Exam 2 Flashcards
1
Q
what is the name of the process by which the bilaminar germ disc is converted to a trilaminar germ disc?
A
Gastrulation
2
Q
what is Gastrulation?
A
the process by which a bilaminar germ disc is converted into a trilaminar disc
3
Q
what is the beginning of Morphogenesis?
A
Gastrulation is the beginning of morphogenesis
4
Q
the Embryo can be referred to as?
A
the Gastrula
5
Q
Rapid development of the embryo from the trilaminar embryonic disc during the third week is characterized by?
A
- the appearance of the primitive streak
- Development of the Notochord
- Differentiation of the three germ layers
6
Q
what are the genes that play a role in gastrulation?
A
- Bone morphogenetic proteins
- SHH- sonic hedgehog
- Tgifs
- Wnts
7
Q
what are the three layers of the Gastrula from top to bottom?
A
- Embryonic Ectoderm- Top layer
- Embryonic Endoderm- Middle Layer
- Embryonic Mesoderm- Bottom layer
8
Q
Embryonic Ectoderm gives rise to what parts of the body?
A
- Epidermis
- Central and peripheral nervous systems
- Eyes
- Internal Ears
- and as neural crest cells, develops many connective tissues of the head.
9
Q
The Embryonic Endoderm is the source of what parts of the body?
A
- epithelial linings of the respiratory and alimentary (digestive) tracts
- the glands opening into the gastrointestinal tract
- the glandular cells of associated organs, such as the liver and pancreas
10
Q
The Embryonic Mesoderm gives rise to the most body parts, what are they?
A
- skeletal muscles
- blood cells and the lining of blood vessels
- all visceral smooth muscular coats
- serosal linings of all body cavities
- ducts and organs of the reproductive and excretory systems
- most of the cardiovascular systems
11
Q
the parts of the trunk formed by the Embryonic Mesoderm?
A
all connective tissue, including cartilage, bones, tendons, ligaments, dermis, and stroma (connective tissue) of internal organs
12
Q
the thick band of epiblast cells that converge caudally in the midline of the disc on/around the 15th day?
A
the primitive streak, which has a caudal and cranial end.
13
Q
what is the thickened round area at the cranial end of the bilaminar disc?
A
Primitive Node
14
Q
The narrow grrove that runs down the primitive streak?
A
Primitive Groove
15
Q
At the end of the Primitive Groove in the Primitive node is the?
A
Primitive Pit
16
Q
the appearance of the primitive streak divides the embryo into what directions/part?
A
- Cranial part
- Caudal part
17
Q
Epiblast cells migrate through the primitive streak, moving into the layer between the ________ and ________.
A
epiblast and hypoblast
this displaces the hypoblast
18
Q
during the migration of epiblast cells, the cells from the deep epiblast area form?
A
mesenchyme
19
Q
part of the mesenchyme becomes which embryonic layer?
A
the middle layer
Embryonic Mesoderm
20
Q
the epiblast cells displaced the hypoblasts to form what layer?
A
the endoderm
21
Q
the ectoderm is formed from the remaining _______ cells?
A
remaining epiblast cells
22
Q
what is a Sacrococcygeal Teratoma?
A
- remaining remnants of the primitive streak
- Gives rise to a tumor
- most common tumor in newborns
- pluripotent cells
23
Q
on the 22-24 day the notochord detahes from the endoderm and retreats into the?
A
mesoderm
this process changes the notochord into a chord with a canal
24
Q
the Body Mesoderm extends over all of the germ dics except in what two areas?
A
Porchordal (prechordal) plate- cranial end
Cloacal Plate-Caudal plate
25
the Cloacal plate is at the caudal end of the embryo and forms the?
primitive anus
26
the cloacal membrane/plate disintegrates in the 7th week to form the openings of the?
anus
urinary
genital tracts
27
the functions of the notochord?
- support of growing embryo
- induction of a neural plate
- disappears when vertebrae forms
- small portion persists- nucleus pulposus
28
what is vasculogensis?
formation of vascular channels
29
what is angiogenesis?
formation of vessels
30
what genes regulate intrauterine growth?
H19
IGF2
IGF2r
MASH2
31
methylation of DNA plays a role in the __________ and ___________ of endogenous genes?
imprinting and expression
32
which genes regulate the cells of the epiblast to cause involution into the primitive streak and placement between the epiblast and the hypoblast layer.
zygotic genes
33
the organizer of the embryo?
primitive node
34
factors such as B-catenin and members of the transforming growth factor, from the maternal effect genes induce the epiblast to form the?
primitive streak
35
what defines the left and right side of the embryo?
the primitive streak
36
which genes play a role in development of handed asymmetry?
nodal genes
37
cell lineage studies have shown epiblast cells to be?
pluripotent
38
pluripotent can develop into?
almost any cell type of the embryo
39
what is the support system of the developing embryo?
