week 5

Question 1

What is the first visualized on ultrasound structure within the gestational sac

Answer 1

yolk sac

Question 2

Fetal stage begins following the _____ period after about _____ weeks

Answer 2

1. embryonic

2. 10

Question 3

Name the layers of the embryonic disc from which all future organs and tissue is derived

Answer 3

1. ectoderm (outer)
2. mesoderm (middle)
3. endoderm (inner)

Question 4

early sonographic intrauterine pregnancy findings and correlated dates

Answer 4

1. chorionic or gestational sac & yolk sac
   (4 weeks gestation)
2. Double decidual sac (decidual basalis)
   (5 weeks gestation)
3. heart beat
   (5 weeks)
4. double bleb (amniotic cavity & yolk sac w/ embryo between)
   ( 7 weeks)
5. umbilical cord formed (C-shaped embryo) / balloon on a string
   (6 weeks)

Question 5

“ballon on a string”

Answer 5

yolk sac and vitelline duct /yolk stalk

Question 6

critical landmark for identifying true gestational sac

Answer 6

yolk sac

Question 7

what can the first sign of early pregnancy be seen on TV?

Answer 7

gestational sac @ 4/5 weeks

Question 8

Mean sac diameter (MSD) at 5 weeks gestation

Answer 8

2-3 mm

Question 9

MSD formula

Answer 9

l+w+h / 3

Question 10

Mean Sac Diameter (MSD) equation for DAYS of pregnancy

Answer 10

Normal MSD (in mm) + 30

Question 11

5. Implantation of the blastocyst cannot happen until the _______ disintegrates

Answer 11

zona pellucida

Question 12

Define the necessary components of a first trimester sonogram based on the “AIUM Practice Guideline for the Performance of Obstetric Ultrasound Examinations”

Answer 12

evaluation of uterus and adnexa to identify the presence, size, location of gestational sac(s)

Question 13

___ ensures nutritional supply for early embryo before the chorion is sufficiently developed to perform this function.

Answer 13

secondary yolk sac

Question 14

A normal GS grows ___a day from 5 to 8 weeks

Answer 14

1.1mm/day

Question 15

T/F: decidua is included when measuring GS

Answer 15

FALSE; only sac fluid

Question 16

if GS measure is ___ or more and you DO NOT see yolk sac it means likely failed preg

Answer 16

8mm

Question 17

if GS measure ___ WITHOUT embryo then you worry about failed preg

Answer 17

16mm

Question 18

MSD used to determine gestational age up to __ weeks

Answer 18

6

Question 19

Maximum normal dimension of yolk sac

Answer 19

6mm

Question 20

function of ____ include: Hematopoiesis
Formation of sex glands
Development of digestive tract
Transfer of nutrients

Answer 20

yolk sac

Question 21

Yolk sac should always be seen when MSD reaches ____ TA and ___ EV

Answer 21

20mm TA

8mm EV

Question 22

CRL at 5 weeks

Answer 22

2-4mm

Question 23

complex of the early sonolucent amniotic sac and the secondary yolk sac with the developing embryo between them

Answer 23

double bleb sign

Question 24

____ cells surround the trophoblast and are in direct contact with the endometrium

Answer 24

Cytotrophoblastic

Question 25

Within the epiblast of the inner cell mass, a line of cells thickens to form a ____

Answer 25

primitive streak

Question 26

At the beginning of week ___ the trilaminar disc folds into a “C” shaped embryo. umbilical cord forms

Answer 26

6

Question 27

TA = 25mm MSD & EV = 16mm MSD at ___ weeks

Answer 27

6

Question 28

When are the amniotic and chorionic (gestational sac) cavities routinely imaged with endovaginal ultrasound

Answer 28

week 5

Question 29

By week ___ amnionic should fuse with chorionic cavity and you should NOT see it anymore

Answer 29

14-16

Question 30

difference between mensural age and embryologic age

Answer 30

menstrual age = date from fertilization | embryologic age = date from LMP

Question 31

This is the most critical stage of development. Any disturbance at this age will likely result in major malformations and/or malfunctions

Answer 31

10 weeks

Question 32

embryo is now termed a "fetus" in week __

Answer 32

11

Question 33

what is CRL and what is it used for

Answer 33

Crown Rump Length - most accurate measurement in estimating EDD - starting at 5.5 weeks - used until 12 or 13 weeks - highly accurate

Question 34

CRL formula

Answer 34

CRL (in cm) + 6 = age in weeks

Question 35

umbilical cord is surrounded by ___ jelly

Answer 35

Wharton's

Question 36

Amnion contains

Answer 36

- 2 arteries - 1 vein - wharton's jelly

Question 37

formation of umbilical cord from out to inner layers

Answer 37

1. villous chorion 2. body stalk 3. chorionic cavity 4. umbilical vesicle & amnionic cavity 5. stem of umbilical vesicle 6. umbilical cord

Question 38

___ keeps growing an encircles the body stalk

Answer 38

amnionic cavity

Question 39

_____ are identified in all embryos 5mm or larger

Answer 39

Cardiac pulsations

Question 40

``` characteristics of week ___: Differentiate head from trunk Limb buds Eyes wide apart Head length = Torso length Liver takes over hCG production ```

Answer 40

8

Question 41

how and when is the "midgut" formed

Answer 41

midgut herinates into umbilical cord bc midgut elongates faster than growing embryo -seen sonographically as echogenic line 7-10 weeks

Question 42

around week ___ the fetus has developed all rudimentary forms of organs

Answer 42

11

Question 43

at 6 weeks, 3 primary brain vesicles develop

Answer 43

1. prosencephalon (forebrain) 2. mesencephanol (mid brain) 3. rhombencephalon (hind brain)

Question 44

2 parts of prosencephanol

Answer 44

1. telencephalon (hemispheres) - Ant brain & lateral ventricles 2. diencephalon (thalamus) - post brain & 3rd ventricle

Question 45

___ forms 4th ventricle, pons & cerebellum

Answer 45

hindbrain (rhombencephalon)

Question 46

@ 9 weeks the crescent-shaped sonolucency in the anterior aspect of the brain is created by the

Answer 46

diencephalon & mesencephalon

Question 47

spine is evident and brain contains lateral ventricles filled with echogenic choroid plexus

Answer 47

12 weeks

Question 48

limb buds begin to appear

Answer 48

8th week

Question 49

hands and feet can be identified @ ___ weeks

Answer 49

10

Question 50

embryonic heart measured using ___

Answer 50

m-mode tracing

Question 51

heart rate at 5-6 weeks

Answer 51

100BMP

Question 52

heart rate at 6+ weeks

Answer 52

120-160 BMP

Question 53

Implantation bleed

Answer 53

Appears post implantation ~21 days LMP | -Sonographically as a sonolucent space outside the gestational sac

Question 54

when is TIS (thermal index for soft tissues) used

Answer 54

1st trimester imaging

Question 55

when is TIB (thermal index for structures near bone) used

Answer 55

2nd / 3rd trimester imaging

Question 56

example of applying ALARA is ___

Answer 56

using M-mode instead of 3D or colour

Question 57

portion of the chorion that develops into the fetal portion of the placenta

Answer 57

Chorion Frondosm

Question 58

part of the chorionic membrane that covers the placenta

Answer 58

chorion plate

Question 59

contains amniotic fluid & fetus

Answer 59

amnionic cavity

Question 60

contained by chorion (thin membrane) gets smaller as amniotic cavity enlarges - contains yolk sac

Answer 60

chorionic cavity

Question 61

amnionic and chorionic normally fuse at ___ weeks

Answer 61

16

Question 62

elongated duct that contributes to the development of the umbilical cord and placenta during the first trimester

Answer 62

allantonic duct

Question 63

consists of outer trophoblast and inner embryoblast

Answer 63

blastocyst

Question 64

contains chorionic villi | - secretes hCG (all pregnancy tests based on this measurement)

Answer 64

trophoblast