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JohBio 32: Vertebrate Embryology
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Bio 32: Vertebrate Embryology
Laboratory Guide/Notes
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Vertebrate Embryology Lab Notes, Page 2 John Tran 2009
Frog Slides: Up to Gastrulation
Term
Animal Pole
Check Greek/Latin Origin
Box
Roots
.
Zygote
portion w/o
yolk
Vegetal Pole
.
Zygote
portion w/
yolk
Grey
Crescent
.
Meroblastic
Cleavage
.
Mer =
Part
Zygote
portion
opposite of
sperm entry
Mitosis
Holoblastic
Cleavage
.
Holo =
Whole
Mitosis
Morula
.
Morus =
Mulberry!!!
Yum :]
Zygote
Blastula
.
Blastos =
Sprout
Morula
Blastomere
.
Blastos =
Sprout
Mer = Part
Blastula
Definition
Establishes
Cranial/Caudal/Dorsal/Ventral
Axis. Will be future cranial
area
Identify
Pole contains the smaller
micromeres and has a
darker pigmented edge at
the top. Opposite the
vegetal pole
Establishes
Pole contains the larger
Cranial/Caudal/Dorsal/Ventral yolky macromeres and
Axis. Will be future caudal
cells are less compacted.
area. Cells are extremely
Opposite the animal pole
yolky at vegetal pole
Establishes
Look for a “wedge” that
Cranial/Caudal/Dorsal/Ventral has a grayish color. It’s
Axis. Will be future Dorsal
where the Animal Pole
area.
meets the Vegetal Pole
When mitotic cell division
You can point to a
results in unfinished cell
cleavage furrow for a
division. This is common for avian zygote…I liked to
telolecithal eggs like reptiles
point to cleavage furrows
and birds because the yolk is
in the blastodisc
so large, cleavage does not
separate the yolk
When mitotic cell division
You can point to a
results in complete cell
cleavage furrow for an
division. This is very
amphibian or fish
common for isolecithal or
zygote…
mesolecithal eggs because the
yolk does not hinder cell
division
After the union of egg and
Compact, solid, “Ball” of
sperm, a series of rapid
cells… It should not have
mitotic divisions results in
an internal cavity yet...
hyperplasia and a compact,
MUST be solid
solid, “ball” of cells
Cavity of the solid Morula
Look for the blastocoel.
ball called a blastocoel. This
If the structure looks like
is the precursor structure to
a “hollow ball” then it is a
the gastrulating trilaminar
blastula
embryonic structure
General term to describe any
Easy! Point to any cell in
cell within a blastula
the blastula, large or
small!!! Yay
______________________________________________________________________________
Vertebrate Embryology Lab Notes, Page 3 John Tran 2009
Macromere
.
Macro =
Large
Mer = Part
Blastula
Micromere
.
Micro =
Small
Mer = Part
Blastula
Blastopore
.
Blastos =
Sprout
Pore =
Passage
Blastula
Yolk Plug
.
Archenteron .
Dorsal
Blastopore/
Spemann’s
Organizer
Ectoderm
.
Mesoderm
.
Endoderm
.
Notochord
.
.
.
.
.
.
.
.
Blastula
Arc =
Ancient
Blastos =
Sprout
Pore =
Passage
Ecto =
Outside
Meso =
Middle
Endo =
Inside
Noto =
Back
Describes only the larger cells
of the blastula. Develops
structures related to vegetal
pole and contains nutritious
yolk
Describes only the smaller
cells of the blastula. Develops
structures related to animal
pole
Results from the invagination/
involution/ epiboly of
blastula. Future anus for
amphibian zygotes
Full of endodermal, yolk-rich
cells that fills up the hole
created by the blastopore.
Blastula.
Ancient Gut. Results from the
invagination/involution of
gastrulation. Roof of
archenteron (dorsal region) is
mesoderm while the floor
(ventral region) is endoderm.
Major step for gastrula and
the trilaminar structures
Blastula
Important Organizer!
Responsible for primary
induction AKA
Dorsal/Ventral Axis
Blastula
Outermost layer of trilaminar
structure
Blastula
Middle layer of trilaminar
Archenteron structure
Blastula
Innermost layer of trilaminar
Archenteron structure
Mesoderm
Future vertebral column. Will
be found in majority of the
sections you look at
Easy! Point to large cells
near vegetal pole
Easy! Point to small cells
near the animal pole
Looks like a dent in the
spherical mass of cells.
Near the yolk plug. On
cross sections it disrupts
the perfect spherical
shape of the blastula
Looks like a stopper or
“plug” within the
blastapore’s dent
Another cavity in the
blastula and is located
close to the animal pole.
Do not confuse with the
blastocoel. When you see
this long tube in your
embryo you know it is
gastrulating!
Go back to the blastopore
and point to a dorsal “lip”
AKA part of blastopore
located dorsally
Point to outer most layer
of cells of blastula
Point to roof of
archenteron
Point to floor of
archenteron
Small dark dense circle
located near dorsal
portions of sections
______________________________________________________________________________
Vertebrate Embryology Lab Notes, Page 4 John Tran 2009
Frog Slides: More advanced development
Frog Development is straightforward and follows a straight cranial-caudal lay out. There
is no flexure or torsion.
Term
Check Greek/Latin Origin
Box
Roots
.
Neural
Ectoderm
Definition
Identify
Early sign that a neural tube is
forming. A starting feature of
neurulation
Primitive
Ridge
.
Neural
Ectoderm
Early sign that a neural tube is
forming. A starting feature of
neurulation
Neural
Groove
.
Neuro =
Brain
Neural
Ectoderm
This is the future lumen of the
neural tube. Is a more
developed version of the
primitive groove.
Neural Folds
.
Neuro =
Brain
Neural
Ectoderm
This is the structure that
allows the neural grove to
become the neural tube. Is a
more developed version of the
primitive ridges
Spinal Cord/
Neural Tube
.
Neuro =
Brain
Neural
Ectoderm
This becomes part of the
central nervous system.
Sensory info from PNS
collected, integrated, and sent
to spinal cord to send to the
brain
Segmental
Plate/
Paraxial
Mesoderm
.
Mesoderm
Mesoderm that will turn into
the somites (future
musculature and skeletal
system of organism)
Slight depression or
“valley” like feature in
the neural ectoderm.
Point towards caudal end
because the tail region is
less developed and more
“primitive”
Slight raised ridges that
will later grow into more
pronounced neural folds.
Point towards caudal end
because the tail region is
less developed and more
“primitive”
More pronounced
depression or “valley”
like feature in the neural
ectoderm. Point towards
cranial end because this
region is more developed.
Neural groove may have
fully closed over to
become neural tube.
More pronounced raised
ridges running parallel to
the neural grove. Point
towards the cranial end
because the head region
is more developed.
Almost same structure as
the neural groove except
that the neural folds fuse
and forms a tube. Point
towards the more cranial
regions because the head
region is more developed.
Find the notochord. Then
find aggregations of
mesodermal cells lateral
to the notochord.
Primitive
Groove
______________________________________________________________________________
Vertebrate Embryology Lab Notes, Page 5 John Tran 2009
Somites
.
Soma =
Body
Mesoderm
Notochord
.
Noto =
Back
Chorda
Mesoderm
Optic Cup
.
