How tissues are made from cells Flashcards
what is a zygote
a fertilised egg
what formes at the 32 cell stage
the morula is formed
where do cell to cell junctions form?
in the morula
what can we no longer see at the 32 cell stage
individual cells
is the hypoblast primitive endoderm or primitive ectoderm
primitive endoderm
is the epiblast primitive endoderm or primitive ectoderm
primitive ectoderm
what does the inner cell mass split into
the epiblast cells and hypoblast
how is the mesoderm formed
when cells from the epiblast migrate down to form the mesoderm
how is the primitive streak formed
The primitive streak descends from a group of cells that form the primitive node.
what makes up the amnion
Ectoderm + Mesoderm
what makes up the chorion
Trophoblast + Mesoderm
what makes up the yolk sac
Endoderm + Mesoderm
what is the primitive streak
a region of forming mesoderm in
trilaminar disc stage.
how does the tube of the primitive gut form
The trilaminar disc folds as it grows and develops so that the ectoderm completely
surrounds the body and the endoderm becomes the tube of the primitive gut
the ectoderm and endoderm are epitheal
true or false
true
Mesoderm doesnt have the looser structure of mesenchyme.
true or false
false. Mesoderm has the looser structure of mesenchyme.
4 types of cells or tissues
Epithelial
Muscle
Nervous tissue
Connective Tissue
what are somatic cells
the cells of the body
what are germ cells and what is special about them?
Germ cells are the gametes – eggs and sperm
Germ cells generally cannot be changed by the body that bears them
what is Hyaluronidase for
to digest through cumulus
what are morula
– cell:cell junctions form, can no longer see individual cells
how long is the cleavage cycle
24H
concept of empbryo development
genetic material combined increase cell number geneone activated cell to cell junction begin to form then differentiation prtotein synthasesis Na/K atpase true growth and prep for implantation
what is a blastocyst
contains cavity
120-168h post fertilisation
describe the bilaminar disc
Cells of the ICM split into two types – Epiblast cells and hypoblast cells. Epiblast cells are primitive ectoderm whereas hypoblast are primitive endoderm. This stage is known as the bilaminar disc
desribe the folding
Blastocyst with epiblast and hypoblast
Mesoderm forms in between
Hypoblast begins to surround the inner face of the trophoblast and meets at the base
Mesoderm grows between hypoblast and trophoblast and between epiblast and trophoblast –cavities form
Cell layers divisible into embryonic ectoderm, mesoderm and endoderm, amniotic ectoderm/mesoderm and yolk sac
Trilaminar embryonic disc curls up; outer ectoderm surrounded by amniotic cavity, itself surrounding mesoderm which surrounds endoderm
