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Flashcards in Conception And Fetal Development Deck (56):
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Conception

Union of eggs and sperm and marks the beginning of pregnancy.

1

Conception occurs in the...

Ampulla of the Fallopian tubes (not uterus)

2

Ovum comes from....

The grafting follicle at ovulation

3

Two protective layers of the ovum

Zona Pellucida
Corona Radiata

4

Zona Pellucida

Thick shapeless membrane that covers the ovum

5

Corona Radiata

Outer ring composed of elongated cells that are held together by hyaluronic acid

6

What chance of conception is there with a healthy cycle and good variables?

25%

7

Length of time it takes sperm to reach ovum and how long they are viable for

4-6 hours

72 hours

8

What is capacitation

When the sperm is exposed to the reproductive tract and it's protective coating on the acrosome (head) comes off. Enzymes escape and the enzymes are necessary for sperm to penetrate the egg

9

What is the Zona Reaction ?

When an egg is penetrated by one sperm, another will not be able to fertilize it and the egg will degenerate if it happens

10

What is a pronuclei?

When the nucleus of the spermatozoa and ovum become distinct bodies of chromatin (chromosomes)

11

What is the name of the structure with 46 chromosomes

Zygote

12

What are the three main events of the pre embryonic period?

Divisions of cells
Implantation
Development of fetal membranes

13

How many times does the zygote divide?

Until 64 cells are produced

14

At what number cell stage does the zygote enter the uterus?

16 cells stage (morula)

15

What is a morula?

A 16 cell stage surrounded by a Zona Pellucida

16

What has to happen before a zygote embeds?

Divide into a blastocyst

17

What happens during implantation?

The Zona Pellucida degenerates
Structural changes occur
Fluid in the center pushes cells to the outside border
The inner cell mass (blastocyst) becomes the embryo and embryonic membranes

18

What is the outer cell mass of the embryo called and what is its principle function?

Trophoblast- eventually become the chorion
To secure food for the embryo and embed the ovum

19

Where is the ovum usually implanted

Upper part of uterine wall

20

What are chronic villi

Finger like projections that develop out of trophoblasts into the endometrium

21

Why are chronic villi important

They contain blood vessels that get O2 and nutrients from moms blood and dispose of waste
They also secrete Hgc hormone

22

What is the corpus luteum

Secretes progesterone until the placenta is formed

23

What is HGC?

Human chorionic gonadatropin
A hormone that maintains progesterone production by the corpus luteum

24

What does progesterone do?

Supports to product of conception- holds off the period

25

What does the endometrium change to once fertilization and implantation takes place?

Decidua

26

What is a decidua?

A structure that loses its structure after 40 weeks... In this case a gestation term instead of monthly (uterus)

27

What is a decidua basalis?

The part directly under the embedded ovum that forms the placenta

28

What is the decidua calsularis?

The portion that overlies the ovum and separates it from the rest of the uterine cavity

29

What is the decidua Vera?

The remaining portion that is not in immediate contact with the fertilized ovum

30

What is the chorion?

The outermost embryonic membrane that is furthest from the embryo and closest to the mother. It covers the fetal side of the placenta

31

What is the chorion developed from?

The trophoblast

32

What is the amnion?

It is generated from fluid filled space around the embryo called the amniotic cavity. It's lined with a glistening smooth membrane. It encases the fetus with fluid and is closest to the fetus

33

Characteristics of Amniotic fluid

Fetus floats in it, maintains temperature, provides cushion against injury, clear yellow to straw, fetus drinks and voids into it

34

What does amniotic fluid contain?

Lanugo, albumin, urea, epithelial cells, vernix

35

What is lanugo

Fetal hair

36

What is vernix

Cheese like substance that coats baby

37

When does the heart start beating

10 days

38

What is the shiny vs dirty side of the placenta

Shiny side- fetal side
Dirty side- mothers side

39

When is the embryonic period and when are organs fully functionable?

3-8 weeks, at 8 weeks organs are formed and functioning

40

What is organogenesis

Organ system development

41

What is the function of the placenta

To connect the fetus to the uterine wall via umbilical cord to provide nutrients, respiration, and excretory functions

42

When is the placenta functional and what stood in its place until it was developed?

12 weeks, chorion

43

What does the placenta act as

Lungs, kidneys, endocrine, digestive system, liver and immune system

44

What viruses can cross to baby?

Hep b and HIV

45

Characteristics of placenta

Maternal side is rough, bloody, 22 irregularly shaped lobes, round, 8-10 inches
Fetal side is smooth and shiny

46

What hormones does the placenta produce

Progesterone, estrogen, relaxin, hpl (human placental lactogen for breast milk production)

47

What are the germ layers?

Ectoderm- outer
Mesoderm- middle
Endoderm- inner

48

Function and structure of umbilical cord

Connects fetus to placenta to mother
Has 2 arteries and 1 vein
Arteries carry deoxygenated blood
Vein carries oxygenated blood
18-22 inches long

49

What is whartons jelly

Jelly like substance in umbilical cord that is 90% water

50

What are the 2 blood circulations

Bypasses fetal lung
Oxygenation occurs in placenta

51

What does blood bypass while going through the umbilical vein?

Ductus venosus then to inferior vena cava

52

What does the foremen ovale do

Shunts blood to body

53

What must the foremen ovale do once born?

Snap shut because it is critical to respirations

54

What do the ductus arteriosus and ductus venosus do once born?

Atrophy and become ligaments

55

When does atrial-septal defect result?

When the foremen ovale doesn't snap shut