Embryology Flashcards
The term ecto refers to ____.
outside
The ___ somite will eventually from skin fro the embryo
dermatome
An ovum develops the size of a yolk by collecting lipid particles that were made in the hen’s ___ from the blood
liver
If the hen does not receive enough __ and __ in the feed, she will not make an egg
calcium and phosphorus
When fertilization occurs, embryonic development begins and continues for the __hours that it takes to form an egg in the hen
24 hours
At about __hours of incubation, blood vessels coming from the embryo join with those coming from the area opaca, replacing this area with the yolk sac
48 hours
the extraembryonic membranes are __ of the embryo and never become part of it
outside
Which membrane is visible when a chick first hatches as it lies next to the shell
chorioallantoic
it is expected that more than __ sequences will be discovered in the chicken genome
20,000
formation of the central nervous Sstem is dependent upon the __
neural tube
Less than __ of the chicks with head in wrong part of the egg malposition hatch
One half
all of the parts of a chick are in place by day __ of incubation
10 days
The correct position for a chicken embryo to be in the egg is ___
head tucked under right wing located toward round (large) end of egg
the most common standard for the developing chick embryo was prepared by ___, who divided the standard into 45 stages
hamburger and Hamilton
The neural __ is a region that folds inward to form the neural tube
plate
the inner part of the blastoderm is hollowed out and is ___ indicating that light can pass through it to give is an almost transparent appearance
Pellucida
Another category of defects is called __ in chickens and birth defects in humans
malformations
the outer part of the blastoderm is ___ meaning not much light can pass through
opaca
At about day ___ of incubation, the embryo has used much of the yolk
19
when does cell division begin for the embryo
fertilization
The __ catche steh yolk, which then starts its journey through the oviduct to add the albumen and shell
infundibulum
cell division for the embryo starts from the back of the pellucida and creates a thin layer of cells as it moves in a forward direction, creating a ___
triangle
When the egg is laid, the blastoderm can be compared to a ___
doughnut
A small white dot called the __ is attached to the vitelline membrane and contains the genetics information that is supplied by the female
blastodisc
which of the following is not a function of the chorioallantocia membrane
provide nutrients to the growing embryo
a healthy embryo will cause the egg to have a ___ appearance when candled
red
once a chick hatches, what happens to the solid waste a chick excretes during incubation
remains on the shell
which two factors can impact embryonic development
genetics and nutrients
once the cells have buckled and formed the primitive groove the primitive streak I snow shaped like a ___
pear
one of the membranes that forms soon after incubation which appears as a sac on the outside of the embryo is called the ___
allantois
the term meso refers to ___
middle
as the cells continue to bunch an move toward the middle of the area pellucida on the blastoderm they cause buckling and create a ___
primitive groove
the term ending refers to ___
inside
when the egg is laid and the temperature drops below ___, cell division stops until the egg is brought to incubation temperature
85 degrees
in commercial poultry, the combination of malposition and malformations decrease the overall hatchablility at about __ percent
5%
on of the membranes that is formed soon after incubation and extends around the embryo and lies next to the shell is called ___
chorion
if present, toxic compounds may also enter the egg, either from __ or ___ and these compounds can cause the death of the developing embryo
hen’s feed or egg environment
when the cells on the triangular wedge of the growing embryo bunch toward the middle and form a concentration of cells that is called the ___
primitive streak
during the last few days of incubation when the yolk sac absorbed and the chick begins to breath, an increase in __ muct occur
humidity
producing the right amount of each __ t the right time is what regulates development and life
sugar
the chorion membrane fuses with the allantois membrane to form __
chorioallantoic membrane
what happens to the yolk that is not used by the embryo ?
absorbed in chick’s abdomen
After __ days of incubation, cartilage is present
8 day
in about ___, an ovum develops to the size of a yolk by collecting lipid particles
1 week
the egg must have the proper amounts of about ___ different nutrients for the embryo to develop
40
by day __ of incubation all of the muscle groups present in an adult have been established
10 day
after __ to __ days of incubation, the embryo appears to be floating in a bed of water, which helps prevent injury to the embryo and keeps the embryo bathed in fluid
4-6 days
a very serious malposition is __
head toward pointed end of egg
myotome rom somites 27 through 32 form the __ muscles
leg
by the time the hen lays the egg, enough embryonic cells have formed to be visibly changed, the blastodisc has changed into the ___
blastoderm
the cells of the triangular wedge in the area pellucida move towards the middle of the area in a process called __
gastrulation
yolk contents are retained by the ___
vitelline membrane
the somites exist for only __ days
few
eventually the embryo will have ___ pairs of somites after about ___ hours of incubation
22; 55
what provides the first physical evidence that an egg is fertile ?
blood vessels on the yolk sac seen
one of the membranes that is formed soon after incubation and forms under the embryo and collects water from the albumen is the ___
amnion
There are more than ___ vertebrae in the newley hatched chick, and some vertebrae attach to ribs
40
the area __ is the part of the blastoderm from which the embryo development
pellucida
Having __ is one malposition and it is not as serious
head on outside of head
once the yolk sac is absorbed b the embryo, the __ becomes the main source of nutrition fro the embryo
yolk
cells from they myotome somites form leg Buds between days __ and __
6, 8
if the embryo is not positioned correctly , the condition is known as ___
malposition
the first pair of somites appear at about __ hours of incubation
24
around day __, an increase number of embryos die, with an even larger percentage at day ___
4; 18
the sperm will locate the ___ and penetrate it in the process of fertilization
blastodisc
when the yolk is the correct size, it is released from the ovary to the hen’s ___
abdomen
if the female has mated within the last few weeks , sperm should be present in the ___.
infundibulum
more than ___ specific kinds of defects have been identified, which commonly affect the skeleton, parts of the head, wings, and legs
40
supporting structures called extraembryonic membrane develop mostly in the area __ of the blastoderm
opaca
deficiencies in the hen’s diet such as __ and __ can impact embryonic development
minerals and vitamins
the white spots are __ tat were caused b the sperm that penetrated the egg’s vitelline membrane
bullet holes
An ___ egg has a dark middle caused by the yolk when candled
infertile
