Wid1 - Development Of The Musculoskeletal System

Front 1

Where does the skeletal system develop from?

Back 1

paraxial and lateral plate (somatic layer) mesoderm and neural crest.

Front 2

Paraxial mesoderm forms a segmented series of tissue blocks on each side fo the neural tube, known as ________.

Back 2

somitomeres in the head region and somites from the occipital region caudally.

Front 3

What do somites differentiate into?

Back 3

ventromedial part: the sclerotome
Dorsolateral part: the dermomyotome

Front 4

At the end of the 4th week, sclerotome cells become polymorphous and form a losely woven tissue, the _______. (or embryonic connective tissue)

Back 4

mesenchyme

Front 5

What things does the mesenchyme differentiate into?

Back 5

fibroblasts, chondroblasats, or osteoblasts (bone-forming cells)

Front 6

The bone-forming capacity of mesenchyme is not restricted to cells of the sclerotome but occurs in the _________ mesoderm layer of the body wall, which contributes mesoderm cells for formation of the ______- and _______ girdles and ______ bones of the limbs.

Back 6

somatic, pelvic and shoulder girdles, LONG bones of the limb.

Front 7

Neural Crest cells in the head region also differentiate into ________- and participate in formation of bones of the _____-- and _______.

Back 7

mesenchyme, face and skull

Front 8

Occipital somites and somitomeres also contriubte to formation of the ____________ of the skull.

Back 8

cranial vault and base

Front 9

In some bones, such as the flat bones of the skull, mesenchyme in the dermis differentiates directly into bone, a process known as _______.

Back 9

intramembranous ossification

Front 10

In most bones, however, mesenchymal cells first give rise to _______--- ________ models, which in turn become ossified by ______-- ossification rather than intramembranous ossification.

Back 10

hyaline cartilage, endochondral

Front 11

What do each of these give rise to?
Paraxial mesoderm ->
lateral plate mesoderm (somatic) ->
neural crest ->

Back 11

pm: axial skeletal structures
lat.plate: radial bones
NC: facial bones

Front 12

The skull can be divided into 2 parts: the ______cranium which forms a protective case around the brain, and the ______cranium, which forms the skeleton of the face.

Back 12

neurocranium, viscerocranium

Front 13

The neurocranium is most conveniently divided into 2 portions:

Back 13

membranous part, consisting of flat bones, which surround the brain as a vault, and the cartilaginous part, or chondrocranium, which forms bones of the base of the skull

Front 14

What is the membranous portion of the skull derived from?

Back 14

neural crest cells and paraxial mesoderm

Front 15

mesenchyme from the neural crest cells and paraxial mesoderm undergo ______ ossification to form the membranous portion of the skull.

Back 15

membranous

Front 16

The result of NC cells and paraxial mesoderm undergoing membranous ossification when invested in the skull = formation of a number of ________, - bones that are characterized by the presence of needlelike ______ _______.

Back 16

formation of a number of flat, membranous bones that are characterized by the presence of needlelike bone spicules.

Front 17

The bone spicules found on the membranous bones of the skull progressively ________ from _________-centers toward the periphery.

Back 17

radiate,primary ossification

Front 18

How do membranous bones enlarge during fetal and postnatal life?

Back 18

membranous bones enlarge by apposition of new layers on the outer surface and by simultanenous osteoclastic resorption from the inside.

Front 19

At birth, the flat bones of the skull are separated from each other by narrow seams of connective tissue, called _______.

Back 19

sutures

Front 20

The sutures at birth are formed from two sources which are:
sagittal from _____-
and coronal from _____-

Back 20

sagittal -> NC cells
coronal -> paraxial mesoderm

Front 21

At points where more than two bones meet, sutures are wide and are called ______--

Back 21

fontanelles

Front 22

What is the most prominent fontanelle?

Back 22

anterior fontanelle, which is found where the two partietal and two frontal bones meet.

Front 23

What do sutures and fontanelles allow the bones of the skull to do?

Back 23

overlap (molding) during birth

Front 24

T/F several sutures and fontanelles remian membranous for a considerable time after birth.

Back 24

True

Front 25

T/F the bones of the vault continue to grow after birth, mainly because the brain grows.

