Embryonic & Fetal Development Flashcards
Interval of prenatal development
From conception to birth
Interval of infancy and toddlerhood
From birth through 2 years
Interval of early childhood
3 to 5 years
Interval of middle childhood
6 to 11 years
Interval of adolescence
12 to 18 years
What is meant by gestation
Period of time required for full development of a fetus in utero
According to WHO, anyone under the age of ________ is a child
18
Example question :
When we say “28 weeks gestation” , what do we mean by that?
28 weeks in the womb
Or 28 weeks after conception
The term “gestare” means what
To carry or To bear
The first 2 weeks of prenatal development are referred to as the ___________________.
Pre-embryonic stage
When is the pre-embryonic stage ?
First 2 weeks of prenatal development
A developing human during weeks 3-8 is referred to as an ____________.
Embryo
A developing human from the 9th week of gestation until birth is referred to as a ____________.
Fetus
When is a developing human referred to as an embryo ?
Weeks 3-8 gestation
When is a developing human referred to as a fetus?
Week 9 gestation until birth
Embryonic stages of development are characterized by what
- cell division
- migration
- differentiation
True or false
By the end of the embryonic period, all the organ systems are structured in basic form.
True
Describe the function of the organs by the end of the embryonic period?
Either nonfunctional or semi-functional
Describe the stages of pre-embryonic development and
Unfertilized oocyte
Fertilized oocyte
Two-cell stage
Four-cell stage
Eight-cell stage
Morula (16 cells)
Blastocyst (70-100 cells)
After that we have implantation:
- zona pellucida sheds
- blastocyst implants in endometrium of uterus
A morula contains how many cells
16 cells
A blastocyst contains how many cells
+ describe its structure
70-100 cells
It is a sphere of cells surrounding a fluid-filled cavity called blastocoel. The outer layer consists of trophoblast cells that will form the placenta. The inner cell mass (embryoblast) will form the fetus eventually .
When does the process of implantation begin ? And what does it signal ?
Begins at the END of the 1st week.
It signals the END of the pre-embryonic stage of development
What happens during implantation ?
- The blastocyst adheres to the endometrium
THEN - the trophoblast secretes hCG
What is hCG and what is its role?
hCG is Human Chorionic Gonadotropin
It is a hormone that directs the corpus luteum to survive, enlarge, and continue producing progesterone and estrogen to suppress menses (menstruation/period)