Neurulation & Neural Crest

Question 1

gastrulation

Answer 1

the formation of the 3 primary germ layers

Question 2

3 parts of the primitive streak

Answer 2

primitive knot
primitive groove
primitive pit

Question 3

the neural plate will form the ______ by releasing ____

Answer 3

central nervous system

sonic hedgehog

Question 4

somites

Answer 4

come from the paraxial mesoderm

- form the myotome, sclerotome, and dermatome

Question 5

intermediate mesoderm becomes the

Answer 5

urogenital system including kidneys and gonads, ducts, and accessory glands

Question 6

lateral plate mesoderm becomes ____

Answer 6

connective tissue

• blood
• lymph
• mesenteries
• cardiovascular

Question 7

surface ectoderm becomes

Answer 7

hair, skin, nails, mammary glands, teeth enamel, internal ear, lens of eye

Question 8

primary neurulation

Answer 8

the neural plate folds in and closes; the closing of the rostral neuropore

• occurs at around day 25
• closure of brain, cervical, thoracic, and lumbar portions of spinal cord

Question 9

secondary neurulation

Answer 9

caudal eminence fuses with posterior neuropore to form the sacral and coccyx part of the spinal cord
- hollow tube is formed

Question 10

neural crest cells

Answer 10

found in the cranial and trunk regions; give rise to sensory neurons only

• spinal ganglia
• autonomic ganglia
• cranial nerves 5, 7, 9, 10

Question 11

neurilemma

Answer 11

supporting cells arising from the neural crest; the schwann cels; they myelinate the neurons in the peripheral nervous system

Question 12

leptomeninges

Answer 12

supporting cells arising from the neural crest; the pia and dura mater

Question 13

ectomesenchyme

Answer 13

arises from neural crest

• bone and cartilage of facial skeleton
• walls of large arteries from aortic arches
• enamel and dentin

Question 14

Hirschsprung’s disease

Answer 14

type of trunk neural crest defect; megacolon - autonomic system does not innervate the colon so infants cannot defecate

Question 15

aorticopulmonary septation defects of the heart can be caused by what neural crest defect

Answer 15

cranial

Question 16

cleft lip and/or cleft palate can be caused by what neural crest defect

Answer 16

cranial

Question 17

DiGeorge syndrome

Answer 17

type of cranial neural crest defect
- hypoparathyroidism, thyroid deficiency, thymic dysplasia leading to immunodeficiency, defects in cardiac outflow tract and aortic arches

Question 18

dental anomalies can be caused by what neural crest defect

Answer 18

cranial

Question 19

neuroblastoma

• what is it
• what neural crest defect causes it

Answer 19

tumor of adrenal medulla and/or autonomic ganglia

proliferation defects

Question 20

what embryological event can cause albinism

Answer 20

neural crest defect

Question 21

alpha fetal protein

Answer 21

shown to be increased in cases of meningocele, meningomyelocele, and myelocele; indicative of neural tube defects
- can use amniocentesis to test for this

Question 22

what supplement can prevent neural tube defects

Answer 22

folic acid

Question 23

spina bifida occulta

Answer 23

caused by the caudal neural pore not closing properly; results in a gap between spinous processes and sometimes a tuft of hair on the lower back and/or a dimple
- patients are normal

Question 24

meningocele

Answer 24

caudal neural pore closed but there are not vertebral arches or neural arches; causes a CSF filled cyst on the meninges that can be surgically repaired; spinal cord is NOT located in the cyst

Question 25

meningomyelocele

Answer 25

caudal neural pore closure defect; patients have a cyst on the spinal cord that DOES contain the meninges and spinal cord - sensory and motor defects

Question 26

myelocele

Answer 26

caudal neural pore did not close and the spinal cord is exposed; surgically corrected after birth; motor and sensory defects

Question 27

Anencephaly

Answer 27

patients are missing the bony covering of the skull and part of the brain; incompatible with life; brain stem is intact and there is normal respiratory and cardiac function - patients at risk for infection

Question 28

encephalocele (with brain tissue)

Answer 28

neural tube defect characterized by sac-like protrusions of the brain and the membranes that cover it through openings in the skull; defects are caused by failure of the neural tube to close completely during fetal development. - mental and physical deficits

Question 29

encephalocele (without brain tissue)

Answer 29

neural tube defect with sac-like protrusions that do NOT contain brain material and the patients are usually normal; caused by failure of the neural tube to close completely in development

Question 30

when is the rostral tube closure finished

Answer 30

day 28

Question 31

what do the meninges develop from

Answer 31

meninx primitiva

Question 32

meninx primitiva

Answer 32

mesoderm in origin; derived from sclerotome; contains some neural crest cells that have migrated in - divides into pachymenix and leptomeninges

Question 33

pachymeninx

Answer 33

the dura mater; derived from mesoderm portion of the meninx primitiva

Question 34

leptomeninges

Answer 34

the arachnoid and pia mater; derived from the neural crest cells of the meninx primitiva

Question 35

the meninx primitiva divides into two cell populations called:

Answer 35

pachymeninx (dura mater) | leptomeninges (arachnoid and pia mater)

Question 36

paraxial mesoderm forms:

Answer 36

muscles of head, striated skeletal muscle (trunk, limbs), skeleton except cranium, dermis of skin, connective tissue

Question 37

lateral mesoderm forms:

Answer 37

connective tissue and muscle of viscera, primordial heart, spleen, blood and lymphatic cells, adrenal cortex

Question 38

neuroectoderm forms what two main branches

Answer 38

neural crest and neural tube

Question 39

neural crest forms

Answer 39

- cranial and sensory ganglia and nerves - medulla of suprarenal gland - pigment cells - pharyngeal arch of cartilages - head mesenchyme and connective tissue - bulbar and conal ridges in heart

Question 40

neural tube forms

Answer 40

- central nervous system - retina - pineal body - posterior part of pituitary gland

Question 41

Endoderm from the trilaminar embryonic disc forms

Answer 41

- Epithelial parts of (pharynx, thyroid gland, tympanic cavity, pharyngotympanic tube, so tilts, parathyroid glands) - epithelium of (GI tract, liver, pancreas, urinary bladder, urachus) - epithelial parts of (trachea, bronchi, lungs)

Question 42

When are the upper limb bud, lower limb bud, primordial of lens, and the fourth pharyngeal arch formed by

Answer 42

Week 4