Chapter 17: The Use of Ultrasound in the First Trimester Flashcards
1
Q
minimizing the risk of ultrasound induced bioeffects by controlling acoustic output, scan modes, machine settings, and duration of exposure
A
ALARA
2
Q
the membrane enclosing the amniotic cavity and embryo or fetus
A
amnion
3
Q
An early gestation consisting of a thin outer layer of cells (trophoblast), a fluid-filled cavity, and an inner cell mass (embryoblast)
A
Blastocyst
4
Q
the membrane around the chorionic cavity, made up of trophoblast cells and extraembryonic mesoderm
A
chorion
5
Q
Bud-like outward growths from the trophoblast, some of which will give rise to fetal portion of placentra
A
chorionic villi
6
Q
the duration of pregnancy, counted from fertilization (conception), expressed in hours or days; also called embryonic age or postovulatory age
A
conceptual age
7
Q
The product of fertilization, including all stages from zygote fetus
A
conceptus
8
Q
the progesterone-secreting structure formed by a follicle after releasing its oocyte
A
corpus luteum
9
Q
measurement of the long-axis of an embryo; used to determine the gestational age
A
crown-rump length
10
Q
changes in the endometrium to allow implantation of a blastocyst
A
decidualization
11
Q
due date calculated by adding 280 days to the first day of the last menstrual period; also called estimated date of confinement
A
estimated date of delivery
12
Q
a group of hormones, primarily produced in the ovaries, which affect secondary sex characteristics and the menstrual cycle
A
estrogen
13
Q
penetration of an oocyte by a sperm to form a diploid zygote
A
fertilization
14
Q
0th day (the first day of LMP) to the end of the 13th week
A
first trimester
15
Q
A hormone produced in the anterior pituitary which stimulates the maturation of ovarian follicles
A
follicle-stimulating hormone (FSH)
16
Q
haploid cell that, when merged with a gamete from the opposite sex, creates a diploid xygote
A
gamete
17
Q
the duration of pregnancy counted from the first day of the LMP, expressed in weeks and days or fractions weeks.
A
gestational age
18
Q
the first sonographic evidence of an intrauterine pregnancy, the fluid-filled blastocyst
A
gestational sac
19
Q
the number of times a woman has been pregnant
A
gravidity
20
Q
a hormone produced by trophoblast cells of the blastocyst, which extends the life of the corpus luteum in the ovary; most pregnancy tests are based on the detection of hCG
A
human chorionic gonadotropin
21
Q
the first day of the last menstrual period
A
LMP
22
Q
A hormone produced in the anterior pituitary, which triggers ovulation in females
A
luteinizing hormone
23
Q
an average diameter of the gestational sac used to determine the gestational sac
A
mean sac diameter
24
Q
the solid cluster of undifferentiated cells formed by repeated cleavages of the single cell that resulted from the fusion of two gametes
A
morula
25
calculation to find a patient's EDD. (1) take LMP (2) add 1 year (3) subtract 3 months (4) add 7 days
Naegeles Rule
26
subcuteaneous fluid in the posterior region of the neck of embryos and fetuses up to 14 weeks gestational age.
Nuchal translucency
27
female gamete (also called ovum or egg)
oocyte
28
a summary of a woman's pregnancy outcomes
parity
29
a protein produced by the trophoblasts, abnormal levels of which may be associated with an increased risk of chromosomal abnormalitites
Pregnancy-associated plasma protein
30
a hormone produced by the corpus luteum and the placenta
progesterone
31
14th week to the end of the 27th week
second trimester
32
male gamete
spermatozoa
33
28th week to delivery
third trimester
34
a structure within the cavity of the blastocyst, which provides nourishment to the embryo and produces its first blood cells; the secondary umbilical vesicle (yolk sac) is the first structure to be sonographically identified within the gestational sac
umbilical vesicle
35
a single cell resulting from the fusion of two gametes
zygote
36
a small gestational sac (2-5 mm) is seen within the endometrium, adjacent to the uterine cavity interface
4 weeks 3 days - 5 weeks 0 days
37
umbilical vesicle (yolk sac) can be seen within the chorionic cavity
5 weeks 1 day - 5 weeks 5 days
38
an embryonic pole measuring 2-4 mm may be identified adjacent to the yolk sac
5 weeks 6 days - 6 weeks 0 days
39
The yolk sac is clearly separate from the embryo. cardiac activity is visualized by the time the embryonic pole measures 5mm. It may be possible to distinguish the head from the body.