Opt = Eye
Ectoderm
Sensory
Retina
.
Optic Cup
Future neural cells like
bipolar, horizontal, or
ganglion, rods, and cones of
the photosensitive region of
the retina
Pigmented
Retina
.
Optic Cup
Future pigmented region of
the retina
Auditory
Vesicle
.
Ectoderm
Future ear structure
Endocardial
Tubes/
Cardiac
Mesoderm
Endocardial
Tubes/
cardiac
Mesoderm
Also called bulbis cordis
This primordial structure will
eventually fuse with the
ventricle to help pump blood
The portion of heart that
pumps the blood to the rest of
the body. Largest chamber of
the heart
Endocardial
Tubes/
Cardiac
Mesoderm
The portion of heart that holds
blood before it is pumped into
ventricle. Smaller than
ventricle and muscle walls are
thinner
Small dark dense circle
located near dorsal
portions of sections
Huge lateral circular
bulges coming out of the
prosencephalon. Hard to
miss
Look near
prosensephalon for the
bulging optic cups. Point
to the thicker, more
lateral membrane of the
optic cup
Look near
prosensephalon for the
bulging optic cups. Point
to the thinner, more
medial membrane of the
optic cup
Located near the
rhombencephalon. Look
like circular dark disks
on the head
One of the more cranial
structures out of the heart
structures. Small-ish and
circular
In frogs, directly follows
conotruncus in cranialcaudal fashion. Largest
chamber of the heart with
very thick muscle walls
In frogs, directly follows
ventricle in cranial-caudal
fashion. Smaller
chamber of the heart with
thinner muscle walls.
Mesoderm
A PAIR of arteries that lie
Look for two arteries in
Aud =
Hearing
Conotruncus .
Ventricle
.
Vent = Body
Atrium
.
Dorsal
.
An atrium in
greco roman
architecture
is a large
open space
in a building
Dors = Back
Future musculature and
skeletal system of organism.
Subdivided into dermatome
(future dermis), myotome
(future muscle), sclerotome
(future skeleton)
Future vertebral column. Will
be found in majority of the
sections you look at
Future Retinal portions of the
eye. Occur as evaginations
from the prosencephalon
They look like circular or
oval shaped masses of
cells lateral to the
notochord. One of the
easiest structures to spot
______________________________________________________________________________
Vertebrate Embryology Lab Notes, Page 6 John Tran 2009
Aorta
close to dorsal side. Later
forms the descending aorta
and contributes to the aortic
arch system.
The interim kidney. Sort of
functional but not
efficient…especially for
humans
mesonephric
Kidney
.
Nephr =
Kidney
Mesoderm
Stomodeum
.
Stom =
Mouth
Future oral cavity
Foregut
.
For = Front
Ectoderm
and
Endoderm
contribution
Endoderm
Midgut
.
Mid =
Middle
Endoderm
Hindgut
.
Hind =
Behind
Endoderm
Middle portion of the
intestinal tract. Will be the
future site jejunum, ileum,
and first portion of large
intestine.
The more caudal region of the
intestinal tract. Will be future
site of large intestine
Proctodeum
.
Proct =
Anus
Endoderm
.
.
The more cranial region of the
intestinal tract. Will be future
site of esophagus, trachea,
lungs, stomach, and
duodenum
Future Anus
the dorsolateral region of
sections. They will
typically be behind the
pharynx/ gut
Found alongside the
descending aorta/dorsal
aorta. Look like large,
spongey, dark, circular
structures.
Best seen from a sagittal
section. Obviously, look
towards the cranial
sections
Look for small, dark,
circular structure that is
ventral to the notochord.
Choose cranial range
slides. Stomach is easy to
spot because the lumen is
usually larger
Look for small, dark,
circular structure that is
ventral to the notochord.
Choose mid range slides.
Look for small, dark,
circular structure that is
ventral to the notochord.
Choose caudal range
slides
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Vertebrate Embryology Lab Notes, Page 7 John Tran 2009
Gametes: Testicles
Term
Check Greek/Latin Origin
Definition
Box
Roots
Sperma =
Spermatogonia Cell that will begin the
Spermatagonia .
Seed
A which came meiotic cycle of gametes.
B
from PGC
Primary
Spermatocyte
.
Sperma =
Seed
Cyt = Cell
Spermatogonia (2N, 4C) Cell that
B
undergoes meiosis I
Secondary
Spermatocyte
.
Sperma =
Seed
Cyt = Cell
Primary
Spermatocyte
(N, 2C) Cell that
undergoes meiosis II
Early
Spermatid
.
Sperma =
Seed
Id = Shape
Secondary
Spermatocyte
(N,C) that begins
spermiogenesis to form
mature sperm.
Sperm
.
Sperma =
Seed
Early
Spermatid
(N,C) cell that will flow
into lumen. Mature. Has
three distinct structures 1)
Acrosome cap 2) Flagella
3) small body
Seminiferous
.
Intermediate
Extensive tubules that will
Identify
Usually located at the
basal portion of the
seminiferous tubules.
They are often larger in
size as well. Since
these B cells undergo
Meiosis they are
considered “Dark”
because of all the
replicating DNA
Usually located toward
the basal portion of the
seminiferous tubules.
They are large in size
and have a dark center
(all the replicated
chromosomes can be
seen!) Odds are, most
of the large cells you
spot in the testis are
primary.
Start moving to the
luminal region of the
seminiferous tubules
…This is one of the
hardest ones to spot
Usually located toward
the luminal portion of
the seminiferous
tubule. They are very
small and ROUND
(they don’t look like
mature sperm yet)
Usually located at the
luminal portion of the
seminiferous tubule.
They are small and
ARROW shaped.
Look for the flagella!
You can see the flagella
as hair like projections
in the lumen
Just point to a circular
______________________________________________________________________________
Vertebrate Embryology Lab Notes, Page 8 John Tran 2009
Mesoderm
AKA
Urogential
Mesoderm
Tubule
Basal Portion
of Tubule
.
Bas =
Bottom
Luminal
Portion of
Tubule
.
Lumen
means an
open center
of a tube
Interstitial
Cell/ Leydig
Cell
.
Leydig =
Scientist
name
Sertoli Cell
.
Sertoli =
Scientist
.
.
Intermediate
Mesoderm
AKA
Urogential
Mesoderm
Intermediate
Mesoderm
AKA
Urogential
Mesoderm
be sectioned off into
lobules in the testicles.
These tubules are where
sperm is made and
temporarily housed
This is the outer rim of the
seminiferous tubules.
Gametes early in their
development start here.
Remember, development
occurs from the basal to
luminal direction
This is the inner lumen of
the seminiferous tubules.
Gametes later in their
development end here.
Remember, development
occurs from the basal to
luminal direction
Cells activated by ICSH
and are important for
endocrine functions like
testosterone
Cells activated by FSH and
are commonly called
“Nurse Cells.” They
release ABP, AMH, and
are also phagocytic (they
eat cytoplasm shed from
the spermatid)
lumen. They are
everywhere!
Depending on how
testis were cut, tubules
might appear circular,
oval, or really awkward
shape
Point to the outer rim
of the seminiferous
tubule
Point towards the inner
rim/lumen of the
seminiferous tubule
These are squashed
looking cells that are
mostly seen in between
the seminiferous
tubules.
