placentation

Question 1

what is intrauterine competition? what is an example?

Answer 1

multiple embryos will implant, only a few will survive.
EX. pronghorn antelope

Question 2

what is placental implantation

Answer 2

-intimate contact of developing embryo with uterine mucosa
-initial sticky attachment between placenta and embryo(immobilization)

Question 3

what type of placental attachment is most evolved

Answer 3

diffuse/less invasive types

Question 4

species variations of placental implantation

Answer 4

-position of implantation site
-invasiveness
-area of contact
-time of implantation(delayed)

Question 5

histotroph nutrition

Answer 5

-stored energy
-mRNA already in cytoplasm
-secreted by uterine glands

Question 6

what is necessary for pre-attachment development

Answer 6

-histotroph nutrition
-embryo and uterine communication

Question 7

syncytial

Answer 7

TCGs invade and engulf luminal epithelium to form syncytial layer

Question 8

what secretes PAGs

Answer 8

Trophoblast giant cells

Question 9

what do trophoblast giant cells form from

Answer 9

differentiate from mononuclear trophoblast cells

Question 10

what is efficiency of transfer across placenta dependent on

Answer 10

uterine and placental size

Question 11

what is selectively transported across the placenta

Answer 11

-amino acids, fatty acids, glucose
-CO2, O2
-Vitamins, minerals, electrolytes

Question 12

functions of the placenta

Answer 12

-nutrient transfer from dam to fetus
-transmission of waste products from fetus to dam
-protection from shock
-hormone production

Question 13

number of layers between fetal and maternal tissue for epitheliochorial placentas

Answer 13

approximately 6

Question 14

number of layers between fetal and maternal tissue for hemochorial placentas

Answer 14

3

Question 14

number of layers between fetal and maternal tissue for endotheliochorial placentas

Answer 14

5

Question 15

T/F pig placenta interacts with the endometrium through interdigitation

Answer 15

FALSE. its through folding

Question 16

what structure is unique to horse placentas that allows it to interact with the endometrium

Answer 16

microcotyledons

Question 17

what are microcotyledons

Answer 17

high amount of placental folding in specific areas

Question 18

T/F placentomes get tighter as pregnancy progresses

Answer 18

TRUE

Question 19

why is it hard to use crown to rump design to estimate fetal age during early pregnancy

Answer 19

fetus is often folded in early pregnancy and unfolds as it grows

Question 20

factors affecting fetal growth

Answer 20

-genetics
-environment
-nutrition
-litter size

Question 21

how does the environment affect fetal growth

Answer 21

placental and uterine size

Question 22

how does nutrition affect fetal growth

Answer 22

smoking
diet

Question 23

factors affecting gestation length

Answer 23

-fetal sex
-litter size
-age of dam
-genetics
-season

Question 24

which sex generally has longer gestation length

Answer 24

male(1-2 days longer)

Question 25

T/F twins have shorter gestation than singles

Answer 25

TRUE(5-10 days less)

Question 26

T/F older dams have longer pregnancies

Answer 26

TRUE(1-2 days longer)

Question 27

length of gestatiopn
-cow
-ewe
-doe
-sow
-mare
-human
-mice
-elephant

Answer 27

cow:9 months
ewe/doe:5 months
sow:3 mo, 3 wks, 3 days
mare:11 months
human: 9 months
mice: 21 days
elephant: 2 years