Week 15 Flashcards
Germinal period
The first two weeks after the sperm and egg unite
Gamete
A mature male or female cell used for reproduction
Haploid cell
A cell that contains only one set of a chromosome (egg and sperm)
Zygote
The product when a male and female gamete merge
Diploid
A cell that contains both sets of chromosomes, they are produced when the egg and sperm come together
Cleavage
The process that occurs during the germinal period where the zygote cell clones itself multiple times and is held together in a spherical shape
Morula
The product after a zygote undergoes cleavage multiple times
Epigenetic modification
Changes in cell inheritance that are not due to alterations in the sequence of DNA nucleotides. It allows some genes to be turned on and off, which leads to different proteins being expressed, thus causing different cellular properties and functions
Stem Cells
cells that have the same DNA as every other cell but has not undergone epigenetic modification
Androgens
In the absence of androgens, the fetus becomes female
Blastocyst
The process that a fertilized egg reaches after five to six days of fertilization
Inner cell mass
The cell mass inside the morula that eventually becomes the embryo
Trophoblast
The cells in the outerlayer that protects the inner cell mass and transmits nutrients
Embryo
An organism at its early stage of development
Embryonic period
begins after the implanation in the uterine wall and lasts about eight weeks
Amniotic Sac
Sac filled with liquid where the embryo resides
Placenta
Attached to the inside of the amniotic sac and transfers nutrients and acts as a filter and protective barrier for the organism
What are the three layers the embryo is separated in the Embryonic stage?
Endoderm, mesoderm, ectoderm,
Endoderm
The innermost layer that eventually becomes the digestive system, urinary tract and lungs
Mesoderm
The middle layer that becomes the muscles, bones, and circulatory system
Ectoderm
The outermost layer that becomes the skin, teeth, hair and CNS
Neurelation
occurs when the three cell layers differentiate and the newly formed tube (neural tube) starts to develop into the brain and spinal cord
Neurogenesis
the growth of new neurons (occurs 6-7 weeks after conception)
Neural migration
the process where neurons move, grow, and connect as the basic neural tube develops into a more mature brain