These cells are usually
massive looking. They
are oddly shaped
because there are
developing sperm
attached to the sertoli.
I look for a distinct
small, dark, nucleolus
because sertoli cells are
in interphase. Also
located toward the
basal layer. Also look
for oval nucleus…these
are really hard to find :[
______________________________________________________________________________
Vertebrate Embryology Lab Notes, Page 9 John Tran 2009
Gametes: Ovary
Term
Primordial
Follicle
Check Greek/Latin Origin
Box
Roots
.
Follicle =
Intermediate
Contains
Mesoderm
cavity
AKA
Urogential
Mesoderm
Primary
Follicle
.
Follicle =
Contains
cavity
Primordial
Follicle
Secondary
Follicle/
Mature
Follicle/
Graafian
Follicle
.
Follicle =
Contains
cavity
Primary
Follicle
Cumulus
Oophorous
.
Col =
Column
Oo = Egg
Follicular
Cells
Corona
Radiata
.
Coron =
Crown
Radia =
Follicular
Cells
Definition
Females start with these basic
structures for housing their
gametes. It is a small ring of
follicular cells that surround
the primary oocyte arrested at
prophase I (2N, 4C)
Identify
There should be plenty of
these to find. Look for
small circle like
structures. There is one
simple ring of follicular
cells around a larger
central primary oocyte .
They are always clustered
at the basal region.
Once FSH start during sexual Look for a structure
maturation, select number of
similar to the primordial
primordial follicles are chosen follicle. However, two
to finish meiosis I and
differences exist. 1) the
development.
Ovum is larger 2) There
are concentric rings of
follicular cells
surrounding the ovum. I
usually see between 2-5
rings…it has developed
to make the theca
interna/externa yet
These follicles will rupture
Look for a large circular
sending the ovum directly into structures. There are
the oviducts for transport to
usually not that many in
the uterus.
an ovary. Look for the
following features 1)
Large antrum 2) Cumulus
oophorous 3) Close to the
basal edge of the
ovary…sometimes you
can see the theca
interna/externa pretty
well defined as well
This is a support stalk that
This structure is easiest to
suspends the ovum in the
find in the Graafian
center of the fluid filled
Follicles. You can
antrum. It’s made of
usually see this column
granulosa cells
like structure that lifts the
ovum into the center of
the antrum.
Made up of a follicular cells
Look closely at a
that form a barrier around the secondary oocyte. Notice
ovum. Their purpose is to
that there is a ring of cells
______________________________________________________________________________
Vertebrate Embryology Lab Notes, Page 10 John Tran 2009
Spokes
Theca
Interna
.
Theca =
Case
Interna =
Inside
Develops
from ovary
interstitium
Theca
Externa
.
Theca =
Case
Externa =
Outside
Develops
from ovary
interstitium
Follicular
Cells/
Granulosa
Cells
.
Primary
Oocyte
.
Oo = Egg
PGC
Secondary
Oocyte
.
Oo = Egg
Primary
Oocyte
Antrum
.
Blood
Vessels of
Ovary
.
protect the ovum and is a
major player during
fertilization. Sperm must
break through this layer to
access the underlying zona
pellucida
Will be future portion of
corpus luteum that provides
progesterone
Will be future portion of
corpus luteum but as
collagenous and structural
support
Intermediate These cells make up the
Mesoderm
follicle
AKA
Urogential
Mesoderm
Develops
in the
graffian
follicle
Females start with primary
oocyte at birth. They are
arrested at Prophase I until
onset of puberty (2N, 4C)
Once primary Oocyte finish
Meiosis I they start Meiosis II
but arrest at Metaphase II
(1N, 2C)…Meiosis II will
only finish if a sperm enters
Large fluid filled space of the
follicle. Surrounds the ovum
with liquor folliculi
Name should be selfexplanatory.
that surround the ovum.
This is the corona radiata.
Innermost concentric
rings of follicular cells
surrounding the follicle.
Found easiest on
graaffian follicles
Outermost concentric
rings of follicular cells
surrounding the follicle.
Found easiest on graffian
follicles
They are all over the
place. I like to find a
primordial follicle and
point to the ring around
the ovum because those
are follicular cells
Find the ovum in a
primordial follicle
Find the ovum in a
mature follicle
Find a graafian follicle
and point to the large
cavity in the center.
If you look at the center
of the ovary, you notice
these weird twisted
shapes that are fairly
large… these are the
blood vessels for the
ovary… that’s why I used
to avoid the center
portions of the
ovary…there isn’t much
to find
______________________________________________________________________________
Vertebrate Embryology Lab Notes, Page 11 John Tran 2009
18 Hour Chick Embryo
Chick Embryo is barely forming… you don’t really see an outline of a body yet but you see
the start of neurulation
Term
Definition
Identify
Area
Pellucida
Check Greek/Latin Origin
Box
Roots
.
Luc =
Bright
Area of blastoderm that the
developing embryo lies on.
Area Opaca
.
Area of blastoderm that the
developing vasculature forms.
Further separated into area
vasculosa and area vitellina
Blood
Islands
.
Primitive
Streak
.
Midline thickening, denotes
site of neurlation to form the
neural tube
Hensens
Node
.
Thickened portion of
primitive streak. Important
organizer during neurulation.
Comparable to Spemanns’s
organizer in amphibians
Central and Bright. Oval
Shaped. Looks like a
halo around the embryo
Peripheral and Dark
compared to the central
area pellucida. Should
see spots…that’s the
blood islands
Small dark spots that
surround developing
embryo. They are found
more often towards the
caudal end of embryo
Point directly to the
dorsal midline portion of
sections. It’s where the
future spine will be ect
Streak also appears
“Fuzzy” it looks like a red
smear/smudge obvious
towards more caudal
regions
Look along midline axis.
Towards the center there
is a darker node or “spot”.
This dark spot is pretty
distinct
Primitive
Groove
Primitive
Ridge
.
.
.
Opac =
Shady
Mesoderm
This will form into the future
vasculature for the chick.
Future vitelline arteries and
veins
Neural
Ectoderm
Early sign that a neural tube is
forming. A starting feature of
neurulation
Neural
Ectoderm
Early sign that a neural tube is
forming. A starting feature of
neurulation
Slight depression or
“valley” like feature in
the neural ectoderm.
Point towards caudal end
because the tail region is
less developed and more
“primitive”
Slight raised ridges that
will later grow into more
pronounced neural folds.
Point towards caudal end
because the tail region is
______________________________________________________________________________
Vertebrate Embryology Lab Notes, Page 12 John Tran 2009
Neural
Groove
.
Neuro =
Brain
Neural
Ectoderm
This is the future lumen of the
neural tube. Is a more
developed version of the
primitive groove.
Neural
Folds
.
Neuro =
Brain
Neural
Ectoderm
This is the structure that
allows the neural grove to
become the neural tube.
Ridges along the grove fold
over. Is a more developed
version of the primitive ridge
less developed and more
“primitive”
More pronounced
depression or “valley”
like feature in the neural
ectoderm. Point towards
cranial end because this
region is more developed.
Neural groove may have
fully closed over to
become neural tube.
More pronounced raised
ridges running parallel to
the neural grove. Point
towards the cranial end
because the head region is
more developed.