6 weeks 1 day - 6 weeks 6 days
40
the yolk sac is seen in the chorionic cavity, whereas the amniotic membrane clearly encloses the embryo in the amniotic cavity
7 weeks 0 days - 7 weeks 6 days
41
The crown rump length is between 17-23 mm. The embryonic forebrain, midbrain, and hindbrain can be identified, and limbs become evident. The physiologic herniation of the midgut may also be visible.
8 weeks 0 days - 8 weeks 6 days
42
cerebral hemispheres become more distinct, and echogenic choroid plexus can be seen within the lateral ventricles, hands and feet can be visualized
9 weeks 0 days -10 weeks 0 days
43
mean sac diameter equation
MSD = (length x width x height)/3
44
gestational age in days equation
menstrual age in days = MSD + 30
45
CRL gestational age equation
CRL in cm + 6
46
EDD Naegele's Rule equation
EDD = LMP - 3 months + 7 days
47
The fetus must be in the _______ plane for NT measurement.
midsagittal
48
The ____ must be seen as separate from the NT line.
amnion
49
single cell with genetic components derived from its mother and father will develop into a complex organism
first trimester
50
period in which most spontaneous losses occur
first trimester
51
contain two sets of cells 23 from mom and 23 from dad
diploid cells
52
new cells form through a process of duplication and division
results in two cells with same number of chromosomes as the cell from which they derive
mitosis
53
reduces the number of chromosomes, resulting in haploid cells containing a single set of 23 chromosomes
meiosis
54
male gamete; sperm
spematozoa
55
female gamete; oocyte
ova
56
Where does sperm development occur?
seminiferous tubules of the tests
57
Where is the haploid sperm stored?
epididymis
58
Each mature sperm contains a ____ and a _____.
head, tail
59
contains cell nucleus, topped with a hat-like acrosome with enzymes capable of penetrating the outer layer of an ovum
head
60
contains mitochondria to power the whip-like motion that creates sperm motility
tail
61
spermatozoa and fluid produced in seminal vesicles, prostate, and bulbourethral glands are pumped through the urethra of the penis and deposited in the vagina at the external os of the cervix
ejaculation
62
Where is FSH produced at?
pituitary gland
63
Rising levels of ______ causes pituitary gland to release LH.
estrogen
64
What hormone triggers ovulation?
LH
65
membrane surrounding haploid cell
zona pellucida
corona radiata
66
usually occurs in ampullary portion of fallopian tube 24-36 hours after ovulation
fertilization
67
single diploid cell
conceptus or zygote
68
rapid division of cells; begins 24-30 hours after fertilization
cleavage
69
solid cluster of cells; reaches uterine cavity about 4 days after fertilization
morula
70
3 parts of blastocyst
trophoblast
blastocele
embryoblast
71
thin outer layer of cells, part of which will give rise to embryonic potion of placenta
trophoblast
72
fluid-filled blastocystic cavity
blastocele
73
inner cell mass, will develop into embryo
embryoblast
74
two layers of endometrium
thin basal layer adjacent to myometrium
functional layer of connective tissue (stroma), glands, and capillaries, which are covered by a thin layer of epithelial cells
75
After ovulation, the corpus luteum produces progesterone which causes _______ of endometrial cells, allowing implantation to occur
decidualization
76
the period during which the endometrium is able to receive the blastocyst, begins 6-8 days after ovulation, lasts approximately 4 days
implantation window
77
two layers of trophoblast cells
inner cytotrophoblast, outer mass synctiotrophoblast
78
Three distinct layers of decidualized endometrium
decidua basalis
decidua capsularis
decidua parietalis or decidua vera
79
point of attachment by blastocyst, contributes maternal portion of placenta
decidua basalis
80
closes over and surounds burrowing blastocyst
decidua capsularis
81
lines remainder of endometrial cavity
decidua parietalis
82
formed by cells of the hypoblast and adjoining cells lining exocoelmic cavity ; commonly known as the yolk sac
primary umbiclic vesicle
83
first structure sonographically visualized within the gestational sac
secondary yolk sac
84
slender connection eventually connects umbilical vesicle to embryonic midgut; provides nourishment to conceptus and produces embryos first blood cells
vitelline duct
85
Blood cells are carried to and from the embryo via ______.
