Others Events During Early Embryogenesis Flashcards
1
Q
referred to as the development of two (2) or more embryos in a dam.
A
Embryonic dumplication or twinning
2
Q
Several causes of embryonic duplication
A
- FERTILIZATION of separately ovulated ova
- COMPLETE or partial separation of blastomeres and blastocysts during cleavage stages
- DUPLICATIONS after gastrula stage when specific organ-forming regions called ‘fields’ are being organized.
- ONE blood supply shared by completely separated twins.
3
Q
derived from a single zygote that eventually divides or duplicates itself.
A
Free Symmetrical Monozygotic Twins/ identical twins
4
Q
type of twins originated from a single zygote (monozygotic).
A
conjoined or fused symmetrical twins
5
Q
result from incomplete separation of blastomeres later in embryonic development
A
primitive streak stage
6
Q
results if the twins are nearly complete
A
diplopagus (two-fold joined)
7
Q
fusion is at the sternal region of the thorax
A
thoracopagus twins
8
Q
fusion is at the abdomen
A
abdominopagus twins
9
Q
fusion is back to back at the pelvis or sacrum
A
pygopagus
10
Q
fusion is in the head region
A
cephalopagus
11
Q
result from duplication of future axial structures which may occur during the primitive streak stage
A
Abnormal twins or monsters
12
Q
two heads
A
dicephalus
13
Q
two tails
A
dicaudatus
14
Q
2 pairs/four pelvic limbs
A
tetrascelus
15
Q
two faces
A
driprosopus
16
Q
two pairs/four of thoracic limbs
A
tetrabrachius
17
Q
this consist of separate twin one is normal and the other is rudimentary that survives by being attached to the blood supply of fetal membranes of the normal twin
A
Free, Asymmetrical Twins
18
Q
it is common in cow
A
mummified fetus
19
Q
twins occur after gastrulation when specific fields are become organized.
A
Conjoined, Asymmetrical Twins
20
Q
type of twinning results when two (or more) zygotes develop separately and independently with separate fetal membranes and placenta
A
Free Symmetrical Dizygotic Twins or Fraternal Twins
21
Q
twins are of different sexes the female twin will have an abnormally developed genital system
A
freemartin
22
Q
membranes develop by folding-off of the embryo during the neurula stage.
A
Extraembryonic (fetal) Membranes
23
Q
forms of the fetal placenta in mammals.
A
Chorioallantoic membrane (CAM)
24
Q
contains the conceptus
A
chronic vesicle
25
4 fetal membranes that develop in a mammalian or avian conceptus
° Amnion
° Chorion
° Yolk Sac
° Allantois
26
two fetal membranes are derived from extraembryonic somatopleure of the blastocyst.
Amnion and Chorion
27
two fetal membranes are derived from extraembryonic splanchnopleure and extraembryonic splanchnic.
Yolk Sac and Allantois
28
source of early nutrition but later shrinks and become non-functional
yolk sac
29
outpocketing of small intestine
Meckel's diverticulum
30
delimits the extent of growth of the splanchnopleure over the yolk.
sinus terminalis or marginal vein
31
most important in egg laying vertebrates
yolk sac
32
short stump of splanchnopleure formed by the folding of the body and closure of the gut tube.
yolk stalk
33
in what stage, the egg albumen losses water due to absorption by the embryo, rapidly decreases in size and is forced to the distal end of the yolk sac by the expanding Allantois.
embryonic development
34
present in reptiles, birds and manmals (amniotes) and absent in fishes and amphibians (anamniotes).
Amnion
35
formed by convergence of the head, lateral and tail folds at the dorsal midline of the embryo
inner sac of extraembryonic somatopleure
36
filled with amniotic fluid in which the embryo floats.
amnion
37
amniotic fluid can contain fetal feces called?
meconium
38
it is formed by fusion of chorioamniotic folds at the dorsal midline of the embryo.
inner sac
39
persist in the chick but may not persist in mammal
chorioamniotic raphe (mesamnion)
40
functions of amnion
° allows free movement of the embryo
° antibacterial
° allows fetal growth
° prevents adhesion of fetal membranes
41
derived from extraembryonic somatopleure. the outer sac that forms the outer boundary of the entire conceptus
chorion
42
consists of an outer surface ectoderm and an inner somatic mesoderm.
chorion
43
ventral diverticulum of the hindgut splanchnopleure.
Allantois
44
become the umbilical vessels
allantoic vessels
45
developing embryo uses oxygen and produces carbon dioxide, i.e. it has respiration.
respiratory
46
Allantois removes the wastes that result from embryo's metabolism and deposits it in the allantoic cavity.
excretory
47
allantois provides the means for the embryo to access the albumen and the calcium of the shell.
digestive
48
present only in placental mammals
placenta
49
membranous structure formed by the apposition of the fetal chorioallantoic membrane and maternal endometrium of the uterus.
placenta
50
food of embryo is uterine milk
histotrophe
51
several functions of placenta
° SELECTIVELY mediates physiological exchange between fetus and mother
° SECRETES hormones like chorionic gonadotropin
° ACTS as a barrier to prevent mixing of fetal and maternal blood.
52
3 layers of fetal placenta
° ENDOTHELIUM of allantoic vessels
° CONNECTIVE tissue composed of somatic mesoderm of the chorion and splanchnopleure of allantois.
° EPITHELIUM composed of the chorionic ectoderm
53
3 layers of the maternal placenta
° EPITHELIUM of endometrium
° CONNECTIVE tissue of endometrium
° ENDOTHELIUM of the uterine blood vessels
54
types of placenta according to the number of tissue layers present between the maternal and fetal blood
1. EPITHELIOCHORIAL
2. SYNDESMOCHORIAL
3. ENDOTHELIOCHORIAL
4. HEMOCHORIAL
55
there is no loss of endometrial tissue during attachment.
