Embryo Test 1 Flashcards
(133 cards)
1
Q
Decidual reaction
A
Endometrium cells SWELL as they will with glycogen and lipids,
Provide nutrients to embryo
2
Q
Capacitation rxn
A
Sperm undergo a 7 hr period of maturation within ISTHMUS of uterine tube
3
Q
Zona rxn
A
Sperm make oocyte impermeable so other spermies cannot get in
4
Q
Acrosome rxn
A
Sperm release enzymes thru acrosome to penetrate thru corona radiata
5
Q
Physical function of hCG
A
Maintains corpus luteum of pregnancy
6
Q
Clinical function of hCG
A
Positive pregnancy test. Tells u implantation has occurred
7
Q
Bilaminar disc layers
A
Epi/ hypo blast
8
Q
What separates the epiblast from the amnion
A
Amnioblast
9
Q
Day 13/ 14 are characterized by:
A
Development of chorionic villi (site of gas and nutrient exchange within the placenta)
10
Q
What does the extraembryonic coelom divide the extraembryonic mesoderm into
A
Extraembryonic somatic mesoderm
Extraembryonic splanchnic mesoderm
11
Q
What does the extraembryonic somatic mesoderm give rise to
A
Lining of cytotrophoblast and amnion
12
Q
What does the extraembryonic splanchinc mesoderm give rise to
A
Lining umbilical vesicle
13
Q
Chorion is formed by :
A
Extraembryonic somatic mesoderm
Cytotrophoblast
Synctytiotrophoblast
14
Q
Suspended within the chorionic sac by the connecting stalk are the:
A
Embryo
Amniotic sac
Umbilical vesicle
15
Q
What divides the chorionic cavity
A
Extraembryonic coelom
16
Q
Day 14- the ____ cells in one area of Bilaminar disc elongate to form _____
A
Hypoblast, prechordal plate
17
Q
What does the prechordal plate form
A
Mouth, but important for development of head
18
Q
Where do BV’s first appear
A
Connecting stalk,
Chorion,
Umbilical vesicle
19
Q
What is the name for the hamburger drawing / what does it consist of
A
“Conceptus” (embryo + assoc. membranes)
Top bun=amniotic sac
Buns = bilaminar disc
Bottom bun= umbilical vesicle
All in chorionic sac
Chorion surrounds
CONNECTING STALK connects hamburger to chorionic sac
20
Q
What is an ectopic pregnancy
A
Abnormal implantation anywhere outside the uterine cavity
21
Q
Types of ectopic pregnancies discussed in class (and the most common)
A
1.) ectopic tubal pregnancy (MOST COMMON)
2.) ectopic abdominal pregnancy
3.) ectopic cervical pregnancy
4.) ectopic mesenteric pregnancy
5.) primary ovarian pregnancy
22
Q
What is ectopic tubal pregnancy
A
Implantation occurs in uterine tube
23
Q
What is ectopic abdominal pregnancy
A
Implantation in rectouterine pouch
24
Q
What is ectopic cervical pregnancy
A
Implantation in cervical canal
25
What is ectopic mesenteric pregnancy
Implantation in mesentery of small intestine
26
What is primary ovarian pregnancy
Implantation in ovary
27
What is a spontaneous abortion
Aka miscarriage, occurs within the first 3 weeks after fertilization
28
What causes most spontaneous abortions
Chromosomal abnormalities
29
When is spontaneous abortion most likely? Teratogenesis?
Spontaneous abortion- within the first 3 weeks
Teratogenesis- week 3-8, high spike at week 5
30
What is special about week 3 of development
Trilaminar disc aka 3 germ layers
31
1st event of week 3
Gastrulation
32
What is gastrulation
Bi to tri laminar disc
33
What does the bi to tri laminar disc (gastrulation ) begin with
Primitive streak in epiblast
34
What is a key process during gastrulation
Morphogenesis: the development of the body starts to form
35
Describe the process of the primitive streak in gastrulation
Cells of epiblast migrate toward primitive streak and move inward beneath it (invagination)
36
Which germ layer(s) replace the hypoblast
Endoderm
37
What layer of bilamiar disc is source of all germ layers
The epiblast
38
What color represents endoderm
Yellow
39
Color that represents mesoderm
Red
40
Color that represents ectoderm
Blue
41
When does primitive streak disappear
By the end of the 4th week
42
What is the 2nd major event of week 3
Notochord formation
43
The notochord process consists of what germ layer
Mesoderm
44
When direction does the notochord grow
Cranially
45
What represents the future site of the oral cavity
Oropharyngeal membrane
46
What represents the future site of the Anus
Cloacal membrane
47
Cranial and caudal end of primitive streak:
Cranial: prechordal plate
Caudal:cloacal membrane
48
By the middle of the 3rd week, mesoderm separates endoderm/ectoderm everywhere except..
