ANSC 3040 Final Exam Questions with
All Actual Detailed Answers 2026-2027
Updated.
embryonic period of developmental biology - Answer d0-42 in cattle
starts w/formation of zygote after fertilization
- morulation: morula formation by cleavage of zygote
- blastulation: formation of blastocyst, ICM forms embryonic disk, rest if trophectoderm,
conceptus elognates when trophectoderm proliferates
- gastrulation: formation of germ cell layers
ends w/formation of basic structure of organs
fetal period of developmental biology - Answer d43-278 (birth) in cows
growth, maturation, remodeling, of organ systems
do we see elongation in the equine conceptus? - Answer no
what does endoderm form into? - Answer digestive system
lungs
endocrine system
what does mesoderm form into? - Answer muscle
skeleton
cardiovascular
repro system
urinary system
what does ectoderm form into? - Answer nervous system
skin
hair
external parts of RT
what causes variability in body weight at birth? - Answer genetics of dam (contributes to
embryo genetics and uterine physiology) and embryo (influenced by genetics of mother and
father) ex.Brahman in Charolais increases fetus BW
,type of embryo (IVF, cloning)
nutrition and health of dam
maternal maturity
infectious diseases
environmental temperature
gestation length
twins/litter size (compete for nutrients and space)
consequences of variability in body weight at birth - Answer dystocia (too big)
health ex. babies that grow very quickly post-natally are more likely to have cardiovascular
problems in life
performance ex. if too small could have trouble surviving post-partum
carcass traits
functions of placenta - Answer fetal/maternal exchange of nutrients, gases, and waste ex.
glucose (main carb for fetus), acetate (for lipid synthesis)
endocrine organ - produces P4, E2, placental lactogen, glycoproteins, eCG, hCG
physical protection - shock, trauma, disturbance
biological protection - maternal immune system (paternal DNA may cause immune reaction bc
recognized as non-self cell), toxins
components of placenta - Answer embryonic/fetal - extraembryonic membranes, starts to
form before implantation in domestic species
maternal - endometrium, forms by differentiation of endometrial cells during implantation
nutrition of conceptus - Answer pre and peri-implantation: histotroph, becomes a limitation
w/the development of the conceptus bc no direct contact
post-implantation w/functional placenta: haemotroph, allows exchange of nutrients, hormones,
gases, and waste b/w fetal and maternal blood circulation
hemochorial placenta - Answer primates, rodents
no layers on maternal side
3 layers
chorionic villi adhere to endometrium in disc, highly invasive trophoblast break down
endothelium of maternal vessels and maternal blood supply so surrounded by blood
endotheliochorial - Answer degradation of epithelium
, 4-5 layers
bitch, queen
zonary - chorionic villi are concentrated in one section (transfer zone) and go around whole unit
of chorion
pigmented zone, some accumulation of blood, some researchers believe this is important for
iron transfer
synepitheliochorial - Answer 5-6 layers bc maternal and fetal endothelium are mixed
cow, ewe, doe
cotyledonary
epitheliochorial - Answer 6 layers, diffuse, in mare (microzones of chorionic
villi/microcotyledons) and sow (interconnected villi over entire chorion surface)
BNGC - Answer binucleated giant cells
~20% of trophectoderm differentiates into BNGCs, migrates to maternal-fetal interface and fuse
w/maternal epithelium, leading to cotyledon formation
these cells are very active, and excrete PAGs and placental lactogen, which go into maternal
circulation and are associated w/pregnancy survival
PAGs - Answer can be detected using ELISA test to diagnose pregnancy in cows
eCG - Answer secreted by endometrial cups
functions similarly to LH (stimulates CL/P4 secretion)
can induce ovulation of extra follicle during pregnancy, which will form a CL and secrete more
P4
hCG - Answer secreted in primates
has luteotropic activity
secretion starts early in pregnancy, used in pregnancy tests
effects of P4 during pregnancy - Answer stimulates histotroph secretion by uterine glands
inhibit myometrial contractions (P4 block) by keeping oxytocin receptors low
- thought PG expression continues, could lead to pregnancy loss
species w/no secretion of P4 by placenta - Answer queen
bitch
All Actual Detailed Answers 2026-2027
Updated.