Epitheliochorial placenta
56
species that present in the epitheliochorial placenta
horse, pig, cow and partially in goat and sheep
57
ectoderm of chorion is in contact with the connective tissue of the uterine endometrium. The epithelium of endometrium degenerates.
syndesmochorial/ synepitheliochorial placenta
58
the ectoderm of chorion contacts with the endothelium of uterine blood vessels. the epithelium and connective tissue of the endometrium degenerate.
Endochorial placenta
59
Carnivores that present in endochorial placenta
dog, cat, and other canine/feline species
60
the ectoderm of chorion contacts with blood in the uterine blood vessels. all the layers of maternal placenta degenerate.
Hemochorial placenta
61
species present in hemochorial placenta
rodents, primates (monkey), human
62
species present in some parts of the placent in the syndesmochorial placenta
goat and sheep
63
types of placentas according to the shape and distribution of apposition areas between the fetal chorion and maternal endometrium.
1. Diffuse
2. Cotyledonary
3. Zonary - complete or incomplete
4. Discoid - single or double
64
villi are distributed throughout the chorionic vesicle except the undilated ends. Found in horse and pig.
Diffuse placenta
65
villi form tiny oval or around areas called cotyledons
cotyledonary placenta
66
a discrete area of interdigitation between a maternal caruncle and fetal cotyledon.
Placentome
67
villi are concentrated in a wide zone that forms a belt around the chronic vesicle. complete or incomplete
Zonary placenta
68
attach to specific areas, the caruncles, in the endometrium of the uterus.
cotyledons
69
has a belt of villi surrounding the entire chronic vesicle. And found in the dog and cat
Complete Zonary Placenta
70
has a belt of villi that does not completely surrounding the chorionic vesicle. Found in bear, skunk, mink, weasel, ferret and raccoon.
incomplete zonary placenta
71
villi are concentrated in oval shaped disks. Single and Double.
Discoid Placenta
72
has one disk located at one end of the chorionic vesicle. Found in Humans and Rodents.
Single Discoid Placenta
73
has two disks, each located on each side of the chorionic vesicle. Found in Monkey
Double Discoid Placenta
74
uterine endometrium is sloughed of during parturition. Found in Carnivores, primates, human, rodents.
Deciduate Placenta
75
uterine endometrium remains intact during parturition. Found in horse and pig.
adeciduate placenta
76
process in which a developing embryo, moving as a blastocyst through a uterus, makes contact with the uterine wall and remains attach to it until birth.
Implantation
77
an unfertilised egg cell that ovary releases and it travels down the fallopian tube
oocyte
78
an egg is enveloped in an extracellular matrix
zona pellucida
79
prevents the fertilised egg
zygote
80
stage of prenatal development, or the concepts.
blastocyst
81
a process which the zygote moves through the fallopian tube and it undergoes several rounds of cell division.
cleavage
82
one of the few uterine surfaces to which a blastocyst cannot always implant.
endometrium
83
membranes form the fetal portion of the placenta
chorion
84
folds of tissue and blood vessels that connect maternal and fetal blood pools.
chorionic villi
85
Approximately implantation time of Human.
1 week
86
approximately implantation time of dog, cat, sheep.
2 weeks
87
approximately implantation time of deer and bear.
delayed up to 4 months
88
approximately implantation time to horse
3 to 8 weeks.
89
approximately implantation time to cattle
3-5 weeks
90
types of implantation which trophoblast invade and partially destroy the epithelium of the uterine endometrium
interstitial implantation
91
type of implantation which trophoblast do not grow into the epithelium of the uterine endometrium and can be physically separated from the latter
noninvasive implantation
92
gestation period of pig (sus scrofa)
114-116 days (average)
93
gestation period of a Horse (equus caballus)
335-345 days
94
forms around the omphalopleure
sinus terminalis
95
gestation period of Cow (Bos taurus)
279-282 days
96
gestation period of sheep (ovis aries)
148-150 days
97
gestation period of goat (capra hircus)
150 days
98
placenta in bovine are;
Cotyledonary, Epitheliochorial, and moderately diciduate
99
placenta in sheep and goat are;
cotyledonary, partially synepitheliochorial and deciduate
100
is wide and persists throughout pregnancy.
mesamnion
101
result from the proliferation of endometrial connective tissue.
Uterine caruncles
102
gestation period of Dog (Canis familiaris)
63 days
103
gestation period of cat (felis domestica)
60 days
104
gestation period of ferret (mustela potorius furo)
41 days
105
does not develop fully; the amnion which expands and eventually obliterates the extraembryonic coelom.
Allantois
106
gestation of monkey (Macaca mulatta)
160 days
107
fetal placenta is made up of chorioamniotic membranes.
allantoic and placental development
108
gestation period of mouse
18-21 days
109
gestation period of hamster
15 days
110
gestation period of rat
22-23 days
111
gestation period of guinea pig
63 days
112
gestation period of a rabbit
32 days
113
placenta in early stage of development is derived from the ectoderm of chorion and the endoderm of the yolk sac
inverted yolk sac placenta
114
accumulation of excessive amount of fluid in the amnion
Hydrops of the amnion or Allantois
115
associated with some fetal malformation that interferes with it's ability to swallow
hydramnios
116
associated with some disease of placenta causing a vascular disturbance in the endometrium or chorioallantois
hydrallantois
117
species w/ long umbilical cords such as swine, neck or limb strangulation in varying degree may occur.
strangulation by umbilical cord
118
amnion being attached to the embryonic structures particularly the CNS or limbs
Amniotic Bands