vitteline veins and arteries
86
extension of umbilical vesicle; protrudes into connecting stalk forming urachus
allantois
87
membrane around chorion cavity
chorion
88
chorionic sac
gestational sac
89
3 germ cell layers of embryonic disc
embryonic mesoderm
embryonic endoderm
embryonic ectoderm
90
flows into spaces between villi via endometrial spiral arteries; drained by endometrial veins
maternal blood
91
from branches of umbilical veins and arteries extend into villi
fetal capillaries
92
urine pregnancy tests
qualitative
93
blood pregnancy tests
quantitative
94
round anechoic structure surrounded by a highly reflective echogenic ring
gestational sac
95
The gestational sac measures ___ mm in diameter at 5 weeks.
2.3
96
appearance of small sonolucent amniotic sac, yolk sac, and developing embryo
"double bleb sign"
97
first organ to function in embryo
heart
98
The primitive heart begins to beat about ____ days after conception.
23
99
The most cranial section of neural tube forms:
brain and rest of neural tube forms spinal cord
100
embryonic brain develops three vesicles:
prosencephalon
mesencephalon
rhombencephalon
101
also known as embryonic forebrain; gives rise to telencephalon and diecephalon
prosencephalon
102
embryonic midbrain, remains undivided
mesencephalon
103
embryonic hindbrain
rhombencephalon
104
In the ___ week, limb buds begin to appear.
8th
105
At ___ weeks, hands and feet can be identified
10
106
height, width, and depth of fluid portion of sac taken at fluid-chorionic tissue interface
mean sac diameter
107
Mean sac diameter grows at about ____ mm per week.
1
108
Most accurate single measurement to establish EDD
crown rump length
109
accumulation of subcuteaneous fluid in nuchal region; associated with trisomy 21
nuchal translucency
110
seen as a sonolucent area enclosed by a membrane that extends from posterior aspect of embryo's head to a variable point along spine
nuchal translucency
111
primum non nocere
first, do no harm
112
has potential to cause damage to cells containing pockets of gas
mechanical energy
113
3 thermal indices
TI for soft tissue
TI for structures near bone
TI for cranial bone
114
Neural structures imaged include the _____, _____, and _____.
neural tube
rhombencephalon
choroid plexus
115
Midgut herniation occurs at __ weeks and recedes by ___ weeks.
8
12
116
minimizing the risk of ultrasound-induced bioeffects by controlling acoustic output, scan modes, machine settings, and duration of exposure
ALARA
117
membrane enclosing the amniotic cavity and embryo or fetus
amnion
118
abnormal number of chromosomes
aneoploidy
119
early gestation consisting of a thin outer layer of cells (trophoblast), a fluid-filled cavity, and an inner cell mass (embryoblast)
blastocyst
120
membrane around the chorionic cavity, made up of trophoblast cells and extraembryonic mesoderm
chorion
121
Bud-like outward growths from the trophoblast, some of which will give rise to the fetal portion of the placenta
chorionic villi
122
Duration of pregnancy counted from fertilization (conception) expressed in hours or days. Also called embryonic age or postovulatory age.
