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ANAT 400 - Embryology > Skeletal System > Flashcards

Skeletal System Flashcards

1
Q

What are the two divisions of the skeletal system

A
  • Axial skeleton (80 bones)
    • Skull, vertebral column, ribs, sternum
  • Appendicular skeleton (126 bones)
    • bones of limbs and limb girdles
    • forms core of limbs
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2
Q

Formation of the axial skeleton is directed by ______

A

Formation of the axial skeleton is directed by the soft tissues it protects (brain, spinal cord, lungs, heart etc)

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3
Q

Morphogenesis of limb bones (appendicular skeleton) is inherent to _____

A

Morphogenesis of limb bones (appendicular skeleton) is inherent to limb mesoderm

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4
Q

What are the two ways to make a bone?

A
  • Endochondral ossification
    • formed from a cartilage template
    • all bones of trunk and limbs except clavicle
    • bones derived from pharyngeal arch cartilages
    • cranial base, sensory capsules
  • Intramembranous ossification
    • Ossification of mesenchyme without a cartilage intermediate
    • Especially flat bones
    • Most bones of face and skull
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5
Q
  • Endochondral ossification:
    • formed from _______
    • all bones of _____ and _____ except clavicle
    • bones derived from _____ _____ cartilages
    • cranial base, sensory capsules
A
  • Endochondral ossification
    • formed from a cartilage template
    • all bones of trunk and limbs except clavicle
    • bones derived from pharyngeal arch cartilages
    • cranial base, sensory capsules
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6
Q
  • Intramembranous ossification
    • Ossification of ______ without a cartilage intermediate
    • Especially _____ bones
    • Most bones of ____ and ____
A
  • Intramembranous ossification
    • Ossification of mesenchyme without a cartilage intermediate
    • Especially flat bones
    • Most bones of face and skull
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7
Q

The neurocranium:

Viscerocranium is:

A

The neurocranium: part of the skull housing the brain

Viscerocranium is: bones of the face

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8
Q

Both neurocranium and viscerocranium are formed mainly by ______ but are derived from different tissues

  • Neurocranium → mostly from _______ and some ____
  • Viscerocranium → mostly ______
A

Both neurocranium and viscerocranium are formed mainly by dermal bone but are derived from different tissues

  • Neurocranium → mostly from paraxial mesoderm (unsegmented and from somites) and some neural crest
  • Viscerocranium → mostly neural crest
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9
Q

At birth, flat bones of the calvaria (cranial vault - top portion of neurocranium) are separated by _______ and _____

Allow for ______ of the skull during birth and ______

A

At birth, flat bones of the calvaria (cranial vault - top portion of neurocranium) are separated by fibrous sutures and soft spots (fontanelles) where the sutures intersect

Allow for flexibility of the skull during birth and postnatal growth of the brain

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10
Q
  • Sutures and fontanelles will eventually ossify through _______
  • fontanelles will close in ______
  • Timing of ossification of the sutures is variable but extends into ______
A
  • Sutures and fontanelles will eventually ossify through intramembranous ossification
  • fontanelles will close in first few months to years
  • Timing of ossification of the sutures is variable but extends into adulthood
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11
Q

Skull grows in _____ and ____

A

Skull grows in thickness and volume

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12
Q

What is craniosynostosis?

A
  • Premature closure of 1 or more sutures which limits growth of the brain
    • lead to deformation of the skull as growth at other sutures is disproportionate
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13
Q

Formation of the chondrocranium:

  • Cartilage forms around ______, thereby leaving holes in skull base
  • Most of the cartilage of the chondrocranium ______ but there are joints between at which growth can still occur postnatally
A

Formation of the chondrocranium:

  • Cartilage forms around cranial nerves, thereby leaving holes in skull base
  • Most of the cartilage of the chondrocranium ossifies by birth but there are joints between at which growth can still occur postnatally
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14
Q

Where are each of the numbered regions of the chondrocranium derived?

1, 2, 3

A
  1. Neural crest
  2. Cranial paraxial mesoderm
  3. Occipital somites
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15
Q

The skull base joints are _______: joints where cartilage joins 2 bones together

_______ joint is a major site of skull base growth; only starts to ossify at puberty

A

The skull base joints are synchondroses: joints where cartilage joins 2 bones together

spheno-occipital synchondrosis (joint) is a major site of skull base growth; only starts to ossify at puberty

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16
Q

Small pieces of the viscerocranium are derived from cartilage - these come from ________

Almost all of the viscerocranium is ______-derived ____ bone

A

Small pieces of the viscerocranium are derived from cartilage - these come from pharyngeal arch cartilages

Almost all of the viscerocranium is neural crest-derived dermal bone

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17
Q
  • _________ develop as diverticula off the walls of the nasal cavity
A

paranasal sinuses develop as diverticula off the walls of the nasal cavity

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18
Q

What are paranasal sinuses and why are they functionally important in development?

A
  • Paranasal sinuses
    • develop as diverticula off the walls of the nasal cavity
      • Become air-filled extensions into the adjacent bone
      • Maxillary sinuses develop late fetal life (form first)
      • Remaining paranasal sinuses develop postnatally
  • Sinuses drive change in skull as child grows
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19
Q

Growth of the ______ is dramatic over the early postnatal years

A

Growth of the viscerocranium is dramatic over the early postnatal years

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20
Q

Vertebral column:

  • ______ set up pattern for vertebrae
A

Vertebral column:

  • somites set up pattern for vertebrae
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21
Q

Formation of the vertebral column begins with somites

  • Somites develop in pairs on either side of the _____ in ______ succession
  • Soon after formation, the ventral-medial portion of the somite becomes the ______
A

Formation of the vertebral column begins with somites

  • Somites develop in pairs on either side of the neural tube in cranial-caudal succession
  • Soon after formation, the ventral-medial portion of the somite becomes the sclerotome
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22
Q

______ resegments to form the vertebrae and ribs

A

sclerotome resegments to form the vertebrae and ribs

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23
Q
  • Caudal portion of sclerotome is inhibitory for ______
  • Axons travel through the ______
  • Division between cranial and caudal portions is marked by _______
  • ___________ follows the same path to form sensory neurons
A
  • Caudal portion of sclerotome is inhibitory for motoneuron axon growth
  • Axons travel through the cranial portions of sclerotomes
  • Division between cranial and caudal portions is marked by von Ebner’s fissure
  • Neural crest cell migration follows the same path to form sensory neurons
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24
Q
  • Sclerotomes reorganize
    • Caudal portion of each sclerotome merges with ______
    • _______ (initially dermomyotome) do not resegment and become attached to ______
A
  • Sclerotomes reorganize
    • Caudal portion of each sclerotome merges with cranial portion of the next sclerotome
    • myotomes (initially dermomyotome) do not resegment and become attached to 2 adjacent vertebrae
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25
Q

Spinal nerves travel through ______ to reach muscles

A

Spinal nerves travel through intervertebral foramina

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26
Q

Somites and sclerotome on both sides = one vertebra is made of ________ to reach muscles (ie it takes ______ to make 1 vertebrae)

A

Somites and sclerotome on both sides = one vertebra is made of 4 dif sclerotome pieces to reach muscles (ie it takes portions of 4 sclerotomes to make 1 vertebrae)

eg: C4 vertebra is created by caudal halves of left and right C4 sclerotome + cranial halves of left and right C5 sclerotome

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27
Q

What fuses to form the base of the occipital bone?

A
  • The occipital sclerotomes (1-4) plus the cranial part of sclerotome C1 fuse to form base of the occipital bone
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28
Q

________ fuses with _____ to form the C1

_______ fuses with _____ to make the C2 vertebra etc

A

Caudal C1 sclerotome fuses with cranial C2 to form the C1

Caudal C2 fuses with cranial C3 to make the C2 vertebra etc

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29
Q

Why is there a C8 sclerotome but NOT a C8 vertebra?

ie 7 cervical vertebra and 8 cervical somites

A
  • The caudal C8 sclerotome fuses with Cranial T1 sclerotome to make the T1 vertebra
    • Cranial half contribute to C7
  • Therefore only 7 Cervical vertebra are made from 8 cervical somites
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30
Q

While there isn’t a C8 vertebra, there are 8 pairs of cervical spinal nerves

How are the Nerves organized via where they exit through the vertebra?

A
  • C1-C7: associated nerve root exits above the vertebra
  • C8: exits between C7 & T1
  • T1-S4: associated nerve root exits below the vertebra
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31
Q

Intervertebral discs:

  • _______ within vertebra disappears; but that within disc expands to become the gelatinous nucleus pulposus
A

Intervertebral discs:

  • notochord within vertebra disappears; but that within disc expands to become the gelatinous nucleus pulposus
32
Q

What happens to sclerotome cells remaining between vertebrae following resegmentation?

A
  • Sclerotome cells remaining will become arranged in circular fibers of the annulus fibrosus
  • the inner portion of the annulus fibrosus will become fibrocartilage
33
Q
  • Sclerotome cells remaining between vertebrae following resegmentation will become arranged in circular fibers of the _________
  • the inner portion of which will become ________
A
  • Sclerotome cells remaining will become arranged in circular fibers of the annulus fibrosus
  • the inner portion of the annulus fibrosus will become fibrocartilage
34
Q

Inner portion of the annulus fibrosus becomes ______

A

Inner portion of the annulus fibrosus becomes fibrocartilage

35
Q

Vertebral formation - cartilage

  • The cartilage model develops as _____ each with own _______
  • If cartilaginous vertebral arches fail to fuse, results in ________
A

Vertebral formation - cartilage

  • The cartilage model develops as 5 pieces each with own ossification centres
  • If cartilaginous vertebral arches fail to fuse, results in spina bifida occulta (bone around neural tube is open - no cartilage = no bone)
36
Q

Vertebral formation - bone

  • The vertebrae are mainly ______ at birth but certain areas remain cartilaginous and act as ______
A

The vertebrae are mainly ossified at birth but certain areas remain cartilaginous and act as growth plates

  • These areas are:
    • Costovertebral joint
      • never fusing
    • Annular epiphysis
      • allows growth in height
    • Spinous process
37
Q

The vertebrae are mainly ossified at birth but certain areas remain cartilaginous and act as growth plates

  • These areas are:
    • _________
      • never fusing
    • _________
      • allows growth in height
    • _________
A

The vertebrae are mainly ossified at birth but certain areas remain cartilaginous and act as growth plates

  • These areas are:
    • Costovertebral joint
      • never fusing
    • Annular epiphysis
      • allows growth in height
    • Spinous process
38
Q
  • The neural arches fuse in years____
  • The arches fuse with the vertebral body in year ____
  • Secondary ossification centers for the _______, _________, heads of ____ and ________ appear at puberty but ossification isn’t fully complete until about ____ years
A
  • The neural arches fuse in years 3-5
  • The arches fuse with the vertebral body in year 6
  • Secondary ossification centers for the spinous process, transverse processes, heads of ribs and annular epiphyses appear at puberty but ossification isn’t fully complete until about 25 years
39
Q

Label the thoracic vertebra

A
40
Q

Label the Cervical vertebra

Lumbar vertebra

and Sacral vertebra

A
41
Q

Part of the ______ for C1 became incorporated into C2 to create the ______

A

Part of the centrum for C1 became incorporated into C2 to create the dens

42
Q

Each segment of the vertebral column has a distinct morphology, what establishes this cranial-caudal pattern and where is it established?

A

The cranial-caudal pattern is established early within the sclerotome by the expression of Hox genes

43
Q

Hox genes pattern the cranial-caudal axis

  • Hox genes are ______ arranged in _____ within the genome
  • They’re expressed in specific but overlapping regions along the ________ axis of the embryo
A

Hox genes pattern the cranial-caudal axis

  • Hox genes are transcription factors arranged in 4 paralogous clusters within the genome
  • They’re expressed in specific but overlapping regions along the cranial-caudal axis of the embryo
44
Q

Each vertebra (or two) expresses a unique set of _____ and has a unique morphology

_______ causes limbs to arise at specific places:

  • upper limbs at _______
  • lower limbs at _______
A

Each vertebra (or two) expresses a unique set of hox genes and has a unique morphology

Hox patterning causes limbs to arise at specific places:

  • upper limbs at cervical/thoracic boundary
  • lower limbs at lumbar/sacral boundary
45
Q

Vertebral and rib anomalies:

Scoliosis:

A

Scoliosis:

Lateral curvature of spine:

Can result from