Brainscape's Knowledge GenomeTM

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


See full index

Structures: Part Deux > LEC41: Early Limb Development and the Musculoskeletal System > Flashcards

LEC41: Early Limb Development and the Musculoskeletal System Flashcards

1
Q

where does limb development begin?

A

upper extremity

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

when does limb development begin?

A

end of week 3 - when heart starting to beat

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

when do upper limb buds appear?

A

day 26-27

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

when do lower limb buds appear?

A

day 28-29

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

what do limb buds develop from?

A

proliferation of somatic layer of lateral mesoderm into surface ectoderm

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

where do upper extremities form?

A

cervical region of embryo

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

where do lower extremities form?

A

lumbar/sacral region of embryo

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

how does AER form

A

apical ectodermal ridge, formed by mesenchyme pushing into ectoderm, induces it to thicken at apex

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

what is AER

A

dense ridge of tissue that’ll form the limb

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

function of SHH

A

sonic hedgehog tissue factor - differentiates limb bud from symmetrical structure to distinct fingers

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

how does SHH work

A

gradient across mesenchymal growth area; most dense in zone of polarizing activity which gives hands diff poles

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

without SHH how would hand appear?

A

paddle, no fingers

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

what is zone behind AER called?

A

progress zone

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

function of progress zone

A

proliferates rapidly, causing mechanical growth of AER

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

what does AER induce

A

tissue, transcription factors to feed back on mesodermal core (mesenchyme) and become musculoskeletal (bone, muscle) components

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

when does upper limb > hand develop

A

finished by end of week 6

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

how do fingers form

A

apoptosis in region of upper limb paddle

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

digital rays

A

outgrowths from hand/foot paddles that become fingers, toes; each has AER (apical ecotodermal ridge, growth area) at its tip

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

when do foot plates finish forming

A

week 7

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

how do toes for m

A

apoptosis in region of lower limb paddle

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

what is endochondral ossification

A

mesenchyme remodels into cartilage remodels into bone

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

when does bone ossification occur

A

begins week 7, finishes after birth

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

end of week 6, what is make up of limb skeleton?

A

all cartilage

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

where is growth plate of long bone?

A

epiphyseal cartilage plate

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

where in bone does primary ossification occur?

A

diathesis

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

what is direction of bone ossification?

A

primary ossification in diathesis; bone grows toward secondary ossification centers at ends of bone, the growth plates

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q

how can you visualize ossification centers

A

ultrasound

28
Q

when and how does growth plate become obliterated?

A

at/after puberty; diaphysis-epiphysis fuse, long bone growth stops (or earlier if have something like radiation)

29
Q

limb muscle muscle type

A

skeletal, for movement

30
Q

what are somites derived from

A

paraxial mesoderm laid down during gastrulation, right next to notochord

31
Q

what do somites differentiate into?

A

dermomyotome, sclerotome

32
Q

what do dermomyotomes become

A

dermatomes (dermis), myotomes (muscle)

33
Q

what do sclerotomes become?

A

vertebrae, ribs

34
Q

which somite derivative is more dense?

A

dermomyotome (outer layer) is more dense than sclerotome (inner layer)

35
Q

what are myoblasts, where are they derived from?

A

from myotome region of somites; give rise to muscle fibers

36
Q

what do neural crest cells become?

A

pigment cells (melanocytes), nerve sheaths, insulators

37
Q

what migrates to end of limb bud/hand?

A

myogenic precursors from myotomes & major blood vessels, nerves, muscle fibers (flexors, extensors)

38
Q

what do myoblasts form from

A

myogenic precursors

39
Q

which muscle compartment forms from aggregate of dorsal myloblasts

A

extensor

40
Q

which muscle compartment forms from aggregate of ventral myloblasts

A

flexor

41
Q

how do muscles elongate

A

as limb grows outward

42
Q

what does limb bud mesenchyme give rise to?

A

loose CT > tendons, ligaments, blood vessels that attach to bone

43
Q

what controls limb muscles

A

motor nerve axons, arise from spinal cord; grow into both dorsal and ventral muscle masses

44
Q

when does motor innervation of limbs occur

A

week 5

45
Q

what provides cutaneous innervation of the limbs?

A

neural crest cells

46
Q

which nerves mostly supply cutaneous innervation of upper limb?

A

C6, 7, 8

47
Q

spinal cord transsection where would allow upper limbs to still work?

A

C8-T1

48
Q

what nerve root values mostly involved with lower extremity?

A

L3, 4, 5

49
Q

what is root value for dermatomal innervation for anterior aspect for arm?

A

T1, T2

50
Q

how do upper limbs rotate, what is the result?

A

laterally 90o; elbow becomes dorsal

51
Q

how do lower limbs rotate, what is the result?

A

medially 90o, knee becomes ventral

52
Q

when did thalidomide impact embryo

A

critical period of limb development, days 24-36

53
Q

process by which vertebral column forms?

A

endochondral ossification: mesenchymal models of vertebrae made; transform into cartilage; cartilage, w/ osteoplasts & osteoblasts, become ossified, elongated bone

54
Q

what makes bony encasement of spinal cord, and when?

A

sclerotomes from somites surround neural tube; embryonic week 4-5

55
Q

what occurs during mesenchymal stage of vertebral development?

A

sclerotomal cells “migrate to”

1) notocord
2) neural tube
3) body wall

56
Q

what is centrome, how does it form?

A

body of vertebra, neural arches on sides of vertebral bodies; forms when cranial portion of 1 sclerotome joins w/ caudal portion of adjacent sclerotome

57
Q

action of intersegmental nerves?

A

grow between 2 portions of sclerotomes, toward myotomes

58
Q

what does centrum formation create?

A

space for intervertebral disc

59
Q

hypaxial dermomyotome becomes

A

flexor muscles

60
Q

epaxial dermomyotome becomes

A

extensor muscles

61
Q

what happens to notochord during vertebral development?

A

degenerates within vertebral bodies; forms nucleus pulposis of IV discs

62
Q

when and where are chondrification centers re: vertebral development?

A

week 6

formation of cartilagenous vertebral column

63
Q

when is cartilaginous stage of vertebral development?

A

week 6

64
Q

when is bony stage of vertebral development?

A

week 7

65
Q

where are ossification centers during bony stage of vertebral development?

A

3 primary ossification centers in vertebra:

1) body of vertebra
2) 1 in each neural arch, to 2 others

continue to ossify until age 25 - long bones to grow!

66
Q

what is kyphoscoliosis

A

when sclerotomes split and nerves grow between, one of them doesn’t split correctly or disproportionate split, etc. - anything to make hemivertebrae not form - get klyphoscholiosis of the spine

67
Q

what causes kyphoscoliosis

A

hemivertebra (1 or more)

Structures: Part Deux (36 decks)

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