Opopharyngeal membrane (cranial)
Cloacal membrane (caudal)
** ECTO/ENDODERM =. FUSED, preventing entrance of mesoderm ****
49
Where does the notochord come from
Notochordal plate
50
Importance of the notochord:
1.) defines the longitudinal axis of the embryo
2.) provides rigidity to the embryo
3.) forms the central part of the intervertebral discs (nucleus pulposus.. gel-like)
4.)signaling center for development in early embryo
51
T/F the notochord degenerates as the vertebral bodies grow
True, only thing left is the nucleus pulposus
52
What is the third major process in week 3
Neurulation
53
What is neurulation
Formation of neural tube
54
The neural tube gives rise to what nervous system
CNS
55
Notochord + ectoderm =
Neural plate
56
Neural plate —>
Invaginates to form neural groove
57
What happens when neural folds approach each other
Neural tube
58
What is the 4th major event of week 3
Neural crest development
59
After they develop, Neural crest cells __
Separates into 2
60
Neural crest cells take on characteristics of the
Mesenchyme
61
Mesenchyme:
Undifferentiated CT
62
Where do the neural crest halves go
Alongside dorsolateral aspect of neural tube
63
“4th germ layer”
Neural crest ..
Many PNS /mesenchymal structures of head and neck are derived from neural crest cells
64
What is the 5th major event in week 3
Somite formation
65
Which germ layer is organized into 3 columns during somite formation process
Mesoderm
66
What are the 3 layers of the mesoderm during somite formation
1- paraxial mesoderm (adjacent to notochord)
2- intermediate mesoderm
3-lateral mesoderm (continuous with extraembryonic mesoderm of umbilical vesicle and amnion
67
Paraxial mesoderm does what at end of week 3
Differentiates and divides into somites
68
Where can somites be found
Either side or notochord and developing neural tube
69
By week 5, there are how many pairs of somites
42 to 44
70
Where does somite development begin/ what way does it move
Occipital region of head, moves caudally
71
Somites give rise to..
-axial skeleton (ex: vertebrae column)
-axial musculature
-dermis of skin (CT of skin, deeper layer)
72
What is the first fully functioning system in an embryo
Cardiovascular system
73
During 2nd week of development, embryo receives oxygen and nutrients from mother via diffusion from the :
-Extraembryoic coelom
-umbilical vesicle
74
By week 3, BV’s appear in :
-umbilical vesicle
-connecting stalk
-chorion
75
When does heart begin formation
By end of 3rd week
76
When does heart beat/ blood circulate
Week 4
77
What is the last major event of week 3
Chorionic villi
78
Primary chorionic villi:
Appear during week 2 as cell extensions which grow into synchtiotrophoblasts
79
Secondary chorionic villi
Developer early in week 3, when mesenchyme grows into the primary villi
80
Tertiary chorionic villi
Develop near end of week 3, when capillaries grow into the villi. (Capillaries become connected to the embryonic heart thru BV growth)
* important because all nutrients, oxygen, etc. reach the embryo here*
81
By end of week 3, ___ and ___ is entering embryo, while __ and ___ are excreted into maternal blood via chorionic villi
Oxygen, nutrients, Carbon dioxide, waste products
82
What forms the cytotrophoblastic shell?
Cytotrophoblastic process from chorionic villi
83
What does the cytotrophoblastic shell/ sac anchor on to
Endometrium
84
What is the hydatidiform mole
Embryo dies, chorionic villi degenerate/ form cysts which look like grapes
85
When is the hydatidiform mole most common
Fertilization of an oocyte lacking a female pronucleus, “monospermic”
86
Week 4-8 of embryonic development is important because..
All major external features and organ systems have begun their development
87
Trilaminar disc changes to a…
“Distinctly human form”
88
Major thing to remember with week 4..