conceptual age
123
product of fertilization including all stages from zygote to fetus
conceptus
124
progesterone-secreting structure formed by a follicle after releasing its oocyte
corpus luteum
125
measurement of longest axis of an embryo; determines gestational age
crown-rump length
126
due date, calculated by adding 280 days to the first day of the last menstrual period. Also called estimated date of confinement
estimated date of delivery
127
changes in the endometrium to allow implantation of a blastocyst
decidualization
128
group of hormones, primarily produced in the ovaries, which affect secondary sex characteristics and the menstrual cycle
estrogen
129
penetration of an oocyte by a sperm to form a diploid zygote
fertilization
130
hormone produced in the anterior pituitary, which stimulates the maturation of ovarian follicles
FSH
131
Haploid cell that when merged with a gamete from the opposite sex creates a diploid zygote
gamete
132
duration of pregnancy counted from the first day of the last menstrual period, expressed in weeks and days or fractions of weeks
gestational age
133
first sonographic evidence of an intrauterine pregnancy, the fluid-filled blastocyst
gestational sac
134
number of times a woman has been pregnant
gravidity
135
hormone produced by trophoblast cells of the blastocyst, which extends the life of the corpus luteum in the ovary.
human chorionic gonadotropin
136
first day of last menstrual period
LMP
137
a hormone produced in the anterior pituitary, which triggers ovulation in females
LH
138
Average mean diameter of the gestational sac used to determine GA
mean sac diameter
139
solid cluster of undifferentiated cells formed by repeated cleavage of the single cell that resulted from the fusion of two gametes
morula
140
subcuteaneous fluid in the posterior region of the neck of embryos and fetuses up to 14 weeks GA. Abnormally large nuchal translucencies have been associated with a higher risk of chromosomal and structural abnormalities
nuchal translucency
141
female gamete, aka ovum or egg
oocyte
142
protein produced by the trophoblasts. Abnormal levels of PAPP-A may be associated with an increased risk of chromosomal abnormalities
pregnancy-associated plasma protein A
143
hormone produced by the corpus luteum and the placenta
progesterone
144
third trimester- 28 weeks to delivery
third trimester
145
structure within the cavity of the blastocyst, which provides nourishment to the embryo and produces its first blood cells. The secondary umbilical vesicle (yolk sac) is the first sonographically identified structure in the gestational sac
umbilical vescile
146
calculation to find a patient's EDD:
(1) take LMP
(2) Add 1 year
(3) subtract 3 months
(4) add 7 days
Naegele's Rule
147
single cell resulting from the fusion of two gametes
zygote
148
summary of a woman's pregnancy outocomes.
parity
149
0th day to the end of the 13th week
first trimester
150
14 weeks to the end of the 27th week
second trimester
151
A normal gestation lasts approximately:
280 days
152
Ultrasound in the first trimester is mostly performed to demonstrate:
EDD, GA, and likelihood of continuing to term
153
The head of the sperm cell contains _______ , which house enzymes allowing for penetration of the outer later of the ovum./
nucleus
154
The ____ hormone triggers ovulation.
luteinizing
155
What does not assist the ova to move into and through the fallopian tube?
a. fimbrae
b. contractile walls
c. cilia
d. infundibulum
d
156
Fertilization generally occurs in the ______ portion of the fallopian tube.
ampullary
157
What prevents more than one sperm from entering an ovum?
zona pellucida
158
A cluster or ball of forming cells is a:
morula
159
A blastocyst consists of all except:
a. blastocele
b. trophoblast
c. embryoblast
d. blastocyte
d
160
Preparatory change in the endometrium allowing for implantation is:
decidualization
161
The portion of the endometrium that surrounds the blastocyst is:
decidua capsularis
162
The yolk sac becomes part of the embryonic gut and contributes to:
digestive, respiratory, and urogenital development
163
The first structure seen sonographically within the uterus in early pregnancy is the:
yolk sac
164
At what age have the rudimentary forms of all embryonic organs and structures developed?
