Lecture 2 Flashcards
What becomes the embryo?
the epiblast
What happens during the fetal period?
growth and maturation of existing organs
What is a morula?
contains 16 cells
Does the heart pump blood right after organogenesis?
No
What are somites?
block-like structures of mesoderm
What does the caudal neural tube become?
the spinal cord
What is the cytotrophoblast?
individual cells that remain from the trophoblast
What is apoptosis?
programmed cell death
What is the mesoderm?
a layer of cells that fills in the space between the endoderm and ectoderm
What is the pre-embryonic period?
weeks 1-2
What does the inner cell mass of a blastocyst become?
embryo
How is the neural groove formed?
tissues on the sides of the neural plate fold upward into neural folds
What is the endoderm?
A sheet/layer of cells that displaces the hypoblast
What is the syncytiotrophoblast?
Breaks down part of the trophoblast that attaches to the uterine wall
When does differentiation of cell types begin to happen?
gastrulation
What is the primitive streak?
an indentation along the dorsal surface of the epiblast that allows cells to descend through it to create two new layer of cells
What is the prenatal period?
first 38 weeks of human development
What is body folding?
the embryo begins to acquire a cylindrical shape essentially creating a tube called the primitive gut which is lined by the endoderm.
What period does body folding happen
embryonic
What is the fetal period?
weeks 9-38
Does the heart beat after organogenesis?
Yes
What does the trophoblast become?
chorionic membrane and the fetal portion of the placenta
What is cleavage?
When a zygote undergoes five or six mitotic cell divisions
What happens to the size/mass of the zygote as it goes through cleavage?
Stays the same
How is the neural tube formed?
the neural folds converge
What is the blastocoel?
fluid filled area in the blastocyst
What is organogenesis?
The rudimentary structures of all tissues and organs are established
What is an oocyte?
a female egg
What is a zygote?
a fertilized egg, single cell
What are the primary germ layers?
endoderm, mesoderm, ectoderm
What is neurulation?
parts of the central nervous system develop from the ectoderm
Where does neurulation happen?
the mesoderm
What is the bilaminar disc?
comprised of the epiblast and hypoblast
What is the chorion?
cell membrane that surrounds the embryo and fetus
What period does gastrulation occur?
embryonic
How is the brain formed?
the cephalic neural tube dilates
How is the neural plate formed?
ectoderm cells thicken
What is the embryonic period?
weeks 3-8
What period do lim buds form?
embryonic
What is the ectoderm?
cells of the epiblast that have not migrated through the primitive streak. makes ups the outside layer
What period does organogenesis occur?
embryonic
What period does the primitive streak form?
embryonic
What does the mesoderm become?
skeleton, muscles, connective tissue, hear, blood vessels, kidneys
What does the endoderm become?
gastrointestinal tract, respiratory tract, urinary tract
When does the blastocyst come in contact with the uterine wall and adheres to it?
the end of the first week
What is a blastocyst?
next step after morula. contains around 100 cells. starts to an inner cell mass and a trophoblast
What is gastrulation?
results win the formation of the primary germ layers
What does the neural tube become?
the brain and spinal cord
What does the ectoderm become?
nervous system, sensory organs, epidermis, hair, nails
What do somites differentiate into?
axial skeleton, skeletal muscle, dermis
What period does neurulation occur?
embryonic
Where do the epiblast and hypoblast come from?
the original inner cell mass