Embryonic folding
89
Ventral folding of embryo occurs at the :
Cranial end
Caudal end
Lateral edges
90
____ Folding of the head becomes the ____
Ventral, Foregut
91
Ventral cranial folding causes what organ to move ventrally
Heart
92
___ folding of the ___ end forms HIND GUT
Ventral, caudal
93
Ventral folding of LATERAL EDGES of the embryo forms ____
MID GUT
94
Cranial end= __ gut
Fore
95
Caudal end = __ gut
Hind
96
What happens in Week 6:
Spontaneous movements of the embryo (twitching)
97
When should a heartbeat be detectable
6-7 weeks
98
During week 8, what happens
The first PURPOSEFUL movements of the limbs
99
T/F all tissues and organs are derived from 3 germ layers
True
100
What does ectoderm give rise to
2 divisions: surface ectoderm and neuroectoderm (2 parts)
101
The surface ectoderm gives rise to what organs/tissues
-Epidermis and derivatives (hair, nails, cutaneous/ mammary glands)
-dental enamel
-special sense organs (eyes, ears)
-ANT PITUITARY GLAND
102
The 2 parts of the neuroectoderm
-neural tube
-neural crest cells
103
What does the neural tube give rise to
-CNS
-POST pituitary gland
-PINEAL gland
-retina
104
What do neural crest cells give rise to
-spinal root ganglia
-autonomic ganglia
-neurolemma of peripheral nerves
-arachnoid and pia mater
-medulla of suprarenal gland
-melanocytes
-HEAD AND NECK structures derived form mesenchyme
-outflow tract of heart
105
Mesoderm gives rise to what divisions
Paraxial mesoderm
Intermediate mesoderm
Lateral mesoderm
106
What does the paraxial mesoderm give rise to
(Forms somites)
Bone
CT
Muscle
Dermis
107
Intermediate mesoderm gives rise to
-organs and ducts of urinary system
-organs and ducts of reproductive systems
108
The lateral mesoderm gives rise to
-cardiovascular system (blood cells)
-lymphatic system
-STROMA OF ORGANs (acts as CT for organs) (gives organ shape)
-membranes lining body cavities
-cortex of suprarenal gland
109
STROMA vs parenchyma
STROMA is the ct framework of an organ
Parenchyma is the functional cells of an organ
110
The endoderm gives rise to
-epithelium of respiratory system
-epithelium of digestive system
-epithelium of bladder/ urethra
-parenchyma of liver, pancreas, thyroid, parathyroid, tonsils, and thymus
111
The process of embryonic development occurs in how many phases?
3
112
Embryonic development is controlled by what
Interaction of genetic and environmental factors
113
What are the 3 phases of embryonic development
-growth (cell div)
-morphogenesis (development of organs)
-differentiation (production of specialized cell types and their organization into functional tissues and organs)
114
Factors involved in embryonic development:
1.) tissue interactions
2.) regulated migration of cells
3.) regulated proliferation of cells
4.) apoptosis
115
What is induction
The interaction between tissues which leads to a change in the course of development
116
What changes the course of development of the reacting tissue
The inductor tissue
117
Induction happens bc of tissue signaling. What are the 3 forms of signaling
1.) diffusible molecule (ex: sonic hedgehog)
2.) nondiffusible matrix secreted by the inductor
3.) direct physical contact between the inductor and responding tissue
118
How long are reacting tissues receptive to induction
Only for a limited time,
119
Failure of induction to occur during the limited time it has results in what
Developmental errors
‘Key will only lock for a certain amount of time”
120
How long is the normal pregnancy
40 weeks (from the first day of the last normal menstrual period)
121
How long is normal pregnancy after fertilization
38 weeks, (two weeks after last normal menstrual period)
122
How is gestational age dates
From the last normal menstrual period (LNMP)
123
How is the embryonic age dated
From fertilization
124
Factors which affect the reliability of using the LNMP to estimate age of embryo:
-oligomenorrhea (scantly menstrual flow)
-cessation of oral contraceptive use
-use of IUD
-postpartum pregnancy (short interval between pregnancies)
125
When is the fetal period
From week 9- birth
126
What is the fetal period characterized by
Rapid body growth / maturation of the tissues and body systems established during embryonic period
127
Does the head grow fast or slow in the fetal period
Slow (compared to rest of body)
128
Is fetus more or less susceptible to terratogenic agents than the embryo
Less
129
How are fetal measurements measured
Via ultrasound
130
How is length of fetus described
-crown- rump length (CRL): sitting height
-crown-heel length (CHL): standing height (vertex to heel)
131
What does measurement of the head include
-biparietal diameter (measured bt 2 parietal eminences)
-head circumference
*measurements are estimates using ultrasonography / fetus age to assess growth rate *
132
When is growth in length particularly pronounced
Months 3-5
133
When is increase in weight most rapid
Months 8-9