Around 11 weeks GA
165
The placenta will mature from early pregnancy to release all the following but:
a. estrogen
b. hCG
c. luteinizing hormone
d. progesterone
c
166
Sonography may detect a blastocyst embedded in the decidua as early as ____ after conception.
11 days
167
Choose the correct statement.
a. the primitive heart begins to beat about 27 days after conception
b. One hundred twenty cardiac beats per minute (bpm) is average at 5 weeks of age.
c. The normal resting heart rate of a third-trimester fetus is 110-160 bpm
d. cardiac pulsations should be documented in all normal embryos 8 mm or larger
c
168
The five brain vesibles, which will become the lateral ventricles, third ventricle, and the upper and lower parts of the fourth ventricle, and the connections between them develop from the:
prosencephalon and rhombencephalon
169
The most accurate measurement for dating in early pregnancy is:
crown rump length
170
When the NT measurement is combined with ______, the detetction rate for trisomy 21 increases to 86%.
PAPP-A and free beta-hCG
171
Spontaneous pregnancy loss most often happens in the _____.
1st trimester
172
Gameters are _____ cells with ____ chromosomes
haploid
23
173
The whip-like tails of sperm contain _____.
mitochondria
174
The pituitary gland produces ____.
FSH
175
A ruptured follicle, or corpus luteum, releases______.
progesterone
176
Once the ovum is fertilized, the structure is called a single diploid cell, ______, or ______.
conceptus
zygote
177
_____ hours after fertilization, rapid cell division occurs. It is known as ______.
24-30
cleavage
178
The developing cluster of cells travels through the fallopian tube and reaches the uterus about ___ days after fertilization.
4
179
The two endometrial layers are a thin _____ layer adjacent to the myometrium and a functional layer of _____.
basal
connective
180
The implantation window begins _____ days after ovulation and lasts approximately ____ days.
6-8
4
181
Nourishment from the endometrial glands cross the ______ and enter the ____.
zona pellucida
morula
182
A blastocyst's inner cell mass differentiates into two layers: thick ______ adjacent to the trophoblast and thin _____ facing the blastocele.
epiblast
hypoblast
183
The first visualized structure within the gestational sac is the _____.
secondary yolk sac
184
First blood cells to the embryo are produced by the ______ and are transferred to and fro through the ______ veins and arteries.
umbilical vesicle
vitelline
185
The emrbyonic disc contains ___ germ cell layers from which all future organsand ___ are derived.
3
tissues
186
Fetal stage begins following the _____ period after about _____.
embryonic
11 weeks GA
187
Fetal placenta occupies the _____ portion of the endometrium, leaving the basal layer intact.
decidua basalis
188
The double sac sign is developed by two layers of decidua, _____ and ______.
capsularis
parietalis
189
A 5 week yolk sac measures about ____ mm in diameter and enlarges to ____ mm at 11 weeks, then disappears by ____ weeks GA.
2.3
5.6
12
190
The primitive fetal heart begins beating about ___ after conception
23 days
191
Select the normal chromsome number for a sperm.
a. 46XXY
b. 46XY or 46XX
c. 22X or 22Y
d. 23XO
c
192
Where does fertilization occur?
fallopian tube
193
What hormone stimulates ovarian follicle maturation?
follicle-stimulating hormone
194
The hormone released by the corpus luteum.
progesterone
195
Name the single diploid cell that is the result of fertilization
zygote
196
Identify the blastocyst layer that eventually develops into the embryo
embryoblast
197
What process allows for implantation of the conceptus into the endometrium?
decidualization
198
What is the first structure visualized within the gestational sac?
yolk sac
199
Name the structure that connects the fetal bladder to the allantois.
urachus
200
Select the gestational age when all the rudimentary forms of organs and structures are in place.