Back 25

true

Front 26

t/f the cartilaginous neurocranium or chondrocranium of the skull initially consists of a number of separate cartilages

Back 26

true

Front 27

Those cartilages that lie in front of the rostral limit of the notochord, which ends at the level of th epituitary gland in the center of the sella turcica, are derived from ___________. (what does these things form?)

Back 27

NC Cells - the prechordal chondrocranium

Front 28

Those separate cartilages of the cartilaginous neurocranium that lie posterior to the level of the pituitary gland in the center of the sella turcica arise occipital sclerotomes fromed by ____. and form the _________ _____.

Back 28

paraxial mesoderm, chordal chondrocranium

Front 29

The base of the skull is formed when the _______- chondrocranium and _____- chondrocranium fuse and ossify by __________ossification

Back 29

prechordal, chordal, ENDOCONDRAL

Front 30

Membranous Bone Growth gives rise to _____- (flat/long) bones.

Back 30

FLAT

Front 31

de novo bone formation from undifferentiated connective tissue describes ________- (membranous/endochondra) bone growth.

Back 31

membranous

Front 32

What forms the primary ossification center of the membranous bone growth?

Back 32

Osteoprogenitor(undifferentiated mesechymal) cells of the vascularized connective tissue aggregate, forming Primary ossification center.

Front 33

How does the primary ossfication center 'grow' and expand?

Back 33

the cels differentiate to osteoblasts and lay down the collagen fibers of the osteoid and form trabeculae of woven bone

Front 34

Once osteoid is formed from the primary ossifcation center during membranous bone growth how does it take the next step to becoming bone?

Back 34

Osteoid is then mineralized into bone.

Front 35

Endochondral ossification occurs in the formation of _ and ___- bones.

Back 35

axial and radial bones

Front 36

Why is endochondral bone growth required for axial and radial bones?

Back 36

-require marked increase in length and diameter.
-since bone is rigid, it cannot grow interstitially and apposition alone is not adequate
-cartilage can grow interstitially and rapidally

Front 37

Long bones grow by _________ of cartilage with ______ and increase in bone _______ (length/width) occurs within a cartilage primordium

Back 37

replacement, bone, length

Front 38

The first step in endochondral bone growth starts with primitive __ cells that aggregate and differentiate into ________cytes.

Back 38

mesenchymal, chondrocytes.

Front 39

T/F the avascular cartilge during endochondral bone growth has crude shape of the adult bone

Back 39

T

Front 40

the avascular cartilge during endochondral bone growth has crude shape of the adult bone and is surounded by mesenchyme that differentiates into ____--

Back 40

perichondrium

Front 41

In diaphysis, bone collar forms by ___________ ossification.

Back 41

INTRAmembranous

Front 42

During endochondral bone growth - Interstitial growth by chondrocyte proliferation and accumulation of extracellular matrix is largely type ___ (I or II)

Back 42

II

Front 43

The chondrocytes in the center of the long bone during endochondral bone growth begin to __________ and apoptosis and the matrix becomes _________.

Back 43

hypertrophy, calicified

Front 44

What type of cartilage is present during the endochondral bone growth?

Back 44

hyaline

Front 45

Where does the capillary network penetrate during endochondral bone growth after the chondrocytes have hypertrophied and become calicified?

Back 45

Capillary network penetrates the hypertorphied cartilage of the diaphysis, delivering OSTEOPROGENITOR CELLS (will later become osteoBLASTS).

Front 46

Osteoblasts adhere to the _______ _______ matrix and produce _____ bone, this is the _______ bone ossification center.

Back 46

calcified cartilage matrix, primary bone, primary

Front 47

Where do secondary ossification enters appear in the growth bone during endochondral bone ossifcation?

Back 47

EPIPHYSES

Front 48

The ________ plate: is the plate of cartilage at the diaphyseal-epiphyseal junctions

Back 48

epiphyseal

Front 49

What occurs at the epiphyseal plate?

Back 49

Further lengthening of the bonea nd maturation occurs.
Closees at approximately 20 yrs. of age and lengthening ceases.

Front 50

When does the epiphyseal plate close?

Back 50

20 yrs. of age

Front 51

What are the 5 zones of the epiphyseal plate?

Back 51

Resting, Proliferative, Hypertrophic, calcified cartilage, Ossification

Front 52

From Epiphyseal end to Diaphysis name the 5 zones in order.