______________________________________________________________________________
Vertebrate Embryology Lab Notes, Page 13 John Tran 2009
24 Hour chick Embryo: Chick is still forming in a linear fashion but major neural features
are more defined. The Head process is also more obvious
Term
Area Pellucida
Area Opaca
Check Greek/Latin Origin
Box
Roots
.
Luc =
Bright
.
Opac =
Shady
Blood Islands
.
Mesoderm
Cranial
Neuropore
.
Skin Ectoderm
.
Head
Mesenchyme
.
Mesoderm
Cranial
Intestinal Portal
.
Endoderm
Neural Groove
.
Neuro =
Brain
Neural
Ectoderm
Neural Folds
.
Neuro =
Neural
Neuro =
Brain
Pore =
Passage
Ecto = Outer
Neural
Ectoderm
Ectoderm
Definition
Identify
Area of blastoderm that the
developing embryo lies on.
Area of blastoderm that the
developing vasculature
forms. Further separated
into area vasculosa and area
vitellina
This will form into the
future vasculature for the
chick. Future vitelline
arteries and veins
Central and Bright.
Oval Shaped
Peripheral and Dark
compared to the central
embryo. Should see
spots…that’s the blood
islands
Small dark spots that
surround developing
embryo. They are
found more often
towards the caudal end
of embryo
Looks like a small
indent in the
prosencephalon
When the neural tube
forms, the cranial region
isn’t closed of yet. This is
the cranial opening.
This is the outermost layer
of cells that surround all of
the other internal structures.
This mesoderm forms the
head muscle and connective
tissue. Assumes a messy
mesenchymal organization
Will open up into the
foregut. Occurs because
the hypoblast/endoderm
needs to form a digestive
tract.
This is the future lumen of
the neural tube. Is a more
developed version of the
primitive groove.
This is the structure that
Point to outer most
layer/membrane in cross
sections. Easy!
Pick a cross section and
point towards the messy
looking arrangement of
cells found in between
the brain structures and
the skin ectoderm
Looks like a dark upside
down semi circle.
Found near the cranial
region…obviously. Best
seen on whole mounts
More pronounced
depression or “valley”
like feature in the neural
ectoderm. Point
towards cranial end
because this region is
more developed.
Neural groove may have
fully closed over to
become neural tube.
More pronounced raised
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Vertebrate Embryology Lab Notes, Page 14 John Tran 2009
Brain
Ectoderm
allows the neural grove to
become the neural tube.
Ridges along the grove fold
over.
Spinal Cord/
Neural Tube
.
Neural
Ectoderm
Synonymous with neural
tube. This becomes part of
the central nervous system.
Segmental Plate/
Paraxial
Mesoderm
.
Mesoderm
Somites
.
Soma =
Body
Mesoderm
Notochord
.
Noto =
Back
Mesoderm
Splan = ?
Pleur = Side
Mesoderm
and
Endoderm
Mesoderm that will turn
into the somites (future
musculature and skeletal
system of organism)
Future musculature and
skeletal system of
organism. Subdivided into
dermatome (future skin),
myotome (future Muscle),
sclerotome (future skeleton)
Future vertebral column.
Will be found in about 75
percent of the sections you
look at
Forms structures like Yolk
Sac and Allantois
Soma =
Body
Pleaur =
Side
Mesoderm
and
Ectoderm
Forms structures like
Amnion and Chorion
Lateral
Mesoderm
This is an internal cavity
that will hold various
organs in the body. Occurs
from the delamination of
lateral mesoderm into
Splanchnopleure .
Somatopleure
.
Coelom
.
ridges running parallel
to the neural grove.
Point towards the
cranial end because the
head region is more
developed.
Almost same structure
as the neural groove
except that the grove
folds over and forms a
tube. Point towards the
more cranial regions
because the head region
is more developed.
Find the notochord.
Then find aggregations
of mesodermal cells
lateral to the notochord.
They look like circular
or oval shaped masses
of cells lateral to the
notochord. One of the
easiest structures to spot
Small dark circle
located near dorsal
portions of sections
Easiest to spot towards
midsection cross
sections. Point towards
the double membrane
located ventral laterally
(endoderm + splanchnic
mesoderm)
Easiest to spot towards
midsection cross
sections. Point towards
the double membrane
located dorsal laterally
(ectoderm + somatic
mesoderm)
Easiest to spot towards
midsection cross
sections. Located the
dorsal somatopleure and
the ventral
______________________________________________________________________________
Vertebrate Embryology Lab Notes, Page 15 John Tran 2009
somatic and splanchnic
mesoderm.
splanchnopleure. There
should be a large white
void space in between
these two membranes…
look back at the lab
hand book because the
coelom can look very
different
33 Hour Chick Embryo: Chick is still forming in a linear fashion but cardio features can
now be seen
Term
Telencephalon
Check Greek/Latin
Box
Roots
Tele = Far
End
Cepha =
Head
Origin
Definition
Identify
Neural Tube
(Forebrain) Part of
prosencephalon. Forms
future cerebral
hemispheres
(Forebrain) Part of
prosencephalon. Forms
future thalamus and
hypothalamus. Also
forms the third ventricle
(Midbrain) Forms the
future midbrain
structures
1st Cranial most
section. Might want
to look for the cranial
neuropore as an
additional structure
2nd cranial most
section. Might want
to look for optic
vesicles as an
additional structure.
3d cranial most
section.
Diencephalon
Dien = ?
Cepha =
Head
Neural Tube
Mesencephalon
Mes =
Middle
Cepha =
Head
Met = ?
Cepha =
Head
Neural Tube
Metencephalon
.
Mylencephalon
.
Mylen = ?
Cepha =
Head
Neural Tube
Cranial
Neuropore
.
Neuro =
Brain
Pore =
Passage
Neural Ectoderm
Fund =
Down
Diencephalon
Infundibulum
Neural Tube
(Hindbrain) Part of
rhombencephalon.
Forms future
cerebellum and pons
(Hindbrain) Part of
rhombencephalon.
Forms future medulla
When the neural tube
forms, the cranial
region isn’t closed of
yet. This is the cranial
opening.
The downward
evagination from
diencephalon floor.
Forms the pituitary
gland with rathkes
4th cranial most
section
5th cranial most
section… kind of
looks narrow and
thinner
Looks like a small
indent in the
prosencephalon
It’s a darker spot on
the diencephalon
floor. In cross
sections it actually
dips down from
______________________________________________________________________________
Vertebrate Embryology Lab Notes, Page 16 John Tran 2009
Optic Vessicles
Opt = Eyes
Neural tube but
specifically
Diencephalon
Cranial Intestinal
Portal
Pore =
Passage
Endoderm
Somites
Soma =
Body
Mesoderm
Conotruncus
.
Ventricle
.
Sinoatrial
Endocardial
Tubes/
Mesoderm
Vent =
Body
Endocardial
Tubes/
Mesoderm
An atrium
in greco
roman
architecture
is a large
open space
in a
building
Endocardial
Tubes/
Mesoderm
Ectoderm
Neural Crest
Cells
Notochord
Noto =
pouch
Outward evagination of
diencephalon that then
forms optic cups/stalk
to make the eye
Will open up into the
foregut
Future musculature and
skeletal system of
organism. Subdivided
into dermatome (future
skin), myotome (future
muscle), sclerotome
(future skeleton)
Also called bulbis
cordis. Will ultimately
fuse with the ventricle
to help heart pump
blood
The portion of heart that
pumps the blood to the
rest of the body.
