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134 Cards in this Set

  • Front
  • Back
Where does the liver epithelium originate?
Where does the salivary gland originate?
Where does the CNS originate?
What does the neuroectoderm form?
brain, spinal cord, pars nervosa of the pituitary, opitc nerve, retina, pigment epithelium, iris
Does the neuroectoderm form neural cells?
Where does the sclerotome come from and what does it form?
from teh somatocoele (from somite)

Becomes the intervetebral disks and bone and vetebrae
What does the myotome come from? What does it form?
From demomyotome from somatocoele from the somite

Forms DORSAL skeletal mm
Where does the dermatome come from? What does it form?
from the dermomyotome from the somatocoele from the somite.

Forms the VENTRAL skeletal mm

From which type of cells do somites come from?
From epiblast--all layers endoderm, mesoderm and ectoderm arise from the epiblast
Where does the inner ear originate? What about the middle ear?
Inner ear from ectoderm

Middle ear from endoderm
Where does the thymus and thyroid originate?
from the endoderm
What does teh ectoderm form?
skin, hair nails, eye lens and cornea, inner ear labrynith, anterior pituitary, sweat, sebaceous and mammary glands.
Where is neuroectoderm found?
above the notochord (in the middle)
Where does a somite orginitate from?
From the undifferientiated mesoderm
What is another name for the splanchnic mesoderm?
What does the early somite have? What does it differentiate into?
a somatocoele

diff to dermomyotome and sclerotome
Where does the UG come from?
urogenital from intermediate mesoderm
What makes the umbilicus?
The yolk sac and the connecting stalk
Where is the allantosis and what does it become?
Blind ended sac from the gut tube becomes the UG sinus then the embryo's bladder then becomes the urachus AKA median ligament
When does the yolk sac detatch?
6 weeks
When does the rostal neuropore close?
25 days
On the 23 day which brain structures have formed?
When does the caudal neuropore close?
27 days
When are somites formed?
During the formation of the neural tube. They form at the same time as nural crest cells
What do neural crest cells migrate as?
When does the neural plate form?
Day 18
When does the neural tube form?
Day 19-24
What is the neural plate made of?
made of ectoderm
What types of myofibers allow aid in neural tube formation?
apical actin in the ectoderm
What does the septum trnasversum help to form and what is its remnant in the adult?
forms liver, heart, diaphragm

separates the pericardial and peritoneal cavities

degenerates to the central tendon
What does the lateral plate medoderm consist of and what does it form?
EX. ribs, sternum, bones, dermis, blood vessels


ex. smooth mm and CT of gut
non bone CT
lung CT
what does the endoderm form?
alimenatry canal epithelium, pancreas, liver epithelium, salivary glands, palatine and lingual tonsil epithelium, thyroid and parathyroid glands, thymus, lung thrachea and larynx, middle ear
What are the forms of early mesoderm?
bood vessesls (endothelium and smooth mm) in all tissue


intermediate: UG

lateral plate (somatopleure) peripheral skeleton and dermis

lateral plate: splanchnopleure: smooth mm, vessesl and CT around GI and bladder

Non-specific dura and arachnoid, RBCs, WBC

Body: PNS, adrenal medulla, malanocytes
Where does bone and cartilage in the head come from?
from the neural crest cells (mesoderm)
What is an exception of the somitomeres which form the facial mm?
they have myotome but NO scleotome

Follow the migration of the neural crest cells?
from the dRG to theventral ramus, the sympathetic chain to adrenal medulla to pre aortic ganglion to ps in the gut and also to melanocytes
What happens to aortic arches 1 and 2
they degenerate
What is the fate of aa 3?
carotid aa
what is the fate of aa 4
r subclavian part of it
l aortic arch
What is the fate of aa 6?
pulmonary aa and ductus arteriosis
Which n is aaociated with branchial arch 1 mandibular and maxillary?
mandibular V3, maxillary V2
Which n is associated with ba's 2,3,4/6
2 facial
3 glossopharyngeal
4/6 vagus

2,3,4 = 7,9,10
What mm are associated with branchial arches 1,2,3,4,6?
1 mm of mastication (V)
2 mm of facial expression (CN 7)
3 stylopharyngeus (CN 9)
4 pharyngeal and laryngeal mm (CN 10)
Where does Rathke's pouch come from? What does it form/
Rathke's pouch

from above teh first arch forms anterior pituitary
What is the stomadeum and what does it form?
arises from ectoderm and endoderm (no mesoderm) is the embryonic mouth.

