embryology Flashcards
what is the name for a fertilised ovum?
zygote
what is a morula?
mass of cells
how many days in to a pregnancy is a morula formed?
4-6
what is a blastocyst?
hollow ball of cells with inner cell mass
when during pregnancy is a blastocyst formed?
6-10 days
how is the baby and mothers blood mixing prevented?
they are separated by a thin barrier known a the placenta
what is the placenta permeable to?
most molecules other than cells
when the embryonic inner cell mass forms 2 layers it is referred to?
bilaminar embryo
at how many days does the embryo become a bilaminar embryo?
10-12
what are the 2 layers of the bilarminar embryo called?
epiblast and hypoblast
what us the function of the epiblast in the bilaminar embryo?
gives rise to embryonic ectoderm
what us the function of the hypoblast in the bilaminar embryo?
participates in formation of endoderm and extra embryonic mesoderm
which twins are formed by splitting before fertilisation?
fraternal
which twins are formed from 1 egg?
identical
what is gastrulation of the embryo?
it forms an axis and 3 embryonic layers
what is the groove formed during gastrulation known as?
primitive streak
which 2 layers form the endoderm?
mesoderm and hypoblast
which cells form the mesoderm?
ectodermal cells
what is the name given to the early 3 layered embryo?
trilaminar embryo
what does the primitive streak develop into?
neural tube
when does the neural tube develop?
3-8 weeks
what is the name given to the development of organs from the 3 basic germ layers?
organogenesis
what is one of the 1st organs to form in an embryo?
CNS
what embryonic structure forms the CNS?
neural tube
what is the name of the 4th embryonic layer?
ectomesenchyme
which layer forms the ectomesenchyme?
ectoderm
which layer of the embryo is important for the development of the head?
ectomesenchyme
when in the development of an embryo does it start to take shape?
4 weeks
at which point in the development of a foetus does it have developed organs ?
9 weeks
when does an embryo become a foetus?
9 weeks
name the 3 cell types that all body cells come from
ectoderm (outer covering) mesoderm (middle) and endoderm (inner lining)
what structures does the ectoderm produce?
skin, mucous membrane, brain, spinal cord, TOOTH ENAMEL
what structures does the mesoderm produce?
connective tissue, muscle, blood vessels, kidneys, urinary system, reproductive system, serous membranes
what structures does the endoderm produce?
alimentary canal, respiratory system, urogenital organs
which stem cells are totipotent?
embryonic
which stem cells are pluripotent?
adult
what structures does the ectomesenchyme produce?
PNS, melanocytes, adrenal medulla, mesenchyme in head, DENTIN, PULP, PDL, JAW BONES
which period of pregnancy is of greatest sensitivity?
week 3-12
at which point of pregnancy do most developmental abnormalities occur?
week 3-12
which structure dives the ectoderm to proliferate to form the neural tube?
notochord
during development of the neural tube 2 clusters form above, these are known as?
neural crest
what tissue is the neural crest derived from?
ectoderm
what does the neural crest form?
ectomessenchyme
are stem cells from the 3 germ layers totipotent or pluripotent?
pluripotent
