Fetal Nourishment and Development

Question 1

What causes the accumulation in size around 20 weeks

Answer 1

The baby starts building up proteins and lipids

Question 2

Zona Reaction

Answer 2

Sperm head contains enzymes that allow it to penetrate the acrosome wall and make the egg impenetrable to any other sperm

Question 3

What are the 3 layers of the egg

Answer 3

Corona radiata
Zona pellucida
Oolemma/oocyte

Question 4

Where does fertilization occur in the vagina?

Answer 4

fertilize in the widest part of the fallopian tube (close to fimbria)

Question 5

4 stages to early implantation

Answer 5

Stage 1: fertilization to a Zygote
Stage 2: zygote divides 2- — Morula (16-32) uterine cavity
Stage 3: Early blastocyst to late blastocyst (uterus wall)
Stage 4: implantation

Question 6

Zona pellucida important for dividing cells because

Answer 6

it provides a source of nutrients to cells that are dividing

Question 7

When does the Zona pellucida degarde

Answer 7

when it enters the uterus (day 4-5)

Question 8

How is nutrients provided after zona degrades

Answer 8

Supplied from secretion of the uterine glands - glycogen (main)

Question 9

Blastocyst (describe)

Answer 9

Hollow ball with Inner cell mass
Trophoblast - outer layer

Question 10

Early week 2

Answer 10

Trophoblast cells secrete enzymes that help it burrow into the endometrium — once fully attached it can begin to receive nutrients

Question 11

Later week 2

Answer 11

Inner cell mass becomes flattened disc and amniotic cavity develops
2 layers form - Epiblast and hypoblast

Question 12

Epiblast layer

Answer 12

Next to amniotic cavity
Gives rise to Ectoderm and mesoderm

Question 13

Hypoblast layer

Answer 13

Next to blastocyst cavity
Gives rise to endoderm
Gets thickkk = cranial region

Question 14

Purpose of the Lacunar networks

Answer 14

beginning of maternal-fetal circulation - develops within trophoblast - primary chorionic villi

Question 15

What occurs week three of embryotic development

Answer 15

Gastrulation - formation of the 3 germ layers
Neurulation - formation of the central nervous system
Cardiovascular system begins

Question 16

What are the three germ layers

Answer 16

Ectoderm, Endoderm, Mesoderm

Question 17

Ectoderm

Answer 17

Epidermis, hair, nails, teeth enamel, internal ear, retina
CAN, PNS

Question 18

Endoderm

Answer 18

Lining of respiratory and gastro tract
Epithelium of liver, pancreas, bladder

Question 19

Mesoderm

Answer 19

SKM, CV System, reproductive and excretory system

Question 20

Why would the pancreas be unaffected by maternal folate amounts

Answer 20

It does not develop until the 3rd trimester

Question 21

Later week 3

Answer 21

Folding of the neural tube
Development of paired somites from mesoderm, Coelom, link heart tubes, completion of chorionic villi

Question 22

Where would malformation resulting in spina bifida occur

Answer 22

the neural crest

Question 23

Purpose of the chorionic villi

Answer 23

Finger like projections on surface of placenta - play a key role in the exchange of nutrients, oxygen and waste products between mother and fetus

Question 24

Sequential gene

Answer 24

Week 4-8, major folding transverse and longitudinal - controlled by sequential gene

Question 25

Week 4 is

Answer 25

Neural tube ends close Heart now pumps blood Development of forebrain, limb buds, internal ears, eye lens

Question 26

Week 5-6 is

Answer 26

Rapid development of brain which requires DHA Head grows much greater than trunk

Question 27

Week 7-8 is

Answer 27

Limb development including bones GI tract formation (produces enzymes)

Question 28

Accumulation of body fat % at week 29 compared to 38. Why?

Answer 28

29 = 3.5% 38 = 16% No fat at 29 weeks, but most of the developmental structures are there

Question 29

What is the difference of focus from week 8 to week 9 from a nutritional perspective?

Answer 29

Week 8 - Quality Week 9 - Quality and quantity

Question 30

2 Parts to the placenta

Answer 30

Maternal - Endometrium layer - Lacunae structure Fetal party - Chorionic villus

Question 31

When and how does the Placental Villi complete

Answer 31

Week 3 Trophoblast vessels SA increase

Question 32

Differentiate between the umbilical vein and arteries

Answer 32

Vein: Allows for nutrient to be transferred to fetus Arteries: Brings O2 and nutrient depleted blood back to mom.

Question 33

What are the 3 functions of placenta

Answer 33

-Hormone secretion - HCG, estrogen, progesterone, placental lactogen -Metabolism -Transfer of nutrients and other substances

Question 34

Which hormone is the marker for pregnancy

Answer 34

Human chorionic gonadotropin hCG - Week 10 (depletes after)

Question 35

What does the placental metabolize

Answer 35

Glycogen, Cholesterol, FA

Question 36

Why does progesterone stay high when pregnancy is confirmed?

Answer 36

Prepares the uterus for pregnancy - prevents endothelial cells from sloughing off

Question 37

What are the 4 mechanisms of transfer for placental transfer

Answer 37

Simple diffusion - Water, FAs, Na, Cl Facilitated diffusion - glucose, iron, vit A, D Active transport - AA, water soluble vitamins Endocytosis - albumin, immunoglobulins

Question 38

Why would FFA be passive to the fetus

Answer 38

The baby needs lots of supply, Concentration gradient

Question 39

Describe the placental transfer of glucose

Answer 39

Facilitated diffusion, controlled by placental metabolism. Placenta uses 30-40% of glucose taken up from maternal circulation

Question 40

Describe the placental transfer of lipids

Answer 40

simple diffusion or facilitated. N-6 & n-3 are transferred through pregnancy - due to importance But lipids for fetal adipose tissue are transferred late in gestation

Question 41

Control and Transfer of AA

Answer 41

Transfer Active transport Controlled by Placenta SA, Placenta blood flow, placental permeability & conc gradient of protein