Notochord
40
what is the primary inducer of the overlying ectoderm to form the neural plate?
The Notochord
41
the notochord is the primordial axis of the embryo around which the _______ _________ forms
axial skeleton
42
the process of conversion of the neural plate from a neural tube happens in what week?
the fourth week
43
the process of converting the neural plate to the neural tube starts with folding, which is called?
neurulation, it creases ventrally along its mid-line and develops a neural groove.
44
when the neural folds curl and become concave and the edges of the folds meet and fuse. this forms?
a neural canal
45
the edges of the neural folds make contact on the ___ day of development?
22nd day
46
the newly formed neural canal communicates with the amniotic cavity through large opening called?
cranial and caudal neurophores
| these neurophores close by the 26th day
47
the neural tube differentiates into?
brain and spinal cord
48
neural crest cells differentiate into?
sensory ganglia
medulla of the adrenal glands
pigment cells of the body
49
the ganglia of what cranial nerves are partly derived from the neural crest cells?
V, VII, IX, X
| it also forms the neurolemma sheaths of the peripheral nerves
50
interruption of the neural tube closure is the underlying cause of?
spinal bifida and anencephaly
51
abnormalities of the neural tube closure affect the development of?
nervous system
vertebral arch
cranial vault
52
on each side of the notochord, thickened areas become the?
paraaxial mesoderm
53
the lateral area on each side of a notochord becomes the?
lateral mesoderm
54
the mesoderm layer between two areas of mesoderm?
intermediate mesoderm
55
the main ectoderm layer gives rise to?
```
central nervous system
peripheral nervous system
sensory epithelia of the ears,eyes, and nose
epidermis and appendages (hair and nails)
mammary glands
pituitary glands
subcutaneous glands
enamel of teeth
```
56
the main mesoderm layer gives rise to?
```
connective tissue
cartilage
bone
striated and smooth muscles
heart,blood, and lymphatic vessels
kidneys
ovaries, testes, genital ducts
serous membrane lining the body cavities
spleen and cortex of the suprarenal glands
```
57
the main endoderm layer gives rise to?
- epithelial lining of the digestive and respiratory tracts
- parenchyma of the tonsils
- thyroid and parathyroid glands, thymus, liver and pancreas, epithelial lining of the urinary bladder and most of the urethra
- epithelial lining of the tympanic antrum and pharyngotympanic tube
58
the paraxial mesoderm breaks up into bea dshaped blocks called?
somites
42-44 pairs are formed
they are loacted on the sides of the neural tube
59
the 42-44 somites are distributed into what six groups and distributed how?
- occipital 4 pairs
- cervical 8 pairs
- thoracic 12 pairs
- lumbar 5 pairs
- sacral 5 pairs
- coccygeal 8-10 pairs
60
what are somites?
segemented mesodermal tissue along the neural tube, which gives rise to vertebral column, voluntary muscle, connective tissue, skin.
61
when the cells of each germ layer divides, the migrate and differentiate to form various organ systems. this is known as?
organogenesis
62
ectodermal derivatives include?
```
central nervous system
peripheral nervous system
autonomic nervous system
sensory epithelium
epidermis and derivities
pituitary
```
63
the ectorderm breaks into two sections called the?
body ectoderm and neuroectoderm
64
the neuroectoderm breaks into two sections called the?
neural crest cells and the neural tube
65
the neural tube gives rise to?
brain and spinal cord
| cns and pns
66
the neural crest cells become the?
sensory ganglia
medulla of adrenal gland
pigment cells of the body
neurilemma of the PNS
67
the mesoderm breaks into what two sections?
Body mesoderm
| Chorda Mesoderrm
68
the Chorda mesoderm becomes the?
Notochord
69
the Body mesoderm breaks into what three sections?
paraxial
intermediate
lateral
70
the paraxial becomes the?
somites (21st day- 5th week)
71
the intermediate mesoderm becomes the?
urinary system (7th- 28th week)
72
the lateral mesoderm becomes the?
splanchnic and somatic
73
the splanchnic gives rise to the?
```
blood and blood vessels
heart
lymphatic
cardiac and visceral muscles
adrenal cortex
```
74
the somatic gives rise to the?
skull and muscles of the head
75
the intermediate mesoderm differentiates in two ways?
segemental in the cervical and thoracic regions
| caudally remians non-segmental
76
the urogenital system (gonads, ducts, glands) is formed by which part of the mesoderm?
lateral mesoderm
77
the lateral mesoderm is an extensive sheet of mesoderm with two layers separated by a space. what is the space called?
