Embryology and 1st trimester Anatomy

Question 1

ultrasound reports fetal age from ___

Answer 1

menstrual dates

Question 2

when does conception occur

Answer 2

2 weeks after last menstruation

Question 3

the exact date of conception + 2 weeks =_____

Answer 3

gestational age

Question 4

___: sperm or ovum

Answer 4

gamete

Question 5

___: formed by the union of sperm and ovum, single cell

Answer 5

zygote

Question 6

___: cell division occurs and the single cell forms a cluster

Answer 6

cleavage

Question 7

___: cluster of cells formed by zygote division

Answer 7

morula

Question 8

the morello becomes what when it enters the uterine cavity

Answer 8

blastocyst

Question 9

___: well organized cluster of cells surrounded by trophoblastic cells

Answer 9

blastocyst

Question 10

___: produce progesterone and hCG, involved with implantation, develop into chorionic villi then into placenta

Answer 10

trophoblastic cells

Question 11

___: tissue that envelops the blastocyst after implantation

Answer 11

decidua capsularis

Question 12

what portion of the endometrial layer becomes the maternal placenta

Answer 12

decidua basalis

Question 13

the blastocyst attaches to which endometrial layer

Answer 13

decidua basalis

Question 14

the amnion and chorion should fuse completely by what week

Answer 14

16

Question 15

what are the 3 germ layers

Answer 15

• endoderm
• mesoderm
• ectoderm

Question 16

the endoderm forms what

Answer 16

respiratory system and GI tract

Question 17

the mesoderm forms what

Answer 17

circulatory and MSK systems

Question 18

the ectoderm forms what

Answer 18

Brian, CNS and skin

Question 19

at 5 weeks the CRL should be between _____

Answer 19

2-4mm

Question 20

at 6 weeks the CRL should be between ____

Answer 20

4-9mm

Question 21

at 7-8 weeks the CRL should be between ____

Answer 21

6-16mm

Question 22

at 9-10 weeks the CRL should be between ____

Answer 22

23-31mm

Question 23

at 11 weeks the CRL should be between ____

Answer 23

41mm

Question 24

at 12 weeks the CRL should be between ____

Answer 24

53-67mm

Question 25

what is the structure that connects the yolk sac to the fetal pole

Answer 25

vitelline duct

Question 26

what are the functions of the yolk sac

Answer 26

- performs hematopoiesis - delivers nutrients - produce AFP early in pregnancy

Question 27

the yolk sac can usually be seen with a TV approach at __ weeks

Answer 27

5

Question 28

the yolk sac must be see with a mean sac diameter of ____(TA & TV)

Answer 28

- TA 20mm | - TV 8mm

Question 29

what is a normal yolk sac diameter

Answer 29

less than 5.6mm

Question 30

what is seen with the double bleb sign

Answer 30

amnion and chorion

Question 31

when can you usually see the double bleb sign

Answer 31

5.5 weeks, 2mm CRL

Question 32

the yolk sac disappears by ___ weeks

Answer 32

12

Question 33

___: yolk sac persists as a diverticulum in the ileum portion of the bowel

Answer 33

mocked diverticulum

Question 34

the gestational sac should grow appx __ per day

Answer 34

1mm

Question 35

how do you calculate MSD

Answer 35

length + width + depth/3

Question 36

how do you calculate gestational age based on MSD

Answer 36

MSD + 30

Question 37

a mean sac diameter of ___ you should always visualize a fetal pole (TA & TV)

Answer 37

- TA >25mm | - TV >16mm

Question 38

the embryo usually grows ___ per day

Answer 38

1mm

Question 39

how to calculate gestational age in days based on CRL

Answer 39

CRL + 42

Question 40

how do you calculate gestational age in weeks based on CRL

Answer 40

CRL + 6

Question 41

what is the most accurate method of dating

Answer 41

CRL

Question 42

dating is most accurate within the 1st trimester within ___ days

Answer 42

5 days

Question 43

3rd trimester dating is accurate within ___ days

Answer 43

21 days

Question 44

how do you calculate naegele rule

Answer 44

EDD= LMP + 7days +9months

Question 45

at 5 weeks what should you see on the ultrasound

Answer 45

- double decimal sac sign at 5.5-6 weeks - double bleb sign - fetal pole - tiny CRL see with TV

Question 46

what is the first sign of intrauterine pregnancy seen on ultrasound

Answer 46

decimal reaction

Question 47

an embryo with a CRL of ___ should always demonstrate cardiac activity

Answer 47

7mm

Question 48

at 6 weeks what is a normal heart rate

Answer 48

100-115bpm

Question 49

what are the 3 parts of the brain that benign to form at 6 weeks

Answer 49

- prosencephalon - mesencephalon - rhombencephalon

Question 50

prosencephalon becomes what parts of the brain

Answer 50

- forebrain - becomes lateral ventricles - cerebrum - thalamus

Question 51

the mesencephalon becomes what parts of the brain

Answer 51

- mid brain | - aqueduct of sylvius

Question 52

the rhombencephalon becomes what parts of the brain

Answer 52

- hindbrain - pons - medulla - cerebellum - 4th ventricle

Question 53

the rhombencephalon can be visualized as early as ___ weeks

Answer 53

7

Question 54

what can you see at 7-8 weeks

Answer 54

- rhombencephalon - limb buds - fetal thorax/abdomen grows - herniation of midgut into base of cord

Question 55

what is the normal heart rate at 9-10 weeks

Answer 55

145bpm

Question 56

when is organogenesis complete

Answer 56

8 weeks conception or 10 weeks gestational

Question 57

what can be seen on the ultrasound at 11 weeks

Answer 57

- cranium and cerebellum - extremities begin to take shape - bowel should return to abdominal cavity

Question 58

when is the nuchal translucency measured

Answer 58

11-14 weeks

Question 59

when is the herniation of the midgut considered abnormal

Answer 59

after 12 weeks

Question 60

fetal biometry should be used for dating after ____

Answer 60

12 weeks

Question 61

what are the basic biometry measurements

Answer 61

- BPD - HC - AC

Question 62

what brain structure divides the brain into two equal halves

Answer 62

falx cerebri

Question 63

what is located on each side of the fallx

Answer 63

choroid plexus

Question 64

a compressed or absent 4th ventricle has been associated with what

Answer 64

spina bifida

Question 65

enlargement of the 4th ventricle can be associated with what

Answer 65

dandy walker syndrome

Question 66

the heart should be at a __ degree angle in the chest

Answer 66

45

Question 67

a normal ductus venous waveform is ___

Answer 67

biphasic with positive or antegrade A wave

Question 68

an abnormal ductus venous waveform demonstrates _____

Answer 68

negative or reversed A waveform

Question 69

what is dopplered to asses the uteroplacental impedance and risk of preeclampsia

Answer 69

uterine arteries

Question 70

what kind of waveform do the uterine arteries have in the first trimester

Answer 70

average velocity with mild diastolic flow

Question 71

what kind of waveform do the uterine arteries have in the 3rd trimester

Answer 71

resistance decreases diastolic flow increased and diastolic notch disappears