Unit 5: Early Human Dev. Flashcards
The zygote undergoes 4-5 mitotic divisions called _______ that will form the morula
Cleavage
When does the embryonic period take place?
The 3rd week of pregnancy to the 8th
What are the main 3 features of a blastocyst?
Blastocyst cavity, embryoblast (inner cell mass), and trophoblast (surrounding cells)
What is the term for the structure formed after the fusion of the sperm and egg during fertilization?
The structure formed after fertilization is called a zygote.
During pre-embryonic development, what is the term for the solid ball of cells formed after several divisions of the zygote?
The solid ball of 16-32 cells formed is called a morula.
The epiblast and hypoblast undergo mitosis to become which 2 formations?
Epiblast: forms the amnion and the 3 germ layers of the embryo
Hypoblast: forms the yolk sac
Fill in the blank: The inner cell mass of the blastocyst develops into the ________.
Amnion
What is the term for the outer layer of cells in the blastocyst that will contribute to the placenta?
The outer layer of cells in the blastocyst that will contribute to the placenta is called the trophoblast.
What is the term for the process by which the blastocyst implants into the uterine wall?
The process by which the blastocyst implants into the uterine wall is called implantation.
What membrane formed from trophoblast cells surrounds all embryonic membranes?
Chorion
What is the term for the outer layer of cells in the early embryo that will give rise to structures like the skin and nervous system?
Ectoderm
Which germ layer gives rise to structures like muscle, bone, and blood vessels?
Mesoderm
What is the name of the process by which cells differentiate into specialized cell types during embryonic development?
Cell differentiation
Describe the allantois
It is a projection off of the yolk sac which forms the umbilical cord and the urinary bladder
During which week of embryonic development does the heart begin to beat?
4th (embryonic period)
