Embryology Flashcards
Define the stages of embryology
zygote is formed and divides to form a blastocyst. moves through uterine tube to reach uterine cavity. implantation occurs in the uterine endometrial layer and placenta begins to develop
Describe the formation of the gametes and fertilisation
Describe the formation of the blastocyst and its implantation into the uterine wall
During fertilization, the sperm and egg unite in one of the fallopian tubes to form a zygote. Then the zygote travels down the fallopian tube, where it becomes a morula. Once it reaches the uterus, the morula becomes a blastocyst. The blastocyst then burrows into the uterine lining — a process called implantation.
Outline the formation of the placenta, placental villi and the general functions of the
placenta
villi for vascularisation of the placenta.- give foetal brain nutrition
Describe the formation of the bilaminar disc
cells of inner mass flatten and form a 2 layered bilaminar disc and two cavities begin to form called amniotic cavity and yolk sac
Describe the formation of the trilaminar disc
function of blastocyst cavity
to get nutrients to the cell
what are the outer layer of the cells called
trophoblasts
what happens to the cells that form the outer cell mass known as trophoblast
divide to form 2 layers and forms a chorion which develops finger like processes called chorionic villi
function of chorion
involved in inplantation, forms part of the placenta in due course and secretes human chorionic gonadotropin
main functions of placenta
foetal nutrition, transport of waste and gases, immunity
gastrulation
formation of germ layers
neurulation
formation of neural tube
what is the primitive streak
formed in the midline of the epiblast by the dipping in of cells (invagination). Once primitive streak forms the axis of the embryo is formed
describe gastrulation
epiblasts cells migrate to lie in-between epiblast and hypoblast layers. cells displace hypoblast layers and forms 3 germ layers
1. ectoderm
2. mesoderm
3. endoderm
trilaminar disc is now formed