Largest chamber of the
heart
The portion of heart that
holds blood before it is
pumped into ventricle.
Smaller than ventricle
and muscle walls are
thinner
Dorsal NCC result in
melanocytes. Ventral
NCC result in
peripheral nervous
system. Head NCC
form muscles and
connective tissue in the
head
Chordamesoderm Future vertebral
diencephalon floor
Large lateral circular
protruding structures
from diencephalon
Looks like a dark
upside down semi
circle. Found near the
cranial
region…obviously
They look like
circular or oval
shaped masses of
cells lateral to the
notochord. One of
the easiest structures
to spot
On whole mounts,
conotruncus looks
darker, located more
cranially, and more
medial
On wholemounts,
ventricle looks larger,
lighter, located more
laterally…kind of
sticks out from the
body of the embryo.
Caudal to the bulbis
cordis
On wholemounts,
sinoatrial region looks
like a dark little
bubble located
directly caudad from
the ventricle
Aggregations of
mesenchymal cells
lateral to the spinal
cord
Small dark circle
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Vertebrate Embryology Lab Notes, Page 17 John Tran 2009
Back
Coelom
.
Splanchnopleaure .
Mesoderm
Lateral
Mesoderm
column. Will be found
in about 75 percent of
the sections you look at
This is an internal
cavity that will hold
various organs in the
body. Occurs from the
delamination of lateral
mesoderm into somatic
and splanchnic
mesoderm.
Splan = ?
Pleur = Side
Mesoderm and
Endoderm
Forms structures like
Yolk Sac and Allantois
Somatopleure
.
Soma =
Body
Pleaur =
Side
Mesoderm and
Ectoderm
Forms structures like
Amnion and Chorion
Neural Groove
.
Neuro =
Brain
Neural Ectoderm
This is the future lumen
of the neural tube. Is a
more developed version
of the primitive groove.
Neural Folds
.
Neuro =
Brain
Neural Ectoderm
This is the structure that
allows the neural grove
to become the neural
tube. Ridges along the
grove fold over.
Spinal Cord/
Neural Tube
.
Neural Ectoderm
Synonymous with
neural tube. This
becomes part of the
central nervous system.
located near dorsal
portions of sections
Easiest to spot
towards midsection
cross sections.
Located the dorsal
somatopleure and the
ventral
splanchnopleure.
There should be a
large white void space
in between these two
membranes
Easiest to spot
towards midsection
cross sections. Point
towards the double
membrane located
ventral laterally
Easiest to spot
towards midsection
cross sections. Point
towards the double
membrane located
dorsal laterally
More pronounced
depression or “valley”
like feature in the
neural ectoderm.
Point towards the
caudal region because
cranial regions
already fused into
neural tube
More pronounced
raised ridges running
parallel to the neural
grove. Point towards
the caudal region
because cranial
regions already fused
into neural tube
Almost same
structure as the neural
groove except that the
grove folds over and
______________________________________________________________________________
Vertebrate Embryology Lab Notes, Page 18 John Tran 2009
forms a tube. Point
towards the more
cranial regions
because the head
region is more
developed.
48 Hour Chick Embryo: Chick now turns on its left side. The embryonic vasculature and
blood vessels are the major changes in the chick.
Term
Definition
Identify
Stomodeum
Check Greek/Latin Origin
Box
Roots
Stom =
Ectoderm and
Mouth
Endoderm
contributions
Future oral cavity
Pharynx
.
???
Endoderm
Inner endodermal region
of highly complex
pharyngeal arch region.
Basically the back of
throat
Foregut
.
For = Before
Endoderm
Future esophagus,
trachea, lungs, stomach,
and accessory digestive
organs.
Stomach
.
Endoderm
Where the food is stored!
Yay this one is easy
Best seen in whole
mount. Point towards
region between optic
cup and 1st pharyngeal
arch. Looks like a
hollow pouch… kind
of hard to find at this
stage
This structure is
caudal to the
stomodeum. Find a
cross section and then
point to the large,
ventral, medial, hole
that is around the
pharyngeal arches
This structure is
caudal to the pharynx.
Find a cross section
and then point to the
large, ventral, hole
that is past the
pharyngeal arches.
Look for a developing
heart IE ventricles to
make sure you have
gone down caudally
enough
This structure is
caudal to the Foregut.
Find a cross section
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Vertebrate Embryology Lab Notes, Page 19 John Tran 2009
Duodenum
.
Allantois
Dorsal Aorta
Old latin
name meant
12 fingers
breadth…I
don’t know
what that
means :[
???
Endoderm
Part of the small
intestine. Small intestine
sub divisions are
Duodenum, Jejunum,
Ileum
Endoderm
Dor = Back
Aeiro- rise
or left
Ventr =
Body
Aeiro = rise
or lift
Pre = Before
Card = Heart
Ven = Come
Cardiac
Mesoderm
Contributes to the
excretory system and the
future cloaca…1/4
embryonic
membranes…used for
nitrogenous waste
disposal
Part of circulatory
system, forms future
descending aorta
Part of circulatory
system, forms future
aortic sac
Mesoderm
Part of circulatory
system, returns blood to
the heart
Ventral Aorta
.
Cardiac
Mesoderm
Precardinal Veins
.
Postcardinal
Veins
.
Post = After
Card = Heart
Ven = Come
Mesoderm
Part of circulatory
system, returns blood to
the heart
Internal Carotid
Arteries
.
Card = Heart
Mesoderm
Part of circulatory
system, returns blood to
the heart
and then point to an
extra large ventral
hole
This structure is
caudal to the Foregut
and Stomach. Find a
cross section and then
point to large, ventral,
hole that is found near
the liver rudiment
Look towards the tail
bud sections and point
towards a small
opening close to
ventral surface… it’s
not very large
Look for pair of blood
vessels located dorsal
medial to the gut
Look for pair of blood
vessels located ventral
medial to the gut
Look for circular
structures (slightly
larger than the
arteries) located
dorsal lateral to the
gut (lateral to the
dorsal aorta)…found
towards cranial
regions…thus the
prefix “pre”
Look for circular
structures (slightly
larger than the
arteries) located
dorsal lateral to the
gut (lateral to the
dorsal aorta)… found
towards caudal
regions…thus the
prefix “post”
Look for circular
structures (slightly
larger than the
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Vertebrate Embryology Lab Notes, Page 20 John Tran 2009
Mesoderm…
Pumps blood from left
related to aortic ventricle into the
sac and
circulatory system
precursor
ventral aorta
Aortic Trunk
Ventricle
Atrium
.
Sinus Venosus
.
Pericardial
Cavity
.
Descending Aorta
.
Ventr =
Body
Endocardial
Tubes/ cardiac
Mesoderm
The portion of heart that
pumps the blood to the
rest of the body. Largest
chamber of the heart
An atrium in
greco roman
architecture
is a large
open space
in a building
Sinus =
Hollow
Ven = Come
Endocardial
Tubes/ cardiac
Mesoderm
The portion of heart that
holds blood before it is
pumped into ventricle.
Smaller than ventricle
and muscle walls are
thinner
This is where the blood
returns to the heart.
