Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

ANAT 381 Experimental Embryology > Limb Development and Disrupting Embryonic Development > Flashcards

Limb Development and Disrupting Embryonic Development Flashcards

1
Q

Each of the following limb development regions is responsible for which part?
a. Stylopod
b. Zeugopod
c. Autopod

A

a. Humerus
b. Ulna and radius
c. Carpals and digits

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What are the critical regions in the developing limb bud?

A

Progress zone, zone of polarizing activity (ZPA), apical ectodermal ridge (AER)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Where is the ZPA located?

A

Posterior mesenchyme of the limb bud

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Where is the AER located?

A

At the boundary of dorsal and ventral sides of the limb bud

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

AER is required for patterning which axes of the limb bud?

A

Proximal-distal, dorsal-ventral, anterior-posterior

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What can replace the AER activity?

A

Implantation of FGF bead

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

RA concentration is higher on the __________ axis and Fgf/Wnt concentration is higher on the ___________ axis

A

Proximal; distal

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Which genes are linked to the stylopod, zeugopod and autopod?

A

Meis for stylopod, Hox11 for zeugopod and Hox13 for autopod

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What is RA responsible for in limb bud PD patterning?

A

RA activates Meis genes and promotes proximal formation of the limb bud

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What is FGF/Wnt responsible for in limb bud PD patterning?

A

FGF initiates Hox13 genes and promotes distal formation of the limb bud

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Hoxa11/Hoxd11-deficient mice are missing which limb part?

A

Zeugopod

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

In humans, homozygous mutation in Hoxd13 causes which disorder?

A

Polysyndactyly (fused digits)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What does AER activity require?

A

Limb bud mesenchyme

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

PD specification of the limb is correlated with what factor?

A

The age of the progress zone mesenchyme

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

___________ and ___________ is expressed in dorsal ectoderm, ___________ is expressed in ventral ectoderm

A

Wnt7a; Lmx1; En-1

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

A loss of Lmx1 causes what effect?

A

Ventralized dorsal side, causing two ventral sides

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

Knockout of Engrailed causes what effect on the limb?

A

Loss of ventral patterning

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

Addition of AER tissue to the forelimb mesenchyme causes what effect?

A

Digit duplication

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

ZPA transplantation of mouse ZPA to chick causes what effect?

A

Formation of digits

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

What is expressed in ZPA?`

A

Shh

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

Transplanting ZPA of Shh beads causes what effect?

A

Mirror image duplication

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

Identify the response to Shh signaling to the digits
a. Shh independent
b. Differentiation dependent on Shh concentration (paracrine)
c. Shh-dependent; time-dependent (autocrine)

A

a. Digit 1
b. Digits 2 and 3
c. Digits 4 and 5

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

(Fgf8/Shh) is expressed in the ZPA after (Fgf8/Shh) is expressed in the AER

A

Shh; Fgf8

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

What is the mechanism of FGF activating Shh with the activity of Grem1?

A

Grem1 stimulates FGF when FGF is low
High FGF stimulates Shh expression and represses Grem1 activity
Low Grem1 activity decreases FGF expression

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

What determines limb identity?

A

Limb mesenchyme

26
Q

Tbx5 is expressed in which limb?

A

Wing limb

27
Q

Tbx6 is expressed in which limb?

A

Leg limb

28
Q

Early knockout of Tbx5 causes what effect?

A

Forelimbs do not develop

29
Q

Later knockout of Tbx5 after E9.5 causes what effect?

A

Forelimbs develop normally

30
Q

What happens if Tbx5 is knocked out and replaced with Tbx4 or Pitx1?

A

Ectopic Tbx4 in forelimb bud led to normal development of forelimb
Ectopic Pitx1 in forelimb bud led to no forelimb development

31
Q

Tbx4/5 are required for forelimb/hindlimb bud _________, but not identity

A

Initiation

32
Q

Pitx1 is important for the _____________ bud development

A

Hindlimb

33
Q

Every _______ minutes, there is a baby born in the US with a birth defect

A

4.5

34
Q

What is the percentage of human cleavage-stage embryos implanting?

A

20-50%

35
Q

What is the percentage of the survival of embryos that implant?

A

40%

36
Q

What is the percentage of live births that have a recognizable birth defect?

A

2.5%

37
Q

Congenital anomalies account for what percentage of annual neonatal deaths?

A

9%

38
Q

Identify the description to either embryo or fetus
a. First 8 weeks in humans
b. Weeks 9-40 in humans
c. Period of development during which the organism does not resemble the adult
d. Growth and refinement

A

a. Embryo
b. Fetus
c. Embryo
d. Fetus

39
Q

When is the risk of defects highest?

A

Organogenesis

40
Q

What are the periods of sensitivity for abnormal development in the CNS, upper and lower limbs?

A

CNS: Weeks 3 to full term
Upper and lower limbs: Weeks 4 1/2 to 9

41
Q

What is genetic heterogeneity?

A

Similar phenotypes caused by different genes

42
Q

What is phenotypic heterogeneity?

A

Same mutation causes different phenotypes in different individuals

43
Q

What are some causes of congenital anomalies/birth defects?

A

Genetic factors, environmental factors, stochastic factors

44
Q

Dysplasia is an abnormal organization of cells into ___________ and its morphological result

A

Tissues

45
Q

Deformations are caused by what factors?

A

Mechanical forces or physical environment

46
Q

Malformations are caused by what factor?

A

Intrinsically abnormal development process

47
Q

Disruptions are caused by what factor?

A

Interference of an originally normal process

48
Q

Clubfoot is potentially caused by _____________

A

Oligohydraminos

49
Q

What is the name of the limb malformation caused by a mutation in Tbx5 and characterized by upper limb anomalies?

A

Holt-Oram Syndrome

50
Q

Which drug was used to treat influenza, as a sedative and to treat nausea and vomiting during pregnancy?

A

Thalidomide

51
Q

What limb disruption is caused by the use of Thalidomide?

A

Upper limb anomalies

52
Q

Limb disruptions occur _________ during limb development and limb deformations occur ____________ during limb development

A

Early; later

53
Q

What is an agent that affects morphogenesis, development and differentiation through cell death, failed cell interactions or alterations of cell movements?

A

Teratogen

54
Q

What are 3 considerations of teratogens?

A

Critical periods of development, dosage of the drug and genotype of the embryo

55
Q

What are other teratogens that exist?

A

Isotretinoin, alcohol, endocrine disruptors, Rubella virus

56
Q

How are the effects of thalidomide tested?

A

Testing of drugs in pregnant experimental animals

57
Q

What is the syndrome caused by fetal exposure to alcohol?

A

Fetal alcohol syndrome

58
Q

What are the symptoms of fetal alcohol syndrome?

A

Poor growth, decreased muscle tone and poor contraction, delayed development and problems in thinking, speech, movement or social skills

59
Q

What are the phenotypes of ethanol-induced dysmorphology?

A

FAS, HPE, HPE plus cleft lip

60
Q

Retinoic acid induces _________________

A

Holoprosencephaly (HPE)

61
Q

Hydrocephaly, microcephaly and increased risk of spontaneous abortions are congenital anomalies caused by ______________

A

Isotretinoin

62
Q

What were the goals of the iPLEDGE program?

A

Ensure that no pregnant woman starts taking Isotretinoin and no woman taking Isotretinoin becomes pregnant

ANAT 381 Experimental Embryology (24 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions