Development of the Limbs Flashcards

1
Q

When do digits start forming

A

8th week

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

When does 1 ossification occur

A

12th week

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

Cartilage, connective tissue and bone of limbs come from

A

Somatic mesoderm

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

Development of limbs proceeds in what direction

A

Proximodistally

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

Stylopod

A

Humerus and femur

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

Zeugopod

A

Radius/ulna and tibia/fibula

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

Autopod

A

Carpels, metacarpals, digits and tarsals, metatarsals

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

Week 5 developments

A

Hand and foot plates

Chondrification center appears

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

Week 6 developments

A

Digital ray of hands

Entire limb skeleton is cartilagenous

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

Week 7 developments

A

Digital rays of feet
Osteogenesis of long bones begins
Rotation of limbs

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

Week 8 developments

A

Separate digits are formed

Apoptosis

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

When do motor axons from spinal cord enter limbs

A

5th week

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

How do sensory axons find their way to limbs

A

They follow motor axons

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

Where do schwann cells come from

A

Neural crest cells

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

Primary axial artery becomes

A

Brachial artery in upper limb or deep artery of thigh

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

Talipes Equinovarus

A

Club foot
Most common musculoskeletal defect
Sole of foot turned medially and inverted
More frequent in males

17
Q

Developmental hip dysplasia

A

More common in females
Underdevelopment of acetabulum of hip bone
Generalized joint laxity

18
Q

Positioning of limbs is regulated by

A

Hox genes

19
Q

Scapula, humerus, radius/ulna, carpals, metacarpals positioned by which hox genes

A
Scapula-9
Humerus-10
Radius/ulna-11
Carpals-12
Metacarpals-13
20
Q

Apical ectodermal ridge proceeds in which way and relies on what signal

A

Proceeds from proximal to distal and depends on FGF signaling

21
Q

Ventral surface is maintained by what signal and dorsal surface maintained by what signal? What do these signals set up

A

Dorsal/extensors by Wnt7
Ventral/flexors by BMPS
These signals set up the apical ectodermal ridge AER

22
Q

Anterior posterior patterning is set up by what, and what signal is involved

A

Zone of polarizing activity on posterior side of limb

Shh signaling from ZPA specifically signals posterior elements

23
Q

Loss of ZPA results in

A

Loss of posterior elements

24
Q

Upregulation of ZPA results in

A

Additional posterior elements (polydactyly)

25
Q

Duplication of ZPA results in

A

Duplication of posterior elements (ex. little fingers on both sides of the thumb)

26
Q

Posterior element formation vs anterior element formation in time

A

Posterior (little finger/ulna) are formed prior to anterior (radius/thumb)

27
Q

Arthrogryposis

A

Congenital joint contractures
Usually involves more than one joint
Thought to be due to neurological defects, muscular abnormalities, joint and contiguous tissue problems, fetal crowding