DAT Embryology Cheat SHeet Flashcards
The female gamete is the..
egg
outermost layer of egg
Corona Radiata
male gamete is the
sperm
Biochemical process initiated by secretions in the uterus and fallopian
tubes to make sperm more active in female reproductive tract
capacitation
where does sperm swim thru for first step of fertilization
corona radiata
once the sperm swims thru corona radiata, where does it arrive
zona pellucida (aka vitelline membrane)
after sperm arriving in zone pellucida, what happens
Acrosome reaction is triggered; hydrolytic enzymes digest
through zona pellucida
after acrosome rxn what happens,
Sperm enters perivitelline space and fuses with egg plasma
membrane
after sperm fuses with egg plasma membrane, what happens
The haploid nucleus of sperm enters the egg
final step of fertilization
2 haploid nuclei fuse to form the diploid zygote (2n)
Occurs instantaneously when sperm fuses with plasma membrane
fast block
for fast block, what channels open and close
sodium channels along membrane open, causes influx in Na
Depolarization of egg membrane changes… fast block
charge of membrane,
preventing other sperm from binding for a short duration of time
Longer lasting block occurring after fast block
slow block
Depolarization of egg causes… what for slow boock
Ca2+ release from endoplasmic reticulum into cytoplasm
WHAT fuse with membrane and release their contents outward into perivitelline space (slow block)
cortical granuls
does membrane shrink or enlarge during slow block
enlarge
once membrane enlarges, what happens (slow block)
zona pellucida (now known as the fertilization membrane/envelope)
detaches and hardens, preventing future sperm from being able to bind
After slow block, a second…
meiotic division of the egg is completed
With each round of mitosis, early embryo goes through
rapid cell division
does amount of cytoplasm change with each round of mitosis for early embryo
no
New cells formed directly above previous cells
radial
New cells formed at angle to previous cells
spiral
Cell decides its fate (what type of cell to
become) early in development
Determinate (Mosaic):
Separated blastomere and the remaining embryo can’t form…. (determinate)
a complete embryo
Removing blastomere would remove…
an irreplaceable and critical
piece of organism
Fate of cell is determined later in
development
Indeterminate (Regulative):
If blastomere is removed, it and the remaining embryo can.. (indeterminate)
form a
complete organism à resulting in 2 complete normal organisms
protostome direction of cleavage
spiral
dueterostome direction of cleavage
radial
protostome type of cleavage
determinate
dueterostome type of cleavage
indeterminate
coelom formation protostome
Schizocoelus
coelom formation dueterostome
Enterocoelus
cell has decided what genes will be
expressed and which will be repressed
determined
When we can look under the microscope and see a physical change
in the cell expressing those genes
differentiation
All fertilized zygotes will undergo a series of rapid cell divisions called
cleavage
(increasing cell count without increasing
cell size)
cleavage
when will fertilized zygotes undergo cleavage
while traveling down the fallopian tubes for implantation
fertilized zygote goes to…
morula
morula ->
blastula
blastula - >
gastrula
gastrula ->
neurula
(solid ball of cells)
morula
(hollow sphere of cells)
blastula
The morula (solid ball of cells) becomes a blastula (hollow sphere of cells)
blastulation
human embryos in blastulation are known as
blastocysts
The blastula becomes the gastrula as cells begin to invaginate with…
a blastopore
what does blastopore go on to become
mouth or anus
The blastula becomes the gastrula as cells begin to invaginate with a blastopore that will go on to become the mouth
(protostome) or anus (deuterostome)
gastrulation
During gastrulation, different parts of the embryo begin to…
interact with one another for the first time
3 germ layers
ectoderm, mesoderm, endoderm
Even the most primitive organisms form WHAT during gastrulation
gut tube
a cell can influence the development of nearby cells how
induction
stimulates overlying
ectoderm to thicken via induction
notocord
go on to form parts of the intervertebral discs & spinal vertebrae)
notocord
what does neural plate do in second step of neuralation
flods
what does neural plate eventually form
neural tube
The neural tube will go on to form the
brain and spinal cord
4 key features that all chordates have during development
notochord, post anal tail, dorsal hollow nerve cord, pharyngeal gill slits
Epidermis layer
(skin/hair) germ layer
ectoderm
Adrenal
Medulla
ectoderm
Jaw + teeth
ectoderm
Sensory
system
ectoderm
Nervous
system
ectoderm
(GI & respiratory
tract,
endoderm
excretory system,
endoderm
reproductive tract)
endoderm
Thyroid, parathyroid, and thymus
endoderm
Liver
endoderm
Circulatory
system
mesoderm
Lymphatic
system
mesoderm
Skeletal system
mesoderm
Muscular
system
mesodrm
Adrenal
cortex
mesoderm
notocord
mesoderm
amphibian… Embryo rotates 30° on its axis to form an area called
grey crescent
Gray crescent formed where
(formed exactly opposite of the sperm’s point of entry)
develop specialized
membranes outside embryo to help nourish and support it
amniotes
lack the amnion and
extraembryonic layers à lay their eggs in water
non amniotes
2 genetically identical embryos
monozygotic
regular
siblings just born at the same time
dizygotic
