attachment

Answer 73

1. superficial/centric 2. eccentric 3. interstitial

Question 74

describe superficial/centric attachment and in who it occurs?

Answer 74

chorion lies opposed to uterine wall; in farm animals

Question 75

describe eccentric attachment and in who it occurs?

Answer 75

chorionic sack in a uterine fold, in rodents

Question 76

describe interstitial implantation and in who it occurs?

Answer 76

embryo digests part of uterine wall, embryo burrows into uterus, in humans

Question 77

list the 2 degrees of tissue loss at parturition, and which occurs in what type of attachment/implantation

Answer 77

1. deciduate: high degree of tissue loss, in eccentric and interstitial 2. indeciduate or nondeciduate: low to no degree of tissue loss, in superficial/centric

Question 78

how long can primates bleed after parturition?

Answer 78

for 6-8 weeks