Back 52

Resting, Proliferative, Hypertrophic, calcified cartilage, Ossification

Front 53

Name the zone of the epiphyseal cartilage:
- hyaline cartilage on the epiphysis side

Back 53

RESTING

Front 54

Name the zone of the epiphyseal cartilage:
actively dividing chondrocytes -> stacked appearance

Back 54

Proliferative

Front 55

Name the zone of the epiphyseal cartilage:
LARGE chondrocytes, thin matrix

Back 55

Hypertrophic cartilage zone

Front 56

Name the zone of the epiphyseal cartilage:
where calcification occurs

Back 56

Calcified cartilage zone

Front 57

Name the zone of the epiphyseal cartilage:
bone tissue appears

Back 57

Ossification zone

Front 58

Mesenchyme for the frontal, nasal, lacrimal, zygomatic, maxilla, incisive, mandible, sphenoid, squamous of tmep, and hyoid bones is derived from what type of embryonic origin?

Back 58

Neural Crest cell

Front 59

What is the embryonic origin for the parietal, Petrous part of temporal bone, and Occipitals?

Back 59

paraxial mesoderm (somites and somitomeres)

Front 60

What is the embryonic origin of the laryngeals?

Back 60

Lateral plate mesoderm

Front 61

The _______cranium is the base of the skull.

Back 61

chondro

Front 62

The chondrocranium has two parts: _______ and _____.

Back 62

prechordal and chordal

Front 63

The prechordal region of the chondrocranium is derived from _____ rostral to the notochord.

Back 63

NC cells

Front 64

The Chordal chondrocranium is dervied from ___- ___ mesoderm sclerotome.

Back 64

occipital paraxial

Front 65

What type of ossification does the chondrocranium experience?

Back 65

endochondral

Front 66

What comprises the viscerocranium? (what bones of the head)

Back 66

facial bones

Front 67

What suture is found between the two frontal bones?

Back 67

metopic suture

Front 68

What suture is found between the two parietal bones?

Back 68

sagittal suture

Front 69

What suture is found between the frontal and parietal bones?

Back 69

coronal suture

Front 70

What bones come together to form the sphenoid fontanelle?

Back 70

frontal, parietal, sphenoid, temporal

Front 71

What bones of the skull come together around the occipital suture?

Back 71

parietal, occipital, temporal

Front 72

The facial bones embryonic origing is from the NC cells of the pharyngeal arches _ and _.

Back 72

1 and 2

Front 73

What two processes from the pharyngeal arches comprise most of the facial bones?

Back 73

maxillary process -> maxilla, zygomatic bone, part of the temporal bone
mandibular process-> mandible, sphenomandibular ligament, incus, malleus, stapes

Front 74

What structures does the maxillary process give rise to?

Back 74

maxilla, sygomatic bone, part of the temp. bone

Front 75

What structures does the mandibular process give rise to?

Back 75

mandible, sphenomandibular ligament, incus, malleus, stapes

Front 76

__________ is when premature closure of the one or more sutures occurs.

Back 76

craniosynostsis

Front 77

What suture has prematurely closed if you have:
scaphocephaly, - elongated ant/post.

Back 77

sagittal

Front 78

What suture has prematurely closed if you have:
acrocephaly (cone head)

Back 78

coronal suture

Front 79

What suture has prematurely closed if you have:
brachycephaly ( short head ant/post)

Back 79

coronal and lamdoid sutures

Front 80

What is the most common form of dwarfism?

Back 80

achondroplasia: malformation of cartiliage, usually genetic and associated with craniosynostosis.

Front 81

What process of the pharyngeal arches has meckel cartilage?

Back 81

mandibular process

Front 82

What are the first bones to become fully ossified?

Back 82

malleus, incus and stapes (during the 4th month)

Front 83

When do the vertebrae first begin to form?

Back 83

4th week

Front 84

What is the embryonic origin of the vertebrae?

Back 84

paraxial mesoderm (somites) -> sclerotome

Front 85

What does a typical vertebrae consist of?

Back 85

vertebral arch, foramen (through which the spinal cord passes), a body, transverse processes, and usually a spinous process.

Front 86

During the 4th week, sclerotome cells migrate around the spinal cord and notochord to merge with cells from the opposing somite on the other side of the neural tube. This will turn into:

Back 86

the vertebrae of the vertebral column

Front 87

As development of the sclerotome that is surrounding the spinal cord and notochord, continues, the sclerotome portion of the each somite also undergoes a process called, _______.

Back 87

resegmenation

Front 88

_____- occurs when the caudal half of each sclerotome grows into and fuses with the cephalic half of each subjacent sclerotome.

Back 88

resegmenation.

Front 89

T/F each vertebra is formed from the combination of the caudal half of one somite and the cranial half of its neighbor.

Back 89

True

Front 90

What gene regulates the patterns the shapes of the different vertebrae?

Back 90

HOX genes

Front 91

Mesenchymal cells between cephalic and caudal parts of the original sclerotome segment do not proliferate but fill the space between two precartilaginous vertebral bodies. In this way, they contribute to formation of the _________ _______.

Back 91

intervertebral disc

Front 92

There are _____-- cervical sclerotomes and ___ cervical vertebrae.

Back 92

eight (8) and seven (7)

Front 93

Sclerotome C1 contributes to __________ _________ and vertebra C1.

Back 93

occipital bone

Front 94

Sclerotome ___ contributes to certebrae C7 and T1

Back 94

C8

Front 95

What nerves are found above and below the C7 vertebrae?

Back 95

above: nerve C7 (sclerotome)
below: nerve C8 (sclerotome)

Front 96

What two vertebrae surround C8 sclerotome (nerve)?

Back 96

above: C7 vertebrae,
Below: T1 vertebrae

Front 97

T/F All thoracic sclerotomes (T1, etc..) are found BELOW their identical vertebrae. ex: T1 sclerotome exits below T1 vertebrae, etc...

Back 97

T

Front 98

T/F All cervical sclerotomes (C1, etc..) exit above their corresponding vertebrae. ex: C1 sclerotome (nerve) exits above C1 vertebrae

Back 98

FALSE, C8 nerve exits above T1 vertebrae and below C7 vertebrae

Front 99

The Sclerotomal mesenchyme between the caudal and cephalic sclerotome becomes ______.

Back 99

the annulus fibrosus (the stuff between each vertebrae) the 'donut'

Front 100

What does the notochordal remnant become?

Back 100

the nucleus pulposus - the jelly-like content between the vertebrae, but surrounding horizontally by annulus fibrosus. (the jelly filling in the donut)

Front 101

What is C1 also known as? (atlas or axis?)

Back 101

ATLAS

Front 102

What is C2 also known as?

Back 102

AXIS

Front 103

What vertebral defects can occur in the spinal cord?

Back 103

Scoliosis
Spina Bifida

Front 104

What two structures comprise the intervertebral disc?

Back 104

annulus fibrosus, and nucleus pulposus

Front 105

Spinal nerves exit which vertebral foramina?

Back 105

intervertebral foramina

Front 106

What cistern does the spinal nerves of the cauda equina course through?

Back 106

the lumbar cistern - (subarachnoid space)

Front 107

What has occurred when some experiences a herniated disc?

Back 107

The nucleus pulposus has leaked out of the annulus fibrosus and into the lumbar cistern (subarachnoid space)

Front 108

Describe what has occurred in Spina Bifida - specifically the reason it is called meningomyelocele.

Back 108

The meninges isn't enclosed in the spinous process because it didn't close all the way...as well as the spinal cord ( the - myelo - ) and the fluid filled cavity, subarachnoid space, as well is outside the vertebra ( the -cele)

The bifid refers to the bifid spine of vertebra (2 processes that didn't fuse into the spinous process and are now open, releasing the spinal cord, meninges, and fluid filled cavity).

Front 109

Where are the ribs derived from?

Back 109

the sclerotome of the paraxial mesoderm.

Front 110

Where is the sternum derived from?

Back 110

separate from the ribs from the somatic mesoderm in the ventral body wall (lateral plate) it is still considered part of the axial skeleton

Front 111

The Muscular System develops from what three embryonic origins?

Back 111

Paraxial mesoderm, lateral plate (splanchnic) mesoderm, and NC cells

Front 112

How does the sternum fuse?

Back 112

Two sternal bands are formed on either side of the midline, and these later fuse to form carilaginous models of the manubrium, sternebrae, and xiphoid process

Front 113

At the end of the _____- week limb buds become visible as outpocketing from the ventrolateral body wall.

Back 113

4th

Front 114

What do most of the muscles of the limb develop from?

Back 114

paraxial mesoderm

Front 115

What is the embryonic origin of the smooth muscle of the GI tract?

Back 115

lateral plate (splanchnic) mesoderm

Front 116

What does the smooth muscle found in the iris and ciliary body of the eye come from (embryonic origin)?

Back 116

NC cells

Front 117

What is the cardiac muscle derived from?

Back 117

splanchnic mesoderm surrounding the heart tube

Front 118

Skeletal muscle is derived from _________- mesoderm, which forms somites from the occipital to the sacarl regions and somitomeres in the head.

Back 118

paraxial

Front 119

Smooth muscle differentiates from _________ mesoderm surrounding the gut and its derivative and from ectoderm (pupillary, mammary gland, and sweat gland muscles).

Back 119

splanchnic (lateral plate mesoderm)

Front 120

_____ and somitomeres for the muscullature of the axial skelton, body wall, limbs and head.

Back 120

somites

Front 121

From the occipital region caudally, someite form and differentiate into the ________tome, _____-tome, and two muscle-forming regions.

Back 121

sclerotome, dermatome

Front 122

One of the regions that the somites differentiate into appears at the __________ or lip (VLL) of the prospective dermomyotome.

Back 122

ventrolateral edge

Front 123

Cells from the _______ contribute to formation of the myotome and also provide progenitor cells for limb and body wall musculature.

Back 123

VLL ventrolateral edge.

Front 124

The other region that is formed by the somites is called the _______ edge or lip (DML) of the dermomyotome, and these cells migrate ventral to the prospective dermatome and also contribute to formation of the myotome.

Back 124

dorsomedial edge

Front 125

The cell from the dorsomedial edge eventually will form the muscles of the ____. (epimeric, epaxial musculature)

Back 125

back

Front 126

The dorsomedial edge is also known as the _____mere.

Back 126

epimere

Front 127

The ventrolateral lip is also known as the _____mere.

Back 127

hypomere.

Front 128

The erector spinae, transversospinalis and dorsal ramus all originate from what myotome?

Back 128

Epimere

Front 129

Cells of the paraxial mesoderm that are found at the dorsolateral portion of the somite migrate as precursors to ______ and _______wall musculature.

Back 129

limb and body wall musculature

Front 130

Dorsomedial cells from the somite migrate beneath the remaining dorsal epithelium of the somite to form the _______.

Back 130

myotome

Front 131

Cells forming the myotome continue to extend beneath the dorsal epithelium, also known as:

Back 131

dermatome

Front 132

After ventral extension of the myotome, dermatome cells lose their epithelial configuration adn spread out under the overlying ___ to form dermis.

Back 132

ectoderm.

Front 133

What is the VLL also known as? _mere.

Back 133

hypomere

Front 134

Skeletal muscles form from the ____mere (VLL).

Back 134

hypomere

Front 135

The muscle of the tongue, strapmuscles of the neck, 3 layers of intercostals, 3 layers of the abdominal msuculature, retus abdominis, quadratus lumborum, limb musculature, ventral ramus are all examples of muscles that have developed from what MYOTOME? and what is the embryonic origin?

Back 135

Hypomere. from the paraxial mesoderm - somites

Front 136

What ramus innervates the epimere?

Back 136

Dorsal Ramus

Front 137

What ramus innervates the hypomere?

Back 137

Ventral ramus

Front 138

During differentiation, precursor cells, the ______, fuse and form long, multinucleated muscle fibers.

Back 138

myoblasts (progenitor cells)

Front 139

T/F Each spinal nerve grows into each somite at the matching level.

Back 139

True. ex: dorsal primary ramus -> dorsaomedial lip. ventral primary ramus -> ventrolateral lip

Front 140

_________ is when myogenic precursor cells elongate and ifferentiate into myoBLASTS. the myoBLASTS fuse and form elongated, multinucleate myoTUBES. Myofilaments and myofibrils develop.

Back 140

myogenesis

Front 141

During myogenesis myogenic precursor cells elongate and differentiate into myo_____.

Back 141

blasts

Front 142

Myoblasts fuse and form elongated, multincleat myo_____.

Back 142

tubes

Front 143

The head musculature is developed from the ________ mesoderm

Back 143

paraxial

Front 144

What gives rise to the limb buds during the 4th week?

Back 144

Somatic lateral plate mesoderm

Front 145

Although the Core of the limb buds is comprised of lateral plate mesodermal mesenchume the covering is comprised of________.

Back 145

ectoderm

Front 146

THe dermis of the skin is from what embryonic origin?

Back 146

paraxial mesoderm -> dermatome -> dermis

Front 147

The ______- ____ ridge (AER) induces mesenchyme to proliferatea dn remain undifferentiated = progress zone.

Back 147

apical ectodermal ridge

Front 148

The proximal lim bud start to differentiat into ________ and muscle.

Back 148

cartilage

Front 149

A pigment cell can also be described as a ______ cell

Back 149

NC (neural crest)

Front 150

The arm bud is supplied by what vertebral dermatomes?

Back 150

C4-T2

Front 151

The leg bud is supplied by what vertebral dermatomes?

Back 151

L2-S2

Front 152

What week is considered the "paddle stage" during development of the embyro?

Back 152

5th - have hand and foot plates or "paddles"

Front 153

What week is considered the "ray stage"

Back 153

The 6th week, segmental apoptosis in the AER (apical ectodermal ridge) and fingers appear as rays

Front 154

Lower limb development is _____ to____ days BEHIND the upper limb.

Back 154

1-2 days

Front 155

What develops faster, the legs or the arms?

Back 155

arms

Front 156

During what week of the embyronic development does limb rotation occur?

Back 156

7th week

Front 157

In what direction do the limbs rotate during the 7th week?

Back 157

upper limbs rotate laterally: extensors on lat/post
lower limbs rotate medially: extensors on anterior

Front 158

Where are the extensors found after week 7 in the upper and lower limbs?

Back 158

upper: lat. and post.
lower: anterior

Front 159

T/F the joints during development experience apoptosis.

Back 159

true - this is what creates the joint cavity

Front 160

What is the name of the areas of cartilage condensation and chondrogenesis arrest found in the joints?

Back 160

interzones

Front 161

What to parts of the bone meet to form a joint? (diaphysis of each, diaphysis and epiphysis, or epiphysis of each)

Back 161

epiphysis of each

Front 162

Where is the joint cavity located?

Back 162

between the ends of two bones (between epiphyses)

Front 163

During the 7th week the muscle tissue divides into a dorsal mass (aka: ________) and a ventral mass (aka: ____________).

Back 163

dorsal mass: extensor
ventral mass: flexor

Front 164

What nerve innervation does the upper and lower limb receive?

Back 164

branches from ventral primary rami
Dorsal and Ventral segmental branches

Front 165

The nerve branches fuse and form large dorsal and ventral nerves: the radial nerve supplies the ________ of the upper arm while the ___ and ______ nerve supplies the flexors of the upper arm.

Back 165

radial nerve supplies the extensors
ulnar and median supplies the flexors

Front 166

What plexus mainly supplies the lower limbs?

Back 166

lumbosacral plexus

Front 167

What two big nerves are part of the lumbosacral plexus and supply the lower limbs? be specific...

Back 167

femoral: extensors of leg
sciatic: hamstrings

Front 168

Clinical Correlation: melia means that it is limb related.
_________ : rudimentary hands/feet, but no long bones
_________: complete absence of one or more extremities.
______: fused fingers or toes
___________ : extra fingers or toes

Back 168

Phocomelia: rudimentary hands/feet, but no long bones
Amelia : complete absence of one or more extremities.
Syndactyly: fused fingers or toes
Polydactyly: extra fingers or toes

Front 169

Cardiac muscles are derived from the ______ mesoderm.

Back 169

splanchnic

Front 170

T/F the myoblasts in the cardiac muscles do not fuse/

Back 170

true. they adhere to each other via intercalated discs

Front 171

What muscle is this (skeletal, cardiac, or smooth?)
special muscles cells with larger size, fewer myofibrils -> purkinje fibers

Back 171

cardiac

Front 172

What mesoderm does smooth muscle come from?

Back 172

splanchnic/visceral lateral plate mesoderm
exception: muscles of eye and celiac are from NC cells