embryonic period of developmental biology - Answer d0-42 in cattle
starts w/formation of zygote after fertilization
- morulation: morula formation by cleavage of zygote
- blastulation: formation of blastocyst, ICM forms embryonic disk, rest if trophectoderm,
conceptus elognates when trophectoderm proliferates
- gastrulation: formation of germ cell layers
ends w/formation of basic structure of organs
fetal period of developmental biology - Answer d43-278 (birth) in cows
growth, maturation, remodeling, of organ systems
do we see elongation in the equine conceptus? - Answer no
what does endoderm form into? - Answer digestive system
lungs
endocrine system
what does mesoderm form into? - Answer muscle
skeleton
cardiovascular
repro system
urinary system
what does ectoderm form into? - Answer nervous system
skin
hair
external parts of RT
what causes variability in body weight at birth? - Answer genetics of dam (contributes to
embryo genetics and uterine physiology) and embryo (influenced by genetics of mother and
father) ex.Brahman in Charolais increases fetus BW
,type of embryo (IVF, cloning)
nutrition and health of dam
maternal maturity
infectious diseases
environmental temperature
gestation length
twins/litter size (compete for nutrients and space)
consequences of variability in body weight at birth - Answer dystocia (too big)
health ex. babies that grow very quickly post-natally are more likely to have cardiovascular
problems in life
performance ex. if too small could have trouble surviving post-partum
carcass traits
functions of placenta - Answer fetal/maternal exchange of nutrients, gases, and waste ex.
glucose (main carb for fetus), acetate (for lipid synthesis)
endocrine organ - produces P4, E2, placental lactogen, glycoproteins, eCG, hCG
physical protection - shock, trauma, disturbance
biological protection - maternal immune system (paternal DNA may cause immune reaction bc
recognized as non-self cell), toxins
components of placenta - Answer embryonic/fetal - extraembryonic membranes, starts to
form before implantation in domestic species
maternal - endometrium, forms by differentiation of endometrial cells during implantation
nutrition of conceptus - Answer pre and peri-implantation: histotroph, becomes a limitation
w/the development of the conceptus bc no direct contact
post-implantation w/functional placenta: haemotroph, allows exchange of nutrients, hormones,
gases, and waste b/w fetal and maternal blood circulation
hemochorial placenta - Answer primates, rodents
no layers on maternal side
3 layers
chorionic villi adhere to endometrium in disc, highly invasive trophoblast break down
endothelium of maternal vessels and maternal blood supply so surrounded by blood
endotheliochorial - Answer degradation of epithelium
, 4-5 layers
bitch, queen
zonary - chorionic villi are concentrated in one section (transfer zone) and go around whole unit
of chorion
pigmented zone, some accumulation of blood, some researchers believe this is important for
iron transfer
synepitheliochorial - Answer 5-6 layers bc maternal and fetal endothelium are mixed
cow, ewe, doe
cotyledonary
epitheliochorial - Answer 6 layers, diffuse, in mare (microzones of chorionic
villi/microcotyledons) and sow (interconnected villi over entire chorion surface)
BNGC - Answer binucleated giant cells
~20% of trophectoderm differentiates into BNGCs, migrates to maternal-fetal interface and fuse
w/maternal epithelium, leading to cotyledon formation
these cells are very active, and excrete PAGs and placental lactogen, which go into maternal
circulation and are associated w/pregnancy survival
PAGs - Answer can be detected using ELISA test to diagnose pregnancy in cows
eCG - Answer secreted by endometrial cups
functions similarly to LH (stimulates CL/P4 secretion)
can induce ovulation of extra follicle during pregnancy, which will form a CL and secrete more
P4
hCG - Answer secreted in primates
has luteotropic activity
secretion starts early in pregnancy, used in pregnancy tests
effects of P4 during pregnancy - Answer stimulates histotroph secretion by uterine glands
inhibit myometrial contractions (P4 block) by keeping oxytocin receptors low
- thought PG expression continues, could lead to pregnancy loss
species w/no secretion of P4 by placenta - Answer queen
bitch