Enters sinus venosus
before the atrium
Peri =
Around
Card = Heart
Cardiac
mesoderm
Cardiac
mesoderm
Mesoderm
This is the hollow
chamber that holds the
heart…I think of it as a
coelom-ish structure for
the heart
This is the fusion of the
dorsal aorta. Imporatant
arteries) located
ventral lateral to the
gut… found mainly in
cranial regions
This is one of the
most cranial
structures of the heart.
If you are moving in
cranial-caudal fashion
through slides, should
be first part of heart
you see in sections
Should be caudad to
the aortic trunk. Look
for a large hollow
circular structure
flanked by
endocardium and
myocardium. Easiest
way to differentiate
from atrium is that
Ventricle has thick
muscle walls
Should be caudad to
the ventricle. Look
for a large hollow
circular structure. It
has thin muscle walls
This is the most
caudal structure in the
heart. Move through
all the sections until
you reach this caudal
portion. Don’t
confuse with the
ventricle (the
ventricle is really big
so choose the smaller
circular structure)
Point to any area
lateral to the atrium or
ventricle. This is the
pericardial space
Look at sections
caudad to the heart.
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Vertebrate Embryology Lab Notes, Page 21 John Tran 2009
structure for the
mesonephric kidneys
that will later form
Dermatome
Derm = Skin
Sommites
Forms the future dermis
Myotome
Myo = ?
Sommites
Forms the future muscles
.
Scler = hard
Sommites
Forms the future
skeleton
Splanchnopleaure .
Splan = ?
Pleur = Side
Mesoderm and
Endoderm
Forms structures like
Yolk Sac and Allantois
Sclerotome
Somatopleure
.
Soma =
Body
Pleaur =
Side
Mesoderm and
Ectoderm
Forms structures like
Amnion and Chorion
Amnion
.
???
Sommatopleure
Chorion
.
???
Sommatopleure
Yolk Sac
.
???
Splanchnopleure
Telencephalon
.
Tele = Far
End
Neural Tube
¼ Extra embryonic
membrane. Responsible
for providing aqueous
environment
¼ Extra embryonic
membrane. Responsible
for providing gas
exchange
¼ Extra embryonic
membrane. Responsible
for nutrients
Part of prosencephalon.
Forms future cerebral
Look the dorsal
medial region of the
sections. Look for
one large circular
structure.
I like choosing
sections towards tail
region…Part of
sommite located
closest to skin
ectoderm
I like choosing
sections towards tail
region…In between
dermatome and
myotome
I like choosing
sections towards tail
region…Part of
sommite located
closest to the neural
tube
Easiest to spot
towards midsection
cross sections. Point
towards the double
membrane located
ventral laterally
Easiest to spot
towards midsection
cross sections. Point
towards the double
membrane located
dorsal laterally
Go to whole mount:
Point to large bubble
sac like structure
around embryo
Hard to differentiate
from Amnion. Point
to same region as the
Amnion
The whole embryo
kind of sits on the
entire yolk sac
Cranial most section.
Might want to look
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Vertebrate Embryology Lab Notes, Page 22 John Tran 2009
Cepha =
Head
hemispheres
Diencephalon
.
Dien = ?
Cepha =
Head
Neural Tube
Part of prosencephalon.
Forms future thalamus
and hypothalamus. Also
forms the third ventricle
Mesencephalon
.
Neural Tube
Forms the future
midbrain structures
Metencephalon
.
Mes =
Middle
Cepha =
Head
Met = ?
Cepha =
Head
Mylencephalon
.
Infundibulum
.
Rathkes Pouch
.
Isthmus
.
Cranial Flexure
.
Cran = Brain
Flex = Bend
Neural Tube
Eye Cups
.
Opt = Eye
Ectoderm
Turns the 33 hour chick
embryo’s linear body lay
out to this twisted body
lay out. Term used to
describe how head is
twisted to the left side
Future Eye
Pigmented Retina
.
Ectoderm
Future neural cells like
Mylen = ?
Cepha =
Head
Fund =
Down
Neural Tube
Part of
rhombencephalon.
Forms future cerebellum
and pons
Neural Tube
Part of
rhombencephalon.
Forms future medulla
Diencephalon
The downward
evagination from
diencephalon floor.
Forms the pituitary gland
with rathkes pouch
Oral Cavity
The upward evagination
from oral cavity. Forms
the anterior pituitary
gland with the
infundibulum.
Neural tube:
A constriction of the
Mesencephalon neural tube between the
and
mesencephalon and
Metencephalon metencephalon
for the cranial
neuropore as an
additional structure
Very cranial section.
Might want to look
for optic vessicles as
an additional
structure. First large
neural bulge
Second large neural
bulge
Third large neural
bulge
Fourth large neural
bulge… kind of looks
narrow and thinner
It’s a darker spot on
the diencephalon floor
It’s the little circular
bubble that is near te
infundibulum. It
evaginates from the
stomodeum.
Easiest to spot on a
whole mount. Find a
“dent” in between the
mesencephalon and
metencephalon on the
dorsal side.
Easiest to spot on a
whole mount. Just
point to the head
region
Huge circular bulges
coming out of the
prosencephalon.
Hard to miss
Look near
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Vertebrate Embryology Lab Notes, Page 23 John Tran 2009
bipolar, horizontal, or
ganglion cells in the eye
Sensory
Retina
.
Auditory
Vessicles
.
Tail Buds
.
.
.
.
.
Aud =
Hearing
Ectoderm
Future photoreactive
cells like rods and cones
Ectoderm
Future inner ear
Mesoderm
Forms the primitive tail
prosensephalon for
the bulging optic
cups. Thinner
structure than
pigmented. It is
located more medial
Look near
prosensephalon for
the bulging optic
cups. Thicker
structure than
sensory. It is located
more laterally.
Located near the
mylencephalon. Look
like circular
outgrowths from the
head
One of the most
caudal structures. Go
all the way to the end
of your slides
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Vertebrate Embryology Lab Notes, Page 24 John Tran 2009
72 Hour Chick Embryo
Stomodeum
.
Stom =
Mouth
Ectoderm and
Endoderm
contributions
Pharynx
.
???
Endoderm
Esophagus
.
Oesopho =
Gullet
Phagus =
Eat
Endoderm of
foregut
Trachea
.
Ventral
Diverticulum
of foregut
Lung Buds
.
Bifurcation of
the primordial
trachea
Future oral cavity
Best seen in whole
mount. Point towards
region between optic
cup and 1st pharyngeal
arch. Looks like a
hollow pouch… kind
of hard to find
Inner endodermal region This structure is
of highly complex
caudal to the
pharyngeal arch region.
stomodeum. Find a
Basically the back of
cross section and then
throat. Caudal to the
point to the large,
stomodeum but cranial to ventral, hole that is
the larynx
around the pharyngeal
arches
This is how food goes
Parallel to the trachea
from the mouth to the
but located dorsal.
stomach.
Small circular
structure near/after
the pharyngeal area
This is the future
Parallel to the
windpipe. Brings air
esophagus but located
down into the bronchi
ventral. Small
circular structure near
the pharyngeal
area…caudally the
lung buds can be
found
This will mature into the Look for a pair of two
full Lungs. Responsible circular structures
for respiration
ventral lateral to the
esophagus. They’re
easy to spot because
they look like bubbles
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Vertebrate Embryology Lab Notes, Page 25 John Tran 2009
Stomach
.
Endoderm of
foregut
Where the food is stored!
Yay this one is easy
Duodenum
.
Old latin
name meant
12 fingers
breadth…I
don’t know
what that
means :[
Endoderm of
foregut
Part of the small
intestine. Order of small
intestine sub divisions
are Duodenum, Jejenum,
Ileum
Jejunum
.
???
Endoderm
midgut
Part of the small
intestine. Order of small
intestine sub divisions
are Duodenum, Jejenum,
Ileum
Ileum
.
???
Endoderm
midgut
Part of the small
intestine. Order of small
intestine sub divisions
are Duodenum, Jejenum,
Ileum
Cloaca
.
???
Endoderm
Where the digestive tract
and the urinary tract
excrete their waste. This
cloaca will divide in
growing from the
foregut
This structure is
caudal to the Foregut.
Find a cross section
and then point to an
extra large ventral
hole. I distinguish the
stomach from the
duodenum or
esophagus because
the stomach should
have a thicker tissue
lining. The lumen is
also larger as wel.
This structure is
caudal to the
Stomach. Find a
cross section and then
point to large, ventral,
hole that is found near
the liver
rudiment…the
duodenum is usually
surrounded by the
dark spotty tissue of
the liver
This structure is
caudal to the
Duodenum and
Stomach. Find a
cross section and then
point to large, ventral,
hole that is caudal to
the liver
This structure is
caudal to the jejunum.
Find a cross section
and then point to
large, ventral, hole
that is found towards
the more caudal
sections
Look towards the tail
bud at the most caudal
setions. It will be the
largest, most medial,
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Vertebrate Embryology Lab Notes, Page 26 John Tran 2009
Dorsal Aorta
.
Ventral Aorta
.
Precardinal Vein
.
Postcardinal Vein
humans and mamals so
that the urinary tract is
separate from the
digestive tract… but
vertberates like birds still
have a single cloaca
Part of circulatory
system, forms future
descending aorta
Part of circulatory
system, forms future
aortic sac
circular lumen. You
might see a septum
that divides the cloaca
into two circular
lumens…this is
normal
Look for circular
lumen located dorsal
lateral to the gut
Look for circular
lumen located ventral
lateral to the gut
Look for circular
lumen (slightly larger
than the arteries)
located lateral to the
dorsal aorta…found
towards cranial
regions
Look for circular
lumen (slightly larger
than the arteries)
located lateral to the
dorsal aorta… found
towards caudal
regions
Look for circular
structures (slightly
larger than the
arteries) located
ventral lateral to the
gut… found only in
cranial regions
Look for one circular
lumen located dorsal
medial… It’s the
same place where
dorsal aorta used to
be…remember to
look at sections that
are caudad to the
heart (if not the dorsal
aorta have not fused
yet)
This is hard. You
have to keep track of
Dor = Back
Aeiro- rise
or left
Ventr =
Body
Aeiro = rise
or lift
Pre = Before
Card = Heart
Ven = Come
Mesoderm
Mesoderm
Part of circulatory
system, forms, returns
blood to the heart
.
Post = After
Card = Heart
Ven = Come
Mesoderm
Part of circulatory
system, forms, returns
blood to the heart
Internal Carotid
Arteries
.
Card = Heart
Mesoderm
Part of circulatory
system, returns blood to
the heart
Descending Aorta
.
Dorsal Aorta
1,2,3 aortic arch
.
Mesoderm
The fusion of the two
dorsal aorta. This fusion
occurs once you move
caudad to the developing
heart. Is an important
structure for the
mesonephric kidneys and
will branch out to make
the glomeruli
(capillaries) for the
mesonephric kidney
Part of the complex
pharyngeal arch
Mesoderm
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Vertebrate Embryology Lab Notes, Page 27 John Tran 2009
system…will form
arteries, veins found in
the head and neck
Conotruncus
AKA Bulbis
Cordis
.
Bul = Bulb
Chord =
Cord
… I guess it
describes the
shape
Endocardial
Tubes/ cardiac
Mesoderm
Also called bulbis cordis.
Will eventually fuse with
the primitive ventricle to
form adult ventricle
Ventricle
.
Ventr =
Body
Endocardial
Tubes/ cardiac
Mesoderm
The portion of heart that
pumps the blood to the
rest of the body. Largest
chamber of the heart
Atrium
.
An atrium in
greco roman
architecture
is a large
open space
in a building
Endocardial
Tubes/ cardiac
Mesoderm
The portion of heart that
holds blood before it is
pumped into ventricle.
Smaller than ventricle
and muscle walls are
thinner
Sinus Venosus
.
Sinus =
Hollow
Ven = Come
Cardiac
mesoderm
This is where the blood
returns to the heart.
Enters sinus venosus
before the atrium
all the arches and
count them to know
which arch number
you are on. Arches
are basically blood
vessels so look for
circular lumens. They
always come in a pair
(left and right) and are
located lateral from
the pharynx
It is located cranial to
the ventricle. One of
the earliest structures
you will spot on a
section if you are
moving in cranial
caudal fashion. Look
for the typical circular
lumen near cardiac
region
Should be caudad to
the bulbis cordis.
Look for an extra
large hollow circular
structure flanked by
endocardium and
myocardium. Easiest
way to differentiate
from atrium is that
Ventricle has thick
muscle walls
Should be caudad to
the ventricle. Look
for a large hollow
circular structure. It
has thin muscle walls
when compared to the
ventricle.
This is the most
caudal structure in the
heart. Move through
all the sections until
you reach this caudal
portion. Don’t
confuse with the
ventricle (the
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Vertebrate Embryology Lab Notes, Page 28 John Tran 2009
Vitelline Artery
.
Vitell =
Yolk
This is the oxygenated
blood that will flow into
the embryo
Vitelline Vein
.
Vitell =
Yolk
This is the deoxygenated
blood that will drain out
of the embryo
Wing Bud
.
Apical
Ectodermal
Ridge
.
Sommatic
Mesoderm
Amnion
.
.
Somatic
Mesodermal
Mesenchyme
This wing bud will
extend out in progress
zones to fully form
wings on either side of
the body
Ecto = Outer
Skin Ectoderm
This is the leading edge
of how the bud forms,
extends, and matures
into a fully developed
wing
???
Sommatopleure
¼ Extra embryonic
membrane. Responsible
for providing aqueous
environment
ventricle is really big
so choose the smaller
circular structure)
You can find this
pretty easily on a
whole mount. Look
for a dark and large
artery that transverses
the embryo at mid
section…
You can find this
easiest on a cross
section. Look for two
large circular lumens
that appear caudally
from the liver region.
Veins need to drain
blood to the liver/
ductus venosus first.
Remember blood
vessels are always
circular lumens and
veins tend to have
larger lumens than
arteries
Obvious. Look at
lateral sides of the
body and you will see
these bud shaped
outgrowths of
mesodermal
mesnechyme. Verify
by spotting the darker
edge of the apical
ectodermal ridge
Look for the darker,
thicker, outer rim pf
skin ectoderm that
surrounds the wing
bud.
Go to whole mount:
Point to large bubble
sac like structure
around
embryo…directly
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Vertebrate Embryology Lab Notes, Page 29 John Tran 2009
next to the chorion
Chorion
.
