Prenatal Development and the Newborn Period Flashcards
1
Q
Epigenesis
A
Coined by Aristotle
The emergence of new structures and functions in the course of development
2
Q
Gametes (Germ cells)
A
- Sperm and egg
- Only contain half the genetic material each of all the other cells in the body
- Produced through meiosis
3
Q
Meiosis (cell division)
A
- Involves two cycles of cell division
- Each cycle involves the same four stages with some important differences
- Results in a germ cell containing 23 chromosomes
4
Q
Zygote
A
A fertilized egg
- Full complement of human genetic material
- 23 chromosomes from egg
- 23 chromosomes from sperm
5
Q
5 developmental processes that underlie the transformation of a zygote into an embryo and then a fetus:
A
- Cell division
- Cell migration
- Cell differentiation
- Apoptosis
- Hormones
6
Q
Embryo
A
Developing organism from the 3rd to 8th week of prenatal development
7
Q
Fetus
A
Developing organism from the 9th week to birth
8
Q
Cell division
A
- Mitosis
- Results in 2 identical cells
- Happens within 12 hours after conception
- The two cells continue to divide
- Over 38 weeks the zygote becomes a new born consisting of trillions of cells
9
Q
Cell migration
A
- Movement of newly formed cells away from their point or origin
10
Q
Cell differentiation
A
- Embryonic stem cells begin to specialize
11
Q
Apoptosis
A
- Genetically programmed cell death
12
Q
Influence of hormones
A
- Presence of androgens leads to the development of male genitalia
- Glucocorticoids help fetal tissues mature
13
Q
Prenatal development can be broken down into 3 stages:
A
- Germinal period
- Embryonic period
- Fetal period
14
Q
Germinal period
A
- First 2 weeks of development
- Zygote enters uterus
- Zygote becomes the blastocyst
- Blastocyst becomes fully embedded and this period ends
15
Q
Embryonic period
A
- Lasts from implantation to 8 weeks
- Cell differentiation
- Areas near the head develop first
