Embryology II: Neurulation/Skeletal System Study Aid
8/6/2010 Nickalus Khan
Disclaimer: You need to know what comes from each of the germ layers (neurectoderm, neural crest,
ectoderm, mesoderm, endoderm) well for this exam!
Questions (1-60)
1. Describe the process of neurulation
2. What do notochordal cells migrating forward forming a shield shape overlying structure give rise
to?
3. What does neuroectoderm give rise to?
4. How does the neural tube form?
5. What does the neuropore communicate with?
6. As neural folds approach midline, differentiate, and detach laterally what do they form?
7. What does neural crest give rise to?
8. What does the mantle layer of the spinal cord form from?
9. What does the marginal layer of the spinal cord form from?
10. What forms the ventricular layer of the spinal cord?
11. What divides the mantle zone of the spinal cord into two layers? What does this separate?
12. What layers in spinal cord between white mater? Gray mater?
13. What forms the wall of the third ventricle in the brain?
14. Describe the flow of CSF .
15. What are the three primary vesicles the neural tube dilates into?
16. What does the forebrain (prosencephalon give rise to?)
17. What does telencephalon give rise to?
18. What does diencephalon give rise to?
19. What is the lateral wall of the third ventricle?
20. What dilation gives rise to midbrain?
21. What dilation gives rise to pons and cerebellum?
22. What dilation gives rise to medulla?
23. In the floor of the 4th ventricle what is the arrangement of the alar and basal plate?
24. What does neurectoderm give rise to?
25. What does the muscokeletal system derive from mainly?
26. What does proliferation of mesoderm near the notochord produce?
27. What is between lateral plate and paraxial mesoderm?
28. What does paraxial mesoderm form?
29. What three regions does each somite have?
30. What are less well organized regions of paraxial mesoderm cranially called?
31. What is a sclerotome made of?
32. How many sclerotomes make up a vertebral body?
33. What does the remnant of the notochord form?
34. What does the bones of the face form from (germ layer)?
35. What does the rest of the cranial vault form from?
36. What does a dermatome form?
Embryology II: Neurulation/Skeletal System Study Aid
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8/6/2010 Nickalus Khan
What does a myotome form?
What happens when the neural tube fails to close caudally?
What are some clinical signs of spina bifida?
What can meningomyelocele lead to?
What is Rachiscisis?
What happens with the neuropore fails to close cranially?
What causes clinical presentation of anencephaly?
What gives rise to the intrinsic muscles of the back?
What does hypomere give rise to?
What gives rise to limb bones?
What sends messages into underlying mesenchyme for limb differentiation?
What are the first bones of the limb to develop?
Where did parietal mesoderm come from?
What forms the digits of the hand? What does a failure of this process cause?
What is it called when there is a complete absence of limbs? Partial?
What does parietal lateral plate mesoderm give rise to?
What does visceral lateral plate mesoderm give rise to?
Describe the formation of the skeletal system.
Quiz Questions (at least 2 will be on Block I Exam)
55.
56.
57.
58.
59.
60.
The posterior neuropore provides a communication between what two spaces?
Cells of the adrenal medulla are derived from _______.
The vertebrae are derived from segmental _________.
What part of the brain’s ventricular system is derived from the diencephalon?
The membrane lining the abdominal cavity is derived from what division of mesoderm?
The sulcus limitans divides the developing central nervous system into what two major
functional areas?
Answers:
1.
Cells invaginate through primitive pit and migrate towards buccopharyngeal membrane
2.
Neurectoderm
3.
CNS and retina (remember what is in the CNS—see Embryo I q’s)
4.
Neural folds come together in midline over neural groove and fuse, neuropore then zips up
cranially and caudally
5.
Amnion cavity
6.
Neural Crest Cells (remember what neural crest gives rise to!)
7.
See below
Embryology II: Neurulation/Skeletal System Study Aid
8/6/2010 Nickalus Khan
A. Melanocytes
B. Cartilage and bones in head from pharyngeal arches
C. C cells of thyroid

Regulates calcium metabolism (calcitonin)
D. Aorticopulmonary septum
E. Odontoblasts
F. Adrenal Medulla
G. Sensory and Motor Ganglia
H. Schwann Cells
8.
Neuroepithelial cells that differentiate into neuroblasts
9.
Neuroblasts that differentiate into neurons and processes that extend into marginal layer
10.
Neuroepithelial cells that do not differentiate
11.
Sulcus limitans (Alar and Basal plate) Alar=Sensory, Basal=motor. Separates sensory and motor
functions
12.
Marginal Layer, Mantle layer, respectively
13.
Thalamus, hypothalamus
14.
CSF is produced in lateral ventricle (choroid plexus) third ventriclefourth
ventriclesubarachnoid space-reabsorbed through arachnoid villi
15.
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Forebrain (Proscencephalon), Midbrain (mesencephalon), Hindbrain (Rhombencephalon)
Telencephalon, Diencephalon
Cerebral hemispheres
Thalamus, hypothalamus
Thalamus (diencephalon)
Mesencephalon
Metencephalon
Myelencephalon
Alar is lateral to basal (remember alar is sensory and basal is motor)
See below
A. CNS, Retina, CN II
B. Neurohypophysis
C. Astrocytes, Oligodendrocytes
Mesoderm
Paraxial mesoderm (literally- around the axis), remaining mesoderm is called lateral plate
Intermediate mesoderm
Somites
Sclerotome, Dermatome, Myotome
Somiteomeres
31.
Medial and ventral cells that migrate away and head toward notochord that becomes bone and
cartilage of vertebral column
32.
2, caudal and cranial portion of different sclerotomes fuse to form v. bodies
33.
Nucleus pulposus in intervertebral disk
34.
Neural Crest forms Sphenoid bone, squamous portion of temporal bone, frontal, mandible, etc.
35.
Paraxial Mesoderm
Embryology II: Neurulation/Skeletal System Study Aid
8/6/2010 Nickalus Khan
36.
dermis of skin
37.
muscles of the region and retain segmental innervation
38.
Spina Bifida (can be spina bifida occulta (just no fusion of vertebra), s. bifida meningocele (with
meninges protruding, s. bifida meningomyelocele (with spinal cord and meninges)
39.
Tuft of hair covering lesion, increased AFP and AchEsterase
40.
Arnold Chiari malformation (most likely not testable, is tested on boards)
A. Blocks CSF flow
41.
Failure of spinal cord to form
42.
Anencephaly
43.
Exposes brain to amniotic fluid which destroys brain, increased amnion fluid (polyhydramnios
since fetus can’t swallow fluid), increased AFP (remember Alpha feto protein is fetal albumin)
44.
Epimere
45.
Gives rise to muscle with thoracic, lateral and medial abdominal wall (muscles of trunk), some of
hypomere forms limb muscles
46.
Parietal mesoderm
47.
Ectodermal ridge
48.
Forearm then hands and humerus
49.
lateral plate mesoderm (recall parietal and visceral portions of lateral plate mesoderm)
50.
Apoptosis (programmed cell death ), syndactyly
51.
Amelia,melomelia respectively (recall thalidomide disaster that caused this)
52.
Serous lining of peritoneal, pericardial, and pleural membranes and
53.
Cardiac and Smooth muscle
54.
See below
A. Skeletal system is all from mesoderm
B. Sclerotome, Somite= bones of axial skeleton, cranial vault
C. Somatic layer of lateral plate mesoderm=bones of shoulder, pelvic girdle and limbs
D. Neural crest= bones of face
End of Class Quiz Questions
55.
The developing neural tube and the amnion
56.
Neural crest cells
57.
Sclerotomes
58.
Third ventricle
59.
Lateral plate
60.
Sensory and motor