???
Sommatopleure
¼ Extra embryonic
membrane. Responsible
for providing gas
exchange
Yolk Sac
.
???
Splanchnopleure
¼ Extra embryonic
membrane. Responsible
for nutrients
Allantois
.
???
Splanchnopleure
¼ Extra embryonic
membrane. Responsible
for waste disposal.
Telencephalon
.
Tele = Far
End
Cepha =
Head
Neural Tube
Part of prosencephalon.
Forms future cerebral
hemispheres
Diencephalon
.
Dien = ?
Cepha =
Head
Neural Tube
Part of prosencephalon.
Forms future thalamus
and hypothalamus. Also
forms the third ventricle
Mesencephalon
.
Mes =
Middle
Cepha =
Head
Neural Tube
Forms the future
midbrain structures
Metencephalon
.
Met = ?
Cepha =
Head
Neural Tube
Myelencephalon
.
Mylen = ?
Cepha =
Head
Neural Tube
Part of
rhombencephalon.
Forms future cerebellum
and pons
Part of
rhombencephalon.
Forms future medulla
Go to whole mount:
Hard to differentiate
from Amnion. Point
to same region as the
Amnion on a whole
mount…directly next
to the amnion
Go to whole mount:
The whole chick
embryo kind of sits on
the entire yolk sac
Go to whole mount:
Look towards the tail
bud sections and point
towards a small light
colored bubble close
to ventral surface…
it’s not very large
In cranial caudal
direction it is the 1st
Cranial most section.
Might want to look
for the nasal pits as
verification structure
In cranial caudal
direction it is the 2nd
Cranial most section.
Might want to look
for optic vessicles,
pineal gland, or
infundibulum as
verification structures.
In cranial caudal
direction it is the 3d
Cranial most section.
I usually look for the
isthmus as a
verification
In cranial caudal
direction it is the 4th
Cranial most section.
In cranial caudal
direction it is the 5th
Cranial most section.
I like to look for the
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Vertebrate Embryology Lab Notes, Page 30 John Tran 2009
Infundibulum
.
Rathkes Pouch
.
Pharyngeal
Groove/Cleft
.
Pharyngeal
Pouch
Fund =
Down
Diencephalon
The downward
evagination from
diencephalon floor.
Forms the posterior
pituitary gland
Oral Cavity
The upward evagination
from oral cavity. Forms
the anterior pituitary
gland
Related to
the pharynx
Pharyngeal
Ectoderm
Refer to the Pharyngeal
Handout
.
Related to
the pharynx
Pharyngeal
Endoderm
Refer to the Pharyngeal
Handout
Pharyngeal Arch
.
Related to
the pharynx
Mandiubular
Process
.
Mandible =
Jaw
This is the mass of tissue
that will surround the
aortic arches. Each arch
#1-4 will also house a
cranial nerve.
Pharyngeal
Arch 1
Forms the future lower
jaw….the mandible!
Jaws are really
auditory vesicles as
verification
It’s a darker spot on
the diencephalon
floor. In cross
sections, you can
actually see a bubble
pop out from the brain
(this is the
evagination)
It’s the little circular
bubble that is near the
infundibulum. It
evaginates from the
stomodeum.
Go to sections where
the pharyngeal area is.
Point to the grooves
from OUTSIDE the
pharyngeal area. Its
called a groove
because it looks like
outside the pharynx
the ectoderm got
sucked down and
made a groove
Go to sections where
the pharyngeal area is.
Point to the pouches
from INSIDE the
pharyngeal area…its
called a pouch
because it looks like
the pharynx “pouched
out”
Find the aortic arch.
Then there should be
a dark, mesenchymal,
mass of tissue that
surrounds the blood
vessel (looks like
somite structures but
located near the
pharynx instead)
Go to pharyngeal arch
1. Point to the caudal
portion of the tisssue
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Vertebrate Embryology Lab Notes, Page 31 John Tran 2009
Pharyngeal
Arch 1
powerful… lots of force
when chewing food
Forms the future top
portion of the jaw! Jaws
are really powerful…
lots of force when
chewing food
Associated with
semilunar ganglion. Is
the fifth cranial nerve.
Composed of the
opthalic, mandibular,
and maxillary branches
Maxiallary
Process
.
Trigeminal Nerve
.
Tri = Three
First Aortic
Arch
Acousticofacialis
Nerve
.
Combo of
Acoustic and
Facial
nerves
Second Aortic
Arch
Responsible for two
nerves, Auditory nerve
and the facial nerve.
Spinal Ganglion
.
Neural Crest
Cell
Ganglia are cluster of
neural cells. They are
important for the sensory
information being
consolidated from the
PNS before being sent to
the CNS
Eye Cup
.
Evagination
from lateral
sides of
Diencephalon
Forms future retina.
Remember there is the
thicker sensory retina
and the thinner
pigmented retina
Pigemented
Retina
.
Eye Cup
Thin outer layers of the
optic cups that contain
pigment granules
mass. Closer to the
pharynx
Go to pharyngeal arch
1. Point to the cranial
portion of the tissue
mass. Closer to the
stomodeum
Very easy to spot.
Look towards the
mesencephalon. It is
one of the first cranial
nerves you can spot.
Look for three, dark,
circular spots located
laterally on each side
of the brain.
Usually located
proximal to the
auditory vesicles
(obviously since
nerve deals with
hearing). It is a big
dark spot located on
the lateral sides of the
brain. Usually around
the mylencephalon
region.
All ganglia look the
same, they are small,
circular, dark, spots.
The spinal ganglia are
located directly lateral
to the neural tube so
they are very easy to
find.
Look for the lateral
bulges/bulges around
the diencephalon.
Bulges look huge on
cross sections but eye
cups look like round
dark spots on a whole
mount
Locate eye cups.
Point towards to the
thin outer layer…will
look darker
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Vertebrate Embryology Lab Notes, Page 32 John Tran 2009
Sensory Retina
.
Eye Cup
Nasal Pit
.
Facial Bulges
Lateral Nasal
Process
.
Medial Nasal
Process
.
Mesonephric
Duct
.
Mesopnephric
Tubule
.
.
.
.
.
.
.
.
The thick inner layers of
the optic cups, will form
the future rods, cones,
bipolar cells ect
Future nose and nasal
cavity
Locate eye cups.
Point towards the
thick inner layer
Locate the
mylencephalon
region. Look at
ventral lateral region
of the head. There are
dark, thick,
invaginating portions
of skin ectoderm
Facial Bulges
Future side cheek portion Locate the nasal pit.
of face
Point towards the side
of the nasal pit more
lateral on the head
Facial Bulges
Future top lip portion of
Locate the nasal pit.
face
Point towards the side
of the nasal pit more
medial on the head
Intermediate
Embryonic Kidney, site
A longitudinal
Mesoderm
where all the waste
structure the stretches
from urogential drains
the length of latter
region
half of the body. One
circular lumen located
on each lateral side in
the mesonephric
kidney
Intermediate
Embryonic Kidney, site
This is the mess of
mesoderm
where the waste is
tubules (look like
from urogenital filtered
scattered holes from a
region
sponge) that runs
parallel to the dorsal
aorta
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Vertebrate Embryology Lab Notes, Page 33 John Tran 2009
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