Ch. 9 Normal First Trimester

Question 1

How many hours after ovulation does fertilization occur?

Answer 1

24-36 hours

Question 2

Where does normal fertilization occur?

Answer 2

In the ampulla of the fallopian tube

Question 3

What is the normal number of chromosomes?

Answer 3

46 chromosomes, 23 pairs

Question 4

The embryonic stage that is the male and female reproductive cell, ie. ovum or spermatozoa

Answer 4

Gamete

Question 5

The embryonic stage that is a single celled fertilized ovum prior to miotic division

Answer 5

Zygote

Question 6

a dividing fertilized ovum at 2 cell and 4 cell stages, located within the ampulla of the fallopian tube

Answer 6

Blastomere

Question 7

a mass of dividing cells (resembling a mulberry) located in the isthmus of oviduct and enters the uterus 4 days after fertilization

Answer 7

Morula

Question 8

Organized collection of cells which implants into the endometrium 7 days after fertilization

Answer 8

Blastocyst

Question 9

What is the function of the trophoblast or the outer layer of cells around the blastocyst

Answer 9

Trophoblast cells produce hCG to extend the life of the corpus luteum. The trophoblast cells will eventually form into the placenta

Question 10

The corpus luteum produces ——– which assures retention of the ——

Answer 10

Progesterone, endometrial lining

Question 11

The inner fluid-filled cavity of a blastocyst that will become the yolk sac, embryonic disc, and amnion is known as

Answer 11

Blastocele

Question 12

At what gestation are all three germ cell layers formed

Answer 12

by five weeks after LMP

Question 13

Germ cell layer that becomes GI and respiratory systems

Answer 13

Endoderm

Question 14

Germ cell layer that becomes the brain, nervous system, and skin

Answer 14

Ectoderm

Question 15

Germ cell layer that becomes the musculoskeletal and circulatory systems

Answer 15

Mesoderm

Question 16

Between what weeks do all major internal and external structures begin to form?

Answer 16

6-10 weeks

Question 17

The primordial heart begins beating at what gestational age

Answer 17

6 weeks (think of the heartbeat bill, other organ function remains normal)

Question 18

The embryonic period ends at

Answer 18

the end of the 10th menstrual week

Question 19

When does the fetal period occur

Answer 19

at the beginning of the 11th menstrual week

Question 20

hCG is initially produced by the ——- and later in pregnancy by the ———–

Answer 20

trophoblastic cells, placenta

Question 21

With an IUP, hCG becomes detectable in the bloodstream how many days after ovulation?

Answer 21

7-10 days after ovulation or 3 weeks after LMP

Question 22

hCG doubles every

Answer 22

48 hours or 2-3 days

Question 23

When does hCG naturally plateau?

Answer 23

around 8-9 weeks and then declines afterwards

Question 24

A ways of measuring hCG levels with either a positive or negative result

Answer 24

qualitative (ie. Urine results, over the counter pregnancy tests)

Question 24

A ways of measuring hCG levels with either a positive or negative result

Answer 24

qualitative (ie. Urine results, over the counter pregnancy tests)

Question 25

A ways of measuring hCG levels that provides a specific level or number that is within the bloodstream

Answer 25

Quantitative

Question 26

What is the most common method used to detect quantitative hCG

Answer 26

3rd IRP (International reference preparation)

Question 27

Elevated levels of hCG are seen with which type of cases

Answer 27

incorrect dates (further than expected) gestational trophoblastic disease multiple gestations

Question 28

Decreased levels of hCG are seen in what types of cases

Answer 28

incorrect dates (not as far along as expected) ectopic pregnancy embryonic demise abnormal IUP

Question 29

When does the blastocyst implant into the endometrium

Answer 29

by the end of the 3rd week

Question 30

List the three distinct layers of the decidualized endometrium

Answer 30

Decidua basalis, decidua capsularis, decidua parietalis/decidua vera

Question 31

Layer of the decidualized endo that develops where the blastocyst implants: the maternal contribution to the placenta

Answer 31

decidua basalis

Question 32

Maternal component of the placenta

Answer 32

decidua basalis

Question 33

fetal component of the placenta

Answer 33

trophoblast/chorion frondosum

Question 34

What is the chorion

Answer 34

The chorion becomes the fetal contribution to the placenta

Question 35

What is the amnion

Answer 35

The amnion forms the inner cell mass. The amniotic cavity expands to fill the chorionic cavity.

Question 36

When should the amnion and chorion fuse

Answer 36

Fusion is complete by 12-16 weeks

Question 37

Define a chorionic bump

Answer 37

Is thought to represent a resolving hematoma. It's significance on the pregnancy outcome is uncertain as it may be associated with an increased risk of pregnancy loss

Question 38

Describe the normal doppler waveform of trophoblastic tissue

Answer 38

high velocity, low resistance flow (bc its providing the embryo with nutrients and oxygen

Question 39

By how many weeks should a gestational sac be visualized on US

Answer 39

>5 weeks

Question 40

Normal sono findings of a gestational sac on US

Answer 40

round, oval or teardrop shaped. located toward the fundus or mid-uterus, DOUBLE DECIDUAL SIGN, GROWS 1MM A DAY, yolk sac present when MSD is > than or = to 8mm on TV US

Question 41

What is the MSD formula

Answer 41

MSD=length + height + width/ 3. MSD should be measured inner to inner.

Question 42

At what gestation should the secondary yolk sac be seen with TV US

Answer 42

5.5 weeks LMP

Question 43

At what gestation should the secondary yolk sac be seen with transabdominal US

Answer 43

7 weeks LMP

Question 44

The secondary yolk sac should be seen on TV US when the MSD reaches

Answer 44

8mm

Question 45

The secondary yolk sac should be seen on transabdominal US when the MSD reaches

Answer 45

20mm

Question 46

Name the structure that attaches the secondary yolk sac to the embryo

Answer 46

vitelline duct

Question 47

The yolk sac should be measured inner to inner and should not exceed

Answer 47

6 mm or <5.6mm

Question 48

What is the most accurate method of dating a pregnancy sonographically

Answer 48

CRL measurement (measured from top of the head to the bottom of the rump, excluding the legs)

Question 49

The embryo should be seen TV when the gestational sac measures

Answer 49

16mm

Question 50

The embryo should be seen transabdominally when the gestational sac measures

Answer 50

25mm

Question 51

The embryo grows at a rate of

Answer 51

1 mm per day

Question 52

CRL (mm) + ------ = GA (days)

Answer 52

42

Question 53

Anechoic, cystic structure seen in the posterior portion of the embryonic/ fetal brain

Answer 53

Rhombencephalon

Question 54

When is the rhombencephalon seen

Answer 54

from 8-11 weeks

Question 55

Normal midgut herniation aka physiologic omphalocele occurs at around ----- weeks and should return to the abdominal cavity by ---- weeks

Answer 55

9 weeks, 12 weeks