Coelom
78
the somatic layer of the lateral mesoderm is located next to which Main layer of the disc?
Ectoderm
79
the splanchnic layer of the lateral mesoderm is located next to what main layer of the disc?
Endoderm
80
some derivatives of the lateral mesoderm?
blood and blood vessels
heart and lymph vessels
cardiac and visceral muscles
adrenal cortex
81
some derivatives of the endoderm layer?
respiratory system
| digestive system
82
some derivatives of the endoderm?
epithelia of digestive tract
respiratory tract
liver and pancreas
thyroid and parathyroid
83
the surface ectoderm gives rise to?
```
epidermis
hair
nails
mammary glands
lens
anterior pituitary
```
84
the somites give rise to?
myotome
sclerotome
dermatome
85
noticeable changes in the fifth week of development?
enlargement of the head
brain growth
facial growth
86
noticeable changes in the eighth week of development?
```
digits of hands separate
all regions of limbs are apparent
limb movements
large head region
distinctive human characteristics
caudal eminence disappears
```
87
what is perinatology?
the study of the fetus and newborn as patient.
| from 22 weeks after fertilization to 4 weeks after birth
88
study concerned with the fetus is called?
fetology
89
the sampling of amniotic fluid by inserting a hollow needle into mother's abdominal and uterine wall is called?
amniocentesis
90
how much fluid is withdrawn during amniocentesis and what is its purpose?
15-30 milliliters is withdrawn and its purpose is to detect abnormalities
91
some indications that an amniocentesis should be performed?
late maternal age (38 years and up)
previous births with chromosomal abnormalities
carrier of an inborn metabolic disorder
family history of defects related to development
92
accurate measurements of the biparietal diameter of the fetal skull is done with what? and what does it determine?
ultrasound and it determines fetal age
93
the first of the three ultrasounds during a normal pregnancy occurs when and what does it tell?
7-8th week
confirms pregnancy
look for ectopic
94
the second of the three ultrasounds occurs when and tells what?
18-20th weeks
look for congenital malformations
multiple pregnancy
position of placenta
95
the third of the three ultrasounds occurs when and tells what?
34th week
fetal size
growth
position
96
when is the crown rump length measured with ultrasound?
7-8 weeks
97
when is the fetal length measured with ultrasound?
13-14 weeks
98
when is the biparietal diameter of the skull measured with ultrasound?
13-14 weeks
99
when fiberoptics are used to scan the entire fetus, by injecting a radiopaque substance to outline the fetus in the amniotic cavity?
fetoscopy
| the substance is absorbed by the vernix caseosa
100
the risks of fetoscopy?
higher risk factors
5-6% of fetal death and spontaneous abortions
radiation-exposure thyroid abnormalities
101
when a biopsy of the chorionic villi (mosty trophoblast) may be obtained by inserting a needle into the abdominal and uterine wall, it is called?
chorionic villus sampling (CVS)
102
the advantages of CVS?
it allows the results of chromosomal analysis weeks earlier than amniocentesis
103
location and characteristics of fetal sex cells?
sex chromatin in the nucleus of the cell
retrieved from amniotic fluid
found in normal female cells
buccal smear
104
what is the glycoprotein synthesized in the fetal liver, yolk sac and gut, that peaks around the 14th week?
Alpha Fetoprotein
105
increased AFP and fetal anomalies, sign and symptoms?
```
higher in multiple gestation
fetal death
neural tube defects
fetal bleeding
turners syndrome
```
106
Decreased AFP can determine?
maternal serum is low when fetus has Trisomy 21 and is coupled with increase in HCG
107
at 20 weeks, fetal blood samples are obtained from the umbilical vessels to diagnose?
severe fetal anomalies (Trisomy 13)
108
the maternal uterine tissue and lacunae helping in the formation of the placenta, also the base where the placenta is attached?
Decidua Basalis
109
The villi associated with the decidua Basalis grow rapidly and branch to become?
Cotyledon
110
the Cotyledon attaches to decidua Basalis and lacunae which becomes filled with?
maternal blood
111
the uterine endometrium covering the blastocyst at the aembryonic end?
Decidua Capularis
112
the Uterine endometrium opposite to the sides of implantation?
Decidua Parietalis
113
the amniotic sac (cavity) grows faster than smooth chorionic membrane and they fuse to form?
amniochorionic membrane
| this is the membrane that ruptures during labor
114
weight and characteristics of the placenta?
weights one seventh the weight of the fetus
Discoid shape
15-20 cm - 3 cm thick
115
maternal blood enters into the decidua basalis by the?
spiral endometrial arteries
| drained by the endometrial veins
116
in fetal circulation deoxygenated blood is brought to the placenta by the?
umbilical arteries
these arteries form an Arterio-Capillary-Venous network in the villi.
the lungs are bypassed
117
small amounts of fetal blood may pass into maternal blood via small tears in the placenta?
hemolytic disease
118
oxygenated blood passes into fetus through the?
umbilical vein
119
the rate of flow in the placenta is relatively?
high
120
the integrity of the fetal development is dependent upon the adequate bathing of the villi by the ?
maternal blood
121
decrease in oxygen due to acute reduction in the maternal blood flow?
fetal hypoxia
can cause death
maternal smoking can cause this
122
the four layers of the placenta membrane?
synthrophoblast
cytotrophoblast
connective tissue layer
endothelium of fetal capillaries
123
the three functions of the placenta?
metabolic
transfer
synthesis
124
describe the metabolic function of the placenta?
involved in the synthesis of
glycogen
cholesterol
source of energy and nutrient for the fetus
125
materials are transported across the placental membranes by four methods?
simple diffusion
facilitated diffusion
active transport
pinocytosis
126
what is simple diffusion?
movement of molecules by their own energy during diffusion
127
what is facilitated diffusion?
diffusion across a cell membrane in which the molecules to be transported form complexes with specific carriers
128
what is active transport?
plasma membrane moves molecules against diffusion pressure
| energy is needed
129
what is pinocytosis?
the passage of large molecules through the plasma membrane.
130
the formation of fluid filled vacuoles at the surface of the cell?
pinocytosis
131
Amniotic Fluid Functions?
```
Fetal movement
proportionate growth
prevents adherence
cushions the fetus
supplies nutrients
consistent body temp
helps lubricate and dilate the cervix during birth
```
132
abnormal amniotic fluid
oligohydramnios -400 ml or less
133
causes of abnormal amniotic fluid?
amniotic fluid leakage
bilateral renal agenesis
polycycstic kidneys
urethral obstruction
134
2000 ml or more of amniotic fluid
polyhydraminos
135
causes of polyhydraminos?
esophageal or intestinal atresia
| esophageotracheal fistula
136
Umbilical Cord characteristics
1-2cm diameter
| 50-60 cm length
137
the contents of the umbilical cord?
one vein, two arteries
138
blood vessels form in the wall of the yolk sac and allantois during the __ and ___ week.
3rd and 5th
| both disappear by 3.5 months of development
139
the yolk sac is known as?
the primary umbilical vesicle
140
primordial germ cells develop in ____ ____ and migrate to genital ridges in embryo.
becomes the vitelline vessels
yolk sac
141
what vessels become part of the umbilical vessels?
alantois
142
what becomes the median umbilical ligament in adults?
alantois
143
Urachus means?
fetus
144
the intraembryonic coelom forms what 3 major cavities?
pericardial
pleural
peritoneal
145
the body cavity is partitioned inferiorly by the?
diaphragm
146
the body cavity is superiorly partitioned by the?
pleuropericardial fold between the heart and lungs
147
each somite divides into what two parts?
Dermomyotome
-dermatome
-myotome
Sclerotome
148
from the ventromedial part of the somite, the development of the skeleton forms. this is known as ?
the Sclerotome
149
mesodermal cells give rise to?
mesenchyme
150
what is mesenchyme?
a meshwork of loosely organized embryonic connective tissue
151
condensation of mesenchyme will give rise to the formation of?
bone models
152
the mesenchyme develops from three other areas?
somite mesoderm
lateral mesoderm
paraxial mesoderm
153
cartilage is derived from?
mesenchyme
154
areas where cartilage is to form, mesenchyme condenses and forms?
chondrification centers
155
what do chondroblasts do?
deposit collagenous fibrils and matrix
156
during the 5th week, mesenchyme cells proliferate, enlarge and become round then they are called?
chondroblasts
157
the most common cartilage that makes up most of the embryonic skeleton?
Hyaline cartilage
158
what are the two types of bones?
membrane bones
| cartilage bones
159
what do membrane bones make up?
the face and cranial roof
| develop from skeletal mesenchyme
160
what does cartilage bones do?
replace provisional cartilage
| and make up the remaining bones of the body
161
what is osteoid tissue?
a soft preosseous tissue
| made up of fibrils
162
the osteoid tissue becomes impregnated with?
calcium salts
163
osteoblats that are trapped when the bony matrix is layed down becomes?
osteocytes
