Chapter 3 - Prenatal Development Flashcards
1
Q
Define embryology
A
study of prenatal development
2
Q
Duration of prenatal dev.
A
start of pregnancy - birth
3
Q
3 distinct successive periods are
A
preimplantation, embryonic period, and fetal
4
Q
The first trimester includes which 2 periods
A
preimplantation and embryonic
5
Q
The last two trimesters include which period
A
fetal
6
Q
what is primordium
A
earliest indication of a tissue type or an organ during prenatal development
7
Q
define congenital malformations
A
birth defects that are evident at birth
8
Q
which period and trimester do congenital malformations occur
A
first, implantation and embryonic
9
Q
How common are malformations
A
3/100
10
Q
What is the leading cause of infant death
A
congenital malformations
11
Q
define amniocentesis (amniotic fluid test), and how is it done
A
prenatal diagnostic procedure to detect chromosomal abnormalities. amniotic fluid is removed and the fetal cells are grown for study of the chromosomes and sampled for determination of other complications
12
Q
what cells are related to implantation period, and what occurs?
A
zygote turn into blastocyst. fertilization and implantation
13
Q
preimplantation period consists of which week/s?
A
first
14
Q
embryonic period consists of which week/s?
A
second - eighth
15
Q
which cells and structure are related to the embryonic period, and what happens?
A
disk > embryo > folded embryo. induction, proliferation, differentiation, morphogenesis, and maturation
16
Q
fetal period consists of which week/s?
A
third - ninth
17
Q
what forms during fetal period, and what happens?
A
embryo > fetus, maturation
18
Q
what causes malformation?
A
genetic factors (chromosome abnormalities), environmental agents and factors (infections, drugs, and radiation)
19
Q
what are considered to be teratogens
A
infections, drugs, and radiation
20
Q
zygote is
A
a fertilized egg
21
Q
how many chromosomes results in the final stages of meiosis
A
46
22
Q
XX chromosomes =
A
female
23
Q
XY chromosomes =
A
male
24
Q
What happens to the zygote after fertilization
A
mitosis
25
after initial cleavage during mitosis, what happens?
solid ball of cells from initial cleavage
26
a blastocyst forms from
a zygote that has fluid secreted by cells within the morula
27
what is mitosis
individual cell division
28
what is the difference between mitosis and meiosis
mitosis happens during tissue growth or regeneration, meiosis happens during fertilization
29
what happens during meiosis
ovum and sperm chromosomes join during fertilization
30
what is the self-duplication of the chromosomes of the parent cell and their equal distribution to daughter cells
mitosis
31
trophoblast layer is the
outside layer of the blastocyst
32
embryoblast layer is
the inner mass of embryonic cells in a blastocyst
33
What does the trophoblast layer do
gives rise to the embryo during the prenatal period
34
what chromosome is responsible for down syndrom
extra chromosome 21
35
define induction, and which period does it belong to
first process during embryonic period, one group of cells on another that leads to establishment of the developmental pathway in the responding tissue
36
what process follows induction, and what is it
proliferation during embryonic period, controls levels of cell growth present during prenatal dev.
37
what is appositional growth
tissue gets bigger by addition of layers on outside of structure
38
what happens during ectopic pregnancy
the zygote is implanted in the fallopian tube instead of uterus
39
what is interstitial growth
growth that's deep within tissue type or organ
40
is hard tissue growth appositional?
yes
41
Is soft tissue growth is what kind of growth
intersitial
42
which tissue types use both growth methods
cartilage and immature bone tissue
43
what is differentiation during growth
dividing cells change their functional or phenotypical type; different rate of growth for different internal tissue types and organs
44
cytodifferentiation is
dev. of diff. cell types
45
histodifferentiation
dev. of dif. histologic tissue types within structur
46
morphodifferentiation
dev. of differing morphology
47
what is morphology
structure or shape of each organ or system
48
what is morphogenesis
process of dev. of specific tissue stru. or shape
49
why does morphogenesis occur
it occurs due to the migration or proliferation of embryonic cells, which is follwed by the inductive interaction of those cells
50
maturation of tissue types and organs begin during which period
embryologic
51
what week does embryonic period end on, and what is recogniable
eighth, embryo
52
what is the germ layer, and where is it
embryonic cell layer within blastocyst
53
what is bilaminar embryonic disk
flattened 3D circular plate of bilayered cells consisting of superior epiblast and inferior hypoblast
54
what cells make up epiblast layer
high columnar cells
55
what cells make up the hypoblast layer
small cuboidal cells
56
what layer does the amniotic cavity face
epiblast
57
what layer does the yolk sac face
hypoblast
58
what serves as initial nourishment for the disk
yolk sac
59
what connects momma and embryo
endometrial tissue of placenta and trophoblast layer of blastocyte
60
what flows through the umbilical cord
selective exchange of soluble bloodborne substances, o2, co2, nutritional and hormonal substances
61
what is the primitive streak
forms inside bilaminar disc, is furrowed, rod shaped thickening in the middle of the disk
62
what does the primitive streak do to the bilaminar embryonic disk
causes disc to have bilateral symmetry, left and right half
63
what is mesoderm and what creates it
embryonic connective tissue, made of epiblast and hypoblast cells
64
what makes up the trilaminar embryonic disc
mesoderm, embryonic endoderm, and epiblast layer (ectoderm)
65
what tissue does ectoderm give rise to
skin epidermis, CNS, plus more
66
What tissues do the mesoderm give rise to
connective tissues (skin dermis), cartilage, bone, blood, muscle, and other associated tissue.
67
The endoderm gives rise to what?
the respiratory epithelium and cells of glands
68
cephalic end
head end
69
what membrane forms at the cephalic end, and what embryonic disc layer does it consist of?
oropharyngeal, ectoderm externally and endoderm internally. No mesoderm
70
where is the oropharyngeal membrane located and why is it significant
future primitive mouth (stomodeum) of the embryo, it's the start of the digestive tract
71
what is the caudal end
the tail end
72
what membrane form at caudal end, what what will grow there in the future
caudal membrane, anus/terminal end of the digestive tract
73
which layer of the embryonic disc creates the neuroectoderm, which is the start of the spinal cord and brain
ectoderm
74
where are neuroectoderm cells
neural plate of embryo
75
what are the stages of spine creation
neuroectoderm at neural plate, this extends length of embryo from cephalic to caudal end, with growth it will deepen and invaginate inward creating neural groove, the groove deepens and is surrounded by neural folds, more growth results a neural tube
76
what forms the future spinal chord
neural tube and other neural tissue of CNS
77
what creation developes face and neck structures
mesenchyme
78
what is the neural crest cells
deriving from neuroectoderm, they migrate from neural folds to join with mesoderm which forms mesenchyme. also considered as 4th embryonic cell layer
79
three major regions of the digestive tube
foregut (anterior), midgut, and hindgut (both posterior)
80
what period do all essential external and internal structures form, thus most critical
embryonic
81
ectodermal dysplasia is what and which period screws it up if disturbed
weird teeth, hair, skin, nails, eyes, face structure, and glands since they derive from ectoderm during embryonic period
82
anodontia
absence of some or all teeth in
83
somites are
when mesoderm differentiates and divides on each side of neural tube into 38 paired cuboidal segments of mesoderm
84
What is Treacher collins synd. (mandibulofacial dysostosis)
failure of ncc's migration to facial region. specific areas of orofacial development fails (downward slanting eyes), underdeveloped xzygomatic bone, drooping lateral lower eyelids, and conductive hearling loss, with malformed or absent ears, dental dev. disturbances (anodontia, enamel dysplasia, micrognathia (small lower jaw).
85
rubella is caused by, and can result in
cuased by teratogens, cataracts, heart defects, deafness
86
syphilis is caused by and can result in
teratogen, defects in the incisors and molars, blindness, deafness, and possibly paralysis
87
fetal alcohol syndrom
mental disabilities, small head circum., low nose bridge, short nose, small midface, wide spaced eyes, epicanthic folds and eyelid fissures, unclear philtrum, and thin upper lip. Also, oral changes, like croding, mouth breathing, open bite, and gum disease bc of finger sucking habit
88
what does radiation potentially do during prenatal growth
injure embryonic cells = cell death, chromosome injury, delay mental and physical growth
89
what is spina bifida
failure of fusion of the neural tube defects the vertebral arches and various degrees of disability.
90
which period do embryo's begin breathing
third week of prenat. dev.
91
which period do fetases heart beat and move
end of fourth month