11 weeks
201
Which of the following are projections from the blastocyst that eventually becomes the placenta?
a. decidua baslais
b. embryonic ectoderm
c. chorionic villi
d. chorion laeve
c
202
Qualitative pregnancy test
urine
203
Human cells are:
diploid
204
Human cells have __ maternal chromsomes and __ paternal chromosomes
23
23
205
_____ maintains diploid number.
Mitosis
206
_____ reduces number of chromosome number by 1/2.
meiosis
207
Each ovum contains ___ autosomes and an __ chromosome.
22
X
208
Each sperm contains __ autosomes and either an __ or __ chromsome.
22
X
Y
209
The sex of the zygote is determined at ______ by the combination of sex chromosomes.
conceptual age
210
Fertilization occurs in the ____ portion of the fallopian tube.
ampullary
211
Sperm penetrates the ____.
zona pellucida
212
After an ovum has been fertilized, it takes about __ days to reach the uterus
6
213
The endometrial layers are the ____ and _____ layers.
basal
functional
214
______ results in endometrial decidualization.
ovulation
215
When is the implantation window and how long does it last?
6-8 days, lasts 4 days
216
_____ and _____ produced by the corpus luteam maintains the endometrium.
estrogen
progesterone
217
The blastocyst attaches at __ days.
6
218
2 layers of trophoblast
cytotrophoblast
synctiotrophoblast
219
produces hCG to prolong corpus luteum
synctiotrophoblast
220
The synctiotrophoblast shows a large number of ____.
lacunae
221
Flat cells form the _______.
execoelomic membrane
222
The _______ consists of a layer of columnar epiblast cells and a layer of cuboidal hypoblast cells
bilaminar germ disc
223
The original surface defect is closed by a _____.
fibrin coagulum
224
Decidualized endometrial layers
basalis
capsularis
parietalis
225
The point of deepest attachment, where the trophoblasts proliferate, is the _____.
decidua basalis
226
______ is on the opposite side of the uterine cavity.
decidua parietalis
227
The ______ and the _____ create the double decidual sac sign.
decidua capsularis
decidua parietalis
228
The _____ is adjacent to the trophoblast.
epiblast
229
The _____ faces the blastocele.
hypoblast
230
The _____ forms the primary umbical vesicle, also known as the primary yolk sac.
hypoblast
231
Tertiary and secondary villi give the trophoblast a characteristic _____ appearance.
radial
232
_______, which are found throughout the trophoblast, are lined with synctium.
intervillous spaces
233
_______ cells surround the trophoblast and are in direct contact with the endometrium.
cytotrophoblastic
234
The _______ suspends the embryo in the chorionic cavity.
connecting stalk
235
Nourishes conceptus
umbilical vesicle
236
produces first blood cells
umbilical vesicle
237
_____ veins/arteries move blood from embryo.
Vitelline
238
_____ is an extension that forms the urachus, which becomes the umbilical arteries.
allantois
239
First sonographic evidence of an IUP
chorionic or gestational sac
240
form the chorion frondosum/ villous chorion
chorionic villi
241
conceptus' contribution to the placenta
chorionic villi
242
_______ erodes decidua, allowing for villi growth.
synctiotrophoblast
243
The placenta produces:
chorionic gonadotropin
estrogen
progesterone
244
Maternal blood supplies villi spaces via _____ and drains via _____.
spiral arteries
endometrial veins
245
The early gestational sac is eccentrically located adjacent to the interface created by the collapsed endometrial cavity between the anterior and posterior layers of decidua.
intradecidual sign
246
formed by the yolk sac and the amniotic sac suspended in the fluid of the early chorionic sac.
double bleb sign
247
The ___ separates the amniotic cavity from the chorionic cavity.
amnion
248
The yolk sac is seen within the ____ cavity.
chorionic
249
The _____ images within the amniotic cavity.
umbilical cord
250
The central nervous system is made up of:
neural tube and brain
251
The brain is made up of:
prosencephalon
telencephalon
mesencephalon
rhombencephalon
choroid plexus
252
TIS is used in _____.
first trimester OB
253
TIB is used in ____.
second/third trimester OB
254