In between th emaxillary and mandibular parts of the 1ST ARCH!!

mesoderm is NOT in oral plate, so it splits
Which n is aaociated with branchial arch 1 mandibular and maxillary?
mandibular V3, maxillary V2
Which n is associated with ba's 2,3,4/6
2 facial
3 glossopharyngeal
4/6 vagus

2,3,4 = 7,9,10
What mm are associated with branchial arches 1,2,3,4,6?
1 mm of mastication (V)
2 mm of facial expression (CN 7)
3 stylopharyngeus (CN 9)
4 pharyngeal and laryngeal mm (CN 10)
Where does Rathke's pouch come from? What does it form/
Rathke's pouch

from above the first arch forms anterior pituitary. Midline formed from 1st arch
What is the stomadeum and what does it form?
arises from ectoderm and endoderm (no mesoderm) is the embryonic mouth.

In between th emaxillary and mandibular parts of the 1ST ARCH!!

mesoderm is NOT in oral plate, so it splits
What forms from the 1st groove?
external auditory meatus
What forms form the first pouch?
The tympanic cavity and nauditory tube
What forms from the second pouch?
The palatine tonsil
What forms from the 3rd pouch?
The parathyroid and thymus
What forms from teh 4/5 pouch?
parathyroid , c cells of thyroid
When does the stomatodeum open?
day 26
When do the branchial arches form?
days 23-27
How does the cervical sinus form?
grows OVER the 3rd and 4th arches to form the CERVICAL SINUS
What do the 4th and 6th arches give rise to?
The larynx
Where does the anterior 2/3 of the tongue originate? post 1/3?
ant 2/3 from 1st branchial arch

post 1/3 from the 3rd arch
Which structures are within the branchial arch?
aortic arch, cartilage (neural crest derivative), muscle and cranial N.
What is within the pharyngeal pouch?
calcitonin and thymus cells
What is the fate fo the branchial GROOVE?
it will disappear
Where is the foramen cecum formed?
from arch 3 midline
Where is the espophagus formed?
arch 6 Midline
Where are the aretenoids from?
from arch 4/6 midline
Where is the epiglottic swelling?
arch 4 midline
What is the fate of pharyngeal pouches 2-6?
They fuse, form a cervical sinus then involutes.

If does NOT involute can form a cyst
What does meckels cartilage form? Where does it originate?
initiates mesoderm around it to do intramembranous ossificaton

forms the sphenomandibular ligament

from arch 1
What cartilage is formed from arch 2?
hypoid bone
styloid ligament
sphenoid bone
What cartilage is formed from arch 3?
greater cornu of HYOID
What cartilage is formed from arch 4?
thyroid cartilage of larynx
What cartilage is formed from arch 6?
cricoid cartilage
When does the notochord induce differentiation of the somites? When is the differentiation of the lateral plate nearing completion?
early 4th week initiation by end of 4th week lateral plate differentiation is nearly done
When is the blastymal skeleton condensed?
5th week

blastymal skeleton is just condensation of MESENCHYME
When does chondrification begin?
in the 6th week
When do the PRIMARY ossification centers begin?
weeks 7-12
When do the SECONDARY ossification centers begin?
birth to 9th year
When do the epiphyseal plates fuse?
18-25 years
Which differentiated product of the somite results in HYPAXIAL structures?

Which differentiated product of the somite results in EPAXIAL structures?

deep back mm
what is it called when scelrotome fails to divide and migrate? what is the result?
hemivertebra could result in scoliosis
Which of the sacral bones fuses first?
The lowest which is why its the smallest
How many sclerotomes are involved in EACH vertebral segment?
When do myotomes form? What do they form?
form in 4-5 week

myotomes form myoblasts which fuse to form skeletal mm
When do axons grow out of the CNS?
week 5--follow myoblasts
What do axons divide into?
divide to follow pre and post axial mm groups.

flexors and extensors
When do axons mirgate to tehir final destination?
5th and 6th week
When do mm begin to function?
17-20 weeks

about 5 mos
When dose myleination of the lower extremeties begin?
2 yrs
Which way does the upper limb rotate?
lateral (outward) rotation
what is syndactily? Polydactaly?
fusion of digits

extra digits
What is amelia? Meromelia?
absense of a limb

absence of PART of a limb
How does the lower limb rotate?
inward (medial) rotation
What induces the differentiation of somites?
the notochord
Which is more medial somatopleure or splanchnopleure?
What does splanchnic mean?
Where is the primary ossification center found? The secondary?
primary in the diaphysis

secondary in the epiphysis
what forms the nucleus pulposis?
the notochord
What forms the annulus fibrosis?
the sclerotome
When does the sacrum fuse with the rest of the body?

When does the arch fuse with the TP?
8 years

2-5 yrs
What is the function of the BMP 4, MYF5, PAX3?

What types of mm don't have BMP 4?
bone morphogenic protein
all three genes work togehter to form body wall and limb mm
What is the hypomere?
The original mesoderm differentiates into three sections. The hypomeric mesoderm is the most VENTRAL region. It is fated to further differentiate into limbs, peritoneum, gonads, heart, blood vessels and mesenteries.
What is the epimere?
The original mesoderm differentiates into three sections. The epimeric mesoderm is the most DORSAL region. It separates longitudinally into discrete clumps of mesoderm termed SOMITES. Each somite is further split into dermotome, myotome, and sclerotome segments.
What does the hypomere do?
Wraps around bony elements nerves split into pre and post axial
What is the differentiation sequence of dermomyotome?
deliamination-separate from lamina at ends of stack



Determination--must be mm cells specifically

Differentiation--fuse to form myotubules
What is interesting about satellite cells?
They can regenerate

myogenic precursor to muscle fiber directly!
What steps are involved in forming a mm fiber? What cells can bypass some steps?
myogenic precursor
embryonic myoblasts
primary microtubule
secondary microtubule
muscle fiber

fetal myoblasts go from myogenic precursors all the way to the secondary microtubule

satellite cells go directly frommyogenic precursors to muscle fiber
Which limbs develop first?
upper limbs
Why are bones deep to mm?
because hypomere migrates superficial to teh somatopleure
mm ventral to bones are ___?

mm dorsal to bones are ___?
ventral preaxial

dorsal postaxial
What can cause meromelia?
Talidamide used for cancer and aids patients now used to be for pregnant women until babies born w/o some parts of limbs
What does the yolk sac form?
germinal cells, blood cell development
What does the chorionic membrane fuse with?
with the amnionic membrane during the fetal period
What functions does amnionic fluid provide?
temperature regulation
fluid exchange
permit symmetrical growth
Where does amnionic fluid come from?
the placenta early
amninonic membrane
embryonic/fetal urine
trahcobronchial passages
What is oligohydraminos and why is it caused?
inadequate amnionic fluid levels due to dysfunction in kidney
Which cavity grows faster chorion or amnion?
amnionic cavity
What does the placenta come from?
the villius chorion
What is the gut filled with? Why is this a good thing?
Filled with metonium, dead cells don't want them in the lungs
How can you estimate the day of fertilization?
take the last normal menstural peroid and subtract 2 weeks.
What is the LNMP?

What is the EDF?
last normal menstrual period

estimated day of fertilization
What weight is necessary for viability?
500g (about 1lb)
What is the difference between surviving and thriving?
Survive first, but may not gain weight

If gaining weight and growing then thriving
What is quickening?

When does this happen?
When the baby starts to kick...1st brain function

17-20 weeks (5mos)
Whihc trimester contans both previable and viable stages?
2nd trimester

viable in the 3rd
Why do babies die under 500g? What test can be done to detect this problem?
inadequate lung development
could do amniocentisis to check
What is the difference between dizygotic and monozygotic twins?
mono from the same egg--identical

di from two eggs, 2 fertilizations fraternal
Which form of in utero testing is safest?
what happens in amniocentesis and chorionic villus sampling? When can the tests be done? How safe are they?
amnio--needle aspiration done at 12-18 wks safest

CVS--snip the villi 10-12 weeks--a little earlier

Both relatively safe

between .25 and 1%

amnio slightly safer
Is a insult earlier more or less detrimental to development?
earlier more detremental. If before gastrulation then baby dies (before 3wk)

In wk 3-9 form organs so maybe a problem but still can thrive

After 10 wk if no problem then can make it, less severe defects
What is a cleft?
formed by failed fusion

failure of organ to develop at all

Inductive stimulus in an abnormal place

two inductions
What is a stenosis?
What is a fistula?
What is a cyst?
What is an artesia?
stenosis= abnormal narrowing
fistula= abnormal connection
cyst= sturcture grows where it shouldn't
artesia=blind tube
what is a cause of developmental problems that may not be thought of first?
multiple pregnancy