Embry 2 Flashcards

1
Q

What are the 3 roles of the notochord

A
  1. establishes the longitudinal axis of the embryo and gives it some rigidity
  2. provides signals for the development of axial MSK structures and the CNS
  3. contributes to the intervertebral discs
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2
Q

mesenchymal cells dive into the primitive pit and migrate cephalad, they form a cord called what?

A

notochordal process

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3
Q

the notochordal process develops a lumen known as the ?

A

notochordal canal

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4
Q

after the notochordal process approaches the prechordal plate, the floor of the process “fuses” with the ?. The notochordal process is now the ?

A

endoderm
notochordal plate

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5
Q

notochordal plate -> notochord transition starts

A

cranially and progresses caudally

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6
Q

the notochord induce the overlying ectoderm to develop into the ?

A

neural plate

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7
Q

the prechordal plate develops into the ?

A

oropharyngeal membrane

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8
Q

the oropharyngeal membrane has how many layer membrane?

A

ectoderm and endoderm, no mesoderm

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9
Q

What forms caudal to the primitive streak

A

cloacal membrane

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10
Q

how many layers are in the cloacal membrane?

A

two layers - ectoderm and endoderm, no mesoderm

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11
Q

what is the future site of the anus

A

cloacal membrane

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12
Q

what is allantois and what does it do?

A

small, vascularized diverticulum from the caudal wall of umbilical vesicle, extending into the connecting stalk
- functions in early blood formation and bladder develop, blood vessels become umbilical arteries

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13
Q

notochord induces overlying ectoderm to form the ?

A

neural plate also known as neuroectoderm

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14
Q

on day 18, the neural plate invaginates to form ?

A

the neural groove - neural folds are found on either side of the groove

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15
Q

the neural folds eventually fuse together, and form the ?

A

neural tube

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16
Q

what is neurulation

A

the process by which the neural tube is formed

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17
Q

True or False: during the 3rd week, intraembryonic mesoderm proliferates to form a thick column of mesoderm on either side of the notochord

A

true

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18
Q

what is paraxial mesoderm

A

right beside the notochord

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19
Q

where is the intermediate mesoderm

A

just lateral to the paraxial mesoderm

20
Q

where is the lateral mesoderm

A

lateral to the intermediate mesoderm

21
Q

what are somites?

A

cuboidal masses of mesoderm on either side of the notochord, visible along the dorso-lateral surface of the embryo on each side of the neural tube, formed from the paraxial mesoderm

22
Q

during the 3rd week mesenchymal cells migrate anteriorly, lateral to the notochordal process to eventually form what?

A

cardiogenic mesoderm

23
Q

the primordium of the intraembryonic coelom (embryonic body cavity) appears where?

A

isolated spaces in the lateral mesoderm and cardiogenic mesoderm

24
Q

intra-embryonic coelom divides the lateral mesoderm into 2 layers which are?

A
  • somatic or parietal layer of lateral mesoderm located beneath the ectodermal epithelium and continuous with the extraembryonic mesoderm
  • splanchnic or visceral layer of lateral mesoderm next to the endoderm and continuous with the extraembryonic mesoderm covering the umbilical vesicle
25
Q

3 general structures in the region of the lateral mesoderm:

A
  • somatopleure
  • splanchnopleure
  • intraembryonic coelom in between the somatopleure and splanchnopleure
26
Q

what is the somatopleure and where is it?

A

the somatic mesoderm and the overlying ectoderm, forms the body wall

27
Q

what is the splanchnopleure and where is it?

A

the splanchnnic mesoderm and the underlying intraembryonic endoderm, forms the embryonic gut

28
Q

during the 2nd month, the intraembryonic coelom develops into 3 main body cavities which are:

A
  • pericardial cavity
  • pleural cavity
  • peritoneal cavity
29
Q

what is embryonic folding

A

the process by which a relatively “flat” embryonic disk becomes more and more cylindrical in shape

30
Q

folding occurs in 2 general planes which are?

A

the median plane and horizontal plane

31
Q

describe embryonic folding in the median plane

A

anterior and posterior ends of the embryo move ventrally

32
Q

median plane is also known as?

A

cranial-caudal folding

33
Q

describe embryonic folding in the horizontal plane

A

the lateral edges of the embryonic disk move ventrally

34
Q

the horizontal plane is also known as ?

A

lateral folding

35
Q

what is the primordium of the mouth

A

stomodeum

36
Q

the position of the heart changes due to what?

A

the head fold

37
Q

lateral folding is caused by the rapidly growing what?

A

spinal cord and somites

38
Q

what are the 3 germ layers?

A
  • ectoderm
  • mesoderm
  • endoderm
39
Q

the neural plate can been seen at what day?

A

day 19

40
Q

what line the central canal of the spinal cord?

A

ependymal cells

41
Q

the alar and basal plates of the developing spinal cord are separated by a groove called?

A

the sulcus limitans

42
Q

cell bodies in the alar plates form what?

A

the dorsal gray horns

43
Q

cell bodies in the basal plates form what?

A

ventral and lateral gray horns

44
Q

the unipolar neurons in the spinal ganglia (dorsal root ganglia) are derived from what?

A

neural crest cells

45
Q

fusion of the neural folds in the cranial region and closure of the rostral neuropore form 3 primary brain vesicles:

A
  • forebrain (prosencephalon)
  • midbrain (mesencephalon)
  • hindbrain (rhombencephalon)
46
Q

during week 5, the prosencephalon partially divides into 2 secondary brain vesicles which are?

A

telencephalon and diencephalon

47
Q

by week 5, the rhombencephalon also partially divides into?

A

metencephalon and myelencephalon