Intro to Embryology Flashcards
1
Q
duration of full term development for baby
A
- 38 weeks
2
Q
duration of full term development for mom
A
- 40 weeks from LMP
3
Q
name for weeks 1-2 of development
A
- no name
4
Q
conceptus name for weeks 1-2 of development
A
- zygote
- morula
- blastocyst
5
Q
major events for weeks 1-2 of development
A
- fertilization
- implantation
6
Q
name for weeks 3-8 of development
A
- embryonic peroid
7
Q
conceptus name for weeks 3-8 of development
A
- embryo
8
Q
major events during weeks 3-8 of development
A
- organogenesis
9
Q
name for weeks 9-38 of development
A
- fetal period
10
Q
conceptus name for weeks 9-38 of development
A
- fetus
11
Q
major events during weeks 9-38 of development
A
- growth
- maturation
12
Q
development occurs at what level?
A
- cellular level
13
Q
development starts with?
A
- pluripotential cells
14
Q
how does development occur?
A
- in a series of time-locked steps in which a cell differentiates and matures
15
Q
each step of development
A
- is induced by a message from a neighboring cell
16
Q
each step only occurs if
A
- cell 2 has the receptors to perceive the inductive message
17
Q
what happens during induction
A
- cell 2 becomes more differentiated
18
Q
the group of cells which influence the responding cells are termed
A
- inducing tissue
19
Q
teratogen definition
A
- any agent or factor that causes the body parts to develop abnormally
20
Q
many teratogens will arrive via
A
- the mother’s blood
21
Q
categories of teratogens
A
- medications
- substances of abuse
- chemicals
- microbes
- radiation
22
Q
the study of abnormal development
A
- teratology
23
Q
an abnormality present at birth
A
- birth defect
- congenital abnormality
- congenital anomaly
24
Q
the developmental structural abnormality arising in the embryonic period (weeks 3-8)
A
- malformation
25
developmental structural abnormality secondary to extrinsic disruption after embryonic period (weeks 3-8)
- deformation
26
multiple abnormalities all developing in a sequence
- sequence
27
multiple abnormalities developing in no known sequence
- syndrome
28
normal development in pre-fertilization
- meiosis produces egg and sperm
29
abnormal development in pre-fertilization
- genetic abnormalities
30
example of an abnormal development in pre-fertilization
- downs syndrome
31
normal development in weeks 1,2
- mitosis
- move to uterus
- begin implantation in uterine wall
32
abnormal development in weeks 1,2
- not susceptible to teratogens
- secondary to inherited genetic abnormalities
- 40-50% spontaneously abort
33
normal development in weeks 3-8
- form organs
34
abnormal development in weeks 3-8
- susceptible to all types of birth defect etiologies
| - most vulnerable time for embryo
35
major abnormal development during weeks 3-8 occurs because
- structure is only made of a few cells
| - abnormal cells build abnormal organ
36
normal development in fetal period
- growth and maturation
37
abnormal development in fetal period
- susceptible to all types of birth defect etiologies
38
why do minor anomalies develop in the fetal period
- development of a structure is disrupted when it is nearly fully formed
39
another name for cranial
- rostral
40
the head view is called
- cranial
| - rostral
41
the tail view is called
- caudal
42
directions of development
- proximal -> distal
| - cranial -> caudal
43
what forms the placenta
- the embryo
44
what does maternal blood release into the placenta to go into fetal blood
- nutrients
| - O2
45
what does the fetus release into the placenta to go into maternal blood
- wastes
46
is there mixing of fetal and maternal blood
- no
47
what does the fetus breathe
- amniotic fluid
48
does the fetus urinate into the amniotic fluid?
- yes
49
does the fetus defecate in-utero?
- no
50
what does the placenta function as
- fetal lungs
- kidneys
- GI tract
51
process of week 1 development
- fertilization
- cell division
- zygote -> morula -> blastocyst
- implantation in uterus
52
what does the inner cell mass eventually become?
- fetus
53
what does the trophoblast eventually become?
- placenta
| - fetal membranes
54
inner cell mass in week two development
- two layers
55
the two layers of the inner cell mass in week two development
- epiblast
| - hypoblast
56
what happens to the epiblast
- becomes the embryo
57
what happens to the hypoblast
- disappears
58
what appears in week 2 of development
- amniotic cavity
| - primitive streak
59
where does the primitive streak form
- epiblast
| - dorsal, caudal midline
60
what occurs in week 3 of development
- gastrulation
- trilaminar embryo
- somite formation
- neurulation
61
what occurs in gastrulation
- formation of the 3 germ layers from the primitive streak
62
what 3 germ layers are formed from the primitive streak?
- ectoderm
- mesoderm
- endoderm
63
what is the trilaminar embryo formed from?
- the 3 germ layers
64
somite formation
- formation of the horizontal body segments
65
neurulation
- formation of the nervous system
66
what happens to the epiblast at week 3
- mitosis of epiblast at primitive streak
- forms new cells
- migrate under epiblast layer
- form mesoderm and endoderm
- epiblast renamed ectoderm
67
ectoderm gives rise to
- outer layer of skin (epidermis) and teeth (enamel)
| - nervous system
68
mesoderm gives rise to
- muscle
- bone
- connective tissues
- blood and blood vessels
- deeper layer of skin (dermis)
69
endoderm gives rise to
- epithelial lining of GI and respiratory tracts
70
mesenchyme are aggregation of
- undifferentiated cells
71
mesenchyme mostly comes from
- mesoderm
72
somite definition
- horizontal body segments composed of skin, muscle, bone, connective tissue
73
somites form from
how many pairs?
- paraxial mesoderm
- paired thickenings
- 35-37 pairs
74
each somite divides into
- dermatome
- myotome
- sclerotome
75
dermatome becomes
- skin dermis
76
myotome becomes
- muscle
77
sclerotome becomes
- bone
78
week 4 development
- organogenesis
- folding
- germ layer differentiation
- pharyngeal arches
- heart forms and begins beating
- 4 limbs begin developing
79
what type of folding occurs in week 4
- longitudinal
| - transverse
80
how does the embryo begin week 4?
- flat
81
what does folding create
- 3D trunk
82
what does longitudinal folding do?
- moves the heart from the cranial into the newly formed thorax
83
how do cranial and caudal ends fold in longitudinal folding?
- fold ventrally
84
process of longitudinal folding?
- flat -> C shaped
85
how does transverse folding occur?
- lateral sides fold ventrally until they meet and fuse in ventral/anterior midline
86
what does transverse folding create?
- the GI tract
- body cavities (coelom)
- germ layer differentiation
87
organ structures at the beginning of week 5
- mostly present but rudimentary
88
organ structures by the end of week 8
- fairly mature
