Fertilization typically occurs in the:
ampulla of the oviduct
isthmus of the oviduct
The zona pellucida:
is located between the oocyte and granulosa cells
hardens to provide a block to polyspermy
prevents premature (ectopic) implantation
all of the above
none of the above
Where in the developing embryo is the mesoderm layer absent so that there is no separation bewteen the ectoderm and endoderm layers?
1. oral plate
2. cardiac plate
3. cecal plate
4. lateral plate
1 & 2
2 & 3
Within the trunk of the developing embryo, paraxial mesoderm breaks up into:
thin layers called the intermediate mesoderm
thick layers called the lateral plate
somitomeres consisting of somitomere components
somites consisting of sclerotome, dermatome, and myotome components
During development Meckel's cartilage is known to become a portion of the:
The first branchial arch gives rise to:
muscles of mastication
part of the tongue
muscles of facial expression
a & b
At the beginning of the blastocyst stage there is:
development of a fluid filled cavity called the amnion
formation of an inner cell mass which becomes the trophoblast
formation of an outer cell mass which becomes the embryoblast
At the earliest stage of development the primitive stomadeum is bounded by the (May/ may not be relevant for this exam):
maxillary and mandibular prominences
the frontonasal prominence and mandibular prominence
the frontonasal prominence and cardiac bulge
the median nasal prominences and mandibular process
the maxillary and median nasal prominences and mandibular process
The muscle of the gut wall is embryonically derived from:
lateral plate mesoderm
The mesodermal layer of the embryo:
arose from ectodermal cells of the epiblast
forms blood vessels and most of the heart
forms cartilage and bone
During development the amnion and yolk sac are in temporary communication. This opening is:
Neural crest cells can form or become all of the following except:
olfactory sensory cells
Secretions of epithelial cells of the oviduct:
provide nutritional material for the conceptus
together with cilia establish an outward flow that inhibits bacterial migration toward the peritoneal cavity
produce a current that helps orient spermatozoa
Progression from the 2-cell stage to the morula is called:
Which of the following is incorrect regarding the notochord?
arises from a notochordal process which at first is a hollow tubular structure
is formed during gastrulation
arises from the primitive pit
divides the developing embryo into cephalic and caudal halves
lies along the long axis of the embryo
THe muscles of mastication arise from mesenchyme of the _________ branchial arch.
In the following list of events or stages, which of event would be third: Morula, Fertilization, Graffian follicle, Hatching, Implantation?
Which of the following is a false statement?
the zona pellucida is a matrix layer between the follicular epithelium and oocyte
a function of zona pellucida is to prevent premature implantation
zona pellucida encircles the morula
zona pellucida is surrounded by granulosa cells
zona pellucida is removed immediately following fertilization
Transport of the ovum is facilitated by:
the activity of cilia in the uterine tube
peristalic contractions of the muscularis of the uterine tube
the presence of active flagella in cells of the corona radiata
Meiosis is completed prior to ovulation.
The syncytiotrophoblast is derived from the outer cell mass while the cytotrophoblast is derived from cells of the inner cell mass.
Alveolar bone is formed from:
mesenchyme derived from somites
epithelium from the oral ectoderm
mesenchyme from the primitive streak
mesenchyme from notochord
The folding of the embryo causes:
endoderm to be on the inside of the embryo
ectoderm to be on the inside of endoderm
endoderm to be on the outside of the mesoderm
mesoderm to be on the outside of the ectoderm
From which embryonic layer is mesoderm derived?
in the ampulla of the oviduct
prior to blastocyst formation
during the morula stage
Which of the following statements concerning prenatal development is correct?
most congenital malformations occur during the last prenatal week
maturation of existing structures occurs during the second to eighth week
initiation of embryonic layers occurs during the first week
the fetus is the structure present during embryonic period
The oral plate consists of:
embryonic endoderm, mesoderm, ectoderm
a circular area anterior to the notochord in which the endoderm is fused to the embryonic mesoderm
the cloacal membrane and the overlying amnion
endoderm of the roof of the yolk sac and embryonic ectoderm
the cardiogenic mesoderm and the neuroectoderm
The first brachial arch gives rise to:
Somites form from:
Which of the following cells have migrated from the neuroectoderm and are the basis for future bone of the maxilla and mandible?
Embryologically the muscular wall of the gut arose from the:
parietal lateral plate mesoderm
visceral lateral plate mesoderm
The cells of the _______ will form the embryo proper.
inner cell mass
outer cell mass
At the beginning of the third week of development a thickening of ectoderm overlying the notochord indicates the start of:
primitive streak stage
Prior to the formation of the primitive streak the amnion and blastocystic cavity (yolk sac) communicate via the neuroenteric canal.
Regarding the early embryo, which of the following is False?
the epiblast faces the amniotic cavity
the embryonic shield consists of 2 layers prior to the formation of the primitive streak
following gastrulation mesoderm fills all the space between the ectoderm and endoderm
the hypoblast cells are primitive endoderm
Which of the following is Incorrect regarding the notochord?
it arises from a notochordal process which at first is a hollow tubular structure
it is formed during gastrulation
arises from the primitive node
it extends from the primitive pit in a caudal direction
divides the developing embryo into right and left halves
1. extraembryonic structures derived from the zygote
2. embryonic structures derived from the zygote
1, 2, & 3
1 & 3
Down syndrome is known for:
trisomy of chromosome number 20
production of a monosomy situation
facial enlargement and lengthened palate
fissured tongue and delayed tooth eruption
Which of the following supports the primitive embryo and is directly derived from ectoderm alone?
secondary yolk sac
Which of the following syndromes occurs due to failure of neural crest cells to migrate?
Fetal alcohol syndrome
Treacher Collins syndrome
The face develops in the human between:
6 and 10 days
10 and 22 days
12 and 22 days
24 and 38 days
Primitive oral cavity is called?
none of these
Proteins that bind to specific DNA sequences and regulate transfer of genetic information from DNA to mRNA are called: