Topic 1 - Prenatal Development Flashcards
(121 cards)
Typical prenatal development, which begins with fertilization and ends with birth, takes between _____
266 and 280 days (38 to 40 weeks).
Typical prenatal development, which begins with _____ and ends with _____, takes between 266 and 280 days (38 to 40 weeks).
fertilization
birth
three periods of prenatal development
Germinal
Embryonic
Fetal
period of prenatal development that takes place during the first two weeks after conception.
Germinal period
It includes the creation of the fertilized egg, called a ___
zygote
-specialization of cells to perform various tasks-starts to take place approximately one week after conception.
Differentiation
consists of an inner mass of cells that will eventually develop into the embryo
blastocyst
an outer layer of cells that later provides nutrition and support for the embryo.
trophoblast
the attachment of the zygote to the uterine wall, takes place about 11 to 15 days after conception.
Implantation
is the period of prenatal development that occurs from two to eight weeks after conception.
embryonic period
This period begins as the blastocyst attaches to the uterine wall.
embryonic period
The mass of cells is now called an _____
embryo
three layers of cells form in embryonic period
endoderm
Mesoderm
Ectoderm
is the inner layer of cells, which will develop into the digestive and respiratory systems.
endoderm
is the middle layer, which will become the circulatory system, bones, muscles, excretory system, and reproductive system.
mesoderm
is the outermost layer, which will become the nervous system and brain, sensory receptors (ears, nose, and eyes, for example), and skin parts (hair and nails, for example).
ectoderm
The endoderm primarily produces ____, the mesoderm primarily produces parts that surround the _____, and the ectoderm primarily produces ______.
internal body parts
internal areas
surface parts
As the embryo’s _____ form, life-support systems for the embryo develop rapidly.
3 layers
3 Lie support systems
Amnion
Umbilical cord (both of which develop from the fertilized egg, not the mother’s body)
Placenta
is a sac (bag or envelope) that contains a clear fluid in which the developing embryo floats.
amnion
provides an environment that is temperature and humidity controlled, as well as shockproof.
amniotic fluid
during this period, the rate of cell differentiation intensifies, support systems for cells form, and organs appear.
embryonic period
contains two arteries and one vein, and connects the baby to the placenta.
umbilical cord
consists of a disk-shaped group of tissues in which small blood vessels from the mother and the offspring intertwine but do not join.
placenta