Lecture 4- Embryology

Question 1

What are the 3 layers of the trilaminar disc formed during the 3rd week of development?

Answer 1

Ectoderm
Mesoderm
Endoderm

Question 2

What induces the ectoderm to form the neural plate?

Answer 2

Factors from the paraxial mesoderm and notochord induce the ectoderm to form the neural plate/neural ectoderm

Question 3

What is neuralation? When does it occur?

Answer 3

Neuralation is the process by which the neural plate forms a neural tube. It occurs during the 3rd week of development and concludes w/the closing of the neuropores

Question 4

When do the neuropores close?

Answer 4

4th week of development

Question 5

What are the cells that inhabit the peak of the neural fold refer to as?

Answer 5

neural crest cells inhabit the peak of the neural fold

Question 6

What does the lumen of the neural tube give rise to?

Answer 6

the ventricular system of the brain and the central canal of the spinal cord

Question 7

What does incomplete closure of the dorsal neuropore result in?

Answer 7

spina bifida

Question 8

What is spina bifida oculta?

Answer 8

Caused by incomplete closure of the caudal neuropore during development results in vertebral arches that fail to fuse int he lumbosacral region. Usually asymmptomatic except for a tuft of hair over the affected area.

Question 9

What is spina bifida cystica?

Answer 9

Caused by an incomplete closure of the caudal neuropore resulting in vertebral arches that fail to fuse and neural tissue and meninges may protrude through the defect.

Question 10

What results from an error in the closing of the rostral neuropore?

Answer 10

anencephaly

Question 11

What develops from the alar plate?

Answer 11

Dorsal horn/Sensory

Question 12

What develops from the basal plate?

Answer 12

Ventral horn/Motor

Question 13

What does the ventricular zone give rise to in adults?

Answer 13

ependymal layer lining the ventricles and central canal

Question 14

What does the marginal zone become in the spinal cord?

Answer 14

white matter

Question 15

What does the mantle zone become in the spinal cord?

Answer 15

gray matter

Question 16

What is the fictional division between the dorsal and ventral portions of the spinal cord?

Answer 16

Sulcus limitans

Question 17

What develops from the sclerotome of the somite?

Answer 17

skeleton and cartilage

Question 18

What develops from the myotome of the somite?

Answer 18

muscle

Question 19

What develops from the dermatome of the somite?

Answer 19

dermis of the skin

Question 20

What does the dorsal root ganglion develop from?

Answer 20

neural crest cells

Question 21

What are the 3 parts in the initial 3 vesicle stage?

Answer 21

prosencephalon (forebrain)
mesencephalon (midbrain)
rhombencephalon (hindbrain)

Question 22

What two structures develop from the prosencephalon?

Answer 22

Telencephalon

Diencephalon

Question 23

What two structures develop from the rhombencephalon?

Answer 23

metencephalon

myelencephalon

Question 24

What two flexures develop during the 3 vesicle stage?

Answer 24

mesencephalic flexure

cervical flexure

Question 25

What flexure develops during the 5 vesicle stage?

Answer 25

pontine flexure

Question 26

Which flexure persists into adulthood?

Answer 26

cephalic (cervical?)

Question 27

What do neural crest cells develop?

Answer 27

sensory and parasympathetic ganglia
cartilage and bone
CT
Endocrine cells
melanocytes
Dorsal root ganglia
PNS supportive cells

Question 28

What causes the walls of the neural tube to splay laterally in the brain stem region?

Answer 28

pontine flexure