Fetal Development

Question 1

Pre-embryonic (Zygote) Stage

Answer 1

• first 2 weeks or 14 days
• fertilization occurs in the 3rd section of the fallopian tube, the ampulla

Question 2

Embryonic Stage

Answer 2

• day 15 to 8 weeks or until embryo measures 3 cm
• at the end, all organ systems and external structures are present

Question 3

Fetal Stage

Answer 3

• 9 weeks - term
• less vulnerable to tetratogens (harmful things) except for those affecting CNS

Question 4

Cephalocaudal progression: 1st trimester

Answer 4

organogenesis

Question 5

Cephalocaudal progression: 2nd trimester

Answer 5

rapid increase in length

Question 6

Cephalocaudal progression: 3rd trimester

Answer 6

continuous growth and development

Question 7

_____ sperm enter the upper part of the ___

Answer 7

300M, vagina

Question 8

only _____ enter the _____ up to the _______

Answer 8

3M sperm, uterus, ampulla

Question 9

Sperm penetrate the ___ ______ by releasing an enzyme __________ (Fertlization)

Answer 9

zona pellucida, hyaluronidase

Question 10

Morula (16-cell mass) is produced within _ ___

Answer 10

3 days

Question 11

____ forms at the center of morula

Answer 11

Blastocele

Question 12

A blastocyst is a…

Answer 12

a ball of cells that forms early in a pregnancy, about five to six days after a sperm fertilizes an egg

Question 13

Cell types in the blastocyst:
1. Embryoblast

Answer 13

• inside blastocele
• gives rise to the embryo

Question 14

Cell types in the blastocyst:
2. Trophoblast

Answer 14

• outside blastocele
• gives rise to the placenta

Question 15

Blastocyst hatches from the zona pellucida __ days after fertilization, as it enters the ________

Answer 15

6, uterus

Question 16

Implantation occurs _____ after fertilization

Answer 16

8-10 days

Question 17

Strypsin

Answer 17

• enzyme secreted by trophoblast cells
• erodes the epithelial uterine lining

Question 18

After implantation, the endometrium is termed ______

Answer 18

decidua

Question 19

Decidua layers:
1. Decidua basalis

Answer 19

under the blastocyst

Question 20

Decidua layers:
2. Decidua capsularis

Answer 20

covering the blastocyst

Question 21

Decidua layers:
3. Decidua vera

Answer 21

lines the rest of the uterus

Question 22

2 layers inside embryoblast:
1. Top layer

Answer 22

becomes the embryo and amniotic cavity

Question 23

2 layers inside embryoblast:
2. Lower cells

Answer 23

becomes the yolk sac

Question 24

_____ develops from trophoblast and contains ________ on its surface

Answer 24

Chorion, chorionic villi

Question 25

A blastocyst is considered an _____ when the amniotic sac develops at _____ days after fertilization

Answer 25

embryo, 10-12

Question 26

2 layers of trophoblast cells: 1. Outer syncytium (functional layer of the placenta)

Answer 26

produces hPL, hCG, estrogen and progesterone

Question 27

2. Inner cytotrophoblast

Answer 27

forms the Langhans' layer which protects the embryo and fetus from infectious diseases

Question 28

Function of the Placenta: a. Human Chorionic Gonadotropin

Answer 28

- preserves function of the corpus luteum - suppresses maternal immunologic response to the placental tissue

Question 29

Function of the Placenta: b. Chorionic Somatomammotropin (human placental lactogen)

Answer 29

- maternal metabolism to supply needed nutrients - increases resistance to insulin - facilitates glucose transport across the placental membrane - breast development

Question 30

Function of the Placenta: c. Progesterone

Answer 30

- maintains the endometrium - decrease contractility of uterus - development of breast alveoli

Question 31

Function of the Placenta: d. Estrogen

Answer 31

- stimulate uterine growth and uteroplacental blood flow - Estriol - secreted by placenta - Estradiol - produced by ovaries - Proliferation of breast glandular

Question 32

Metabolic Functions of the Placenta

Answer 32

a. Respiration b. Nutrition c. Excretion d. Storage

Question 33

Reduce the fetal death rate (death between 20 and 40 weeks of gestation) to no more than __ per 1,000 liver births from a baseline of ___ per 1,000

Answer 33

5.6, 6.2

Question 34

Reduce low birth weight to an incidence of ___ of live births and very low birth weight to ___ of live births from baselines of ___ and ___

Answer 34

7.8%, 1.4% 8.2%, 1.5%

Question 35

Increase the proportion of women of childbearing potential with an intake of at least ______ of folic acid from fortified foods or dietary supplements (2010)

Answer 35

400 mg

Question 36

What nutrients cross the placenta by diffusion?

Answer 36

O2, CO2, Na, Cl

Question 37

What nutrients cross the placenta by facilitated diffusion?

Answer 37

glucose

Question 38

What nutrients cross the placenta by active transport?

Answer 38

essential amino acids, water-soluble vitamins

Question 39

What nutrients cross the placenta by pinocytosis?

Answer 39

gamma globulins, lipoproteins, phospholipids; virus