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Flashcards in Development of the Musculoskeletal System Deck (65)
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1
Q

What is included in the axial skeletal system?

A

Ribs, vertebra, sternum, and skull

2
Q

What is included in the appendicular skeleton?

A

Pectoral girdle, pelvic girdle, and limb bones

3
Q

What are the two divisions of mesoderm that the skeletal system is derived from?

A

Paraxial mesoderm (somites), and lateral plate somatic mesoderm

4
Q

Paraxial mesoderm differentiates into what?

A

Mesenchyme then vertebral column, ribs, and neurocranium

5
Q

Lateral plate somatic mesoderm differentiates into what?

A

Mesenchyme then pectoral girdle, pelvic girdle, ribs, and sternum (appendicular skeleton)

6
Q

Neural crest cells differentiates i

A

Mesenchyme then viscerocranium and hyoid bone

7
Q

What is all of the axial skeleton derived from, except what exception?

A

Sclerotome forms all of the axial skeleton except the sternum and a portion of the skull

8
Q

The nucleus pulposus is derived from what?

A

The notocord

9
Q

At the fourth week of development the sclerotome cells do what?

A

Surround the neural tube and notocord

10
Q

How are each sclerotomes divided?

A

A less dense cranial portion and a dense caudal portion

11
Q

The dense portion of the sclerotome form what?

A

Annulous fibrosus of IV discs

12
Q

The dense portion of a sclerotome fuses with what structure to form what?

A

The less dense portion of the sclerotome immediately inferior to form the vertebral body

13
Q

When does chondrification of the vertebral bodies occur?

A

6th week

14
Q

When does ossification of vertebral bodies begin?

A

7th week

15
Q

When do vertebral arch halves fuse?

A

3-5 years

16
Q

When does the vertebral arch fuse with the body?

A

3-6 years

17
Q

When is ossification of vertebral bodies complete?

A

About 25 years

18
Q

The sclerotome differentiates into what that will become the annulous fibrosus?

A

Intersegmental mesenchyme

19
Q

The sternum starts off as what two things that will fuse cranial to caudal?

A

Sternal bars

20
Q

What is the neurocranium?

A

Bones that encase the brain

21
Q

Where is the viscerocranium?

A

Anterolateral facial bones

22
Q

What parts of the skull are formed by endochondral ossification?

A

Sphenoid, petrous portion of temporal bone, portion of occipital bone

23
Q

How is the rest of the skull formed that does not develop from endochondral ossification?

A

Intramembranous ossificaiton

24
Q

Intramembranous ossification forms what kind of bones that surround the brain?

A

Flat bones

25
Q

Where is the cartilaginous neurocranium?

A

Base of the skull

26
Q

Where is the membranous neurocranium?

A

Flat bones that surround the brain

27
Q

The bregma takes place of what in a newborn?

A

The anterior fontanelle

28
Q

The pterion takes place of what in a newborn?

A

Anterolateral or sphenoidal fontanelle

29
Q

The lambda takes place of what in a newborn?

A

Posterior fontanelle

30
Q

What fontanelle in a newborn does not have a special name that takes its place?

A

Posteriolateral or mastoid fontanelle

31
Q

When does ossification of long bones begin?

A

7/8th week

32
Q

Skeletal muscle is derived from what?

A

Paraxial mesoderm

33
Q

Cardiac muscle is derived from what?

A

Intraembryonic splanchnic mesoderm surrounding developing heart

34
Q

Smooth muscle of the GI tract is derived from what?

A

Intraembryonic splanchnic mesoderm surrounding gut tube

35
Q

Somites give rise to what?

A

Axial skeleton (most), Associated musculature, Overlying dermis of back

36
Q

Somites differentiate into what three initial things?

A

Sclerotome, myotome, and dermatome

37
Q

What are myoblasts?

A

Specialized mesoderm cells that fuse together to form skeletal muscle and can actively contract by week seven

38
Q

Progenitor cells for muscle tissues derived from the 1)________ and 2)________ lips of the 3)________

A

1) Ventrolateral
2) Dorsalmedial
3) Dermomyotome

39
Q

What separates the paraxial mesoderm from lateral plate somatic mesoderm?

A

Lateral somitic frontier

40
Q

What domain surrounds neural tube and contains only somite-derived cells?

A

Primaxial domain

41
Q

What domain is the parietal layer of lateral plate mesodem with somite-derived cells

A

Abaxial domain

42
Q

The ventrolateral lip cells left at the myotome will form what?

A

Musculature of the back, Shoulder girdle muscles, Intercostal muscles

43
Q

Most Ventrolateral lip (VLL) myoblasts migrate across the frontier into lateral plate somatic mesoderm to form what?

A

Infrahyoid muscles, Pectoralis major & minor muscles, Abdominal wall muscles, and Limb muscles

44
Q

Each myotome divides into what two things?

A

Epaxial group (dorsal/posterior)(back) and hypaxial group (ventral/anterior)(includes limbs)

45
Q

Each spinal nerve divides into what two things?

A

Dorsal primary ramus and ventral primary ramus

46
Q

The sphincter pupillae m. and dilator pupillae m. of the iris are developed from what?

A

Neuroectoderm

47
Q

Myoepithelial cells of mammary, salivary, & sweat glands are derived from what?

A

Surface ectoderm

48
Q

Limb buds emerge around the end of what week?

A

4th

49
Q

Do upper or lower limbs develop first?

A

Upper followed by lower 1-2 days later

50
Q

What is the distal most end of a developing limb called?

A

Apical ectodermal ridge (AER)

51
Q

Just proximal to the AER is what zone of the developing limb?

A

Progress zone

52
Q

Melanocytes of the developing limb come from what?

A

Neural crest

53
Q

Sensory axons and Schwann cells of the developing limb come from what?

A

Neural crest

54
Q

Myoblasts of the developing limb come from what?

A

From myotome of VLL

55
Q

Motor axons of the developing limb come from what?

A

From neural tube

56
Q

When does limb rotation occur?

A

Week seven

57
Q

How do the upper limbs developmentally rotate?

A

Lateral rotation of 90 degrees

58
Q

How do the lower limbs developmentally rotate?

A

Medial rotation of 90 degrees

59
Q

When is the paddle stage of limb development?

A

6th week

60
Q

What are digital rays?

A

Outlines of future digits

61
Q

When will a fetus have fully developed digits?

A

End of eighth week

62
Q

What is meromelia?

A

Absence of part of a limb

63
Q

What is amelia?

A

Absence of an entire limb (absence of AER)

64
Q

What is polydactyly?

A

Extra digits

65
Q

What is syndactyly?

A

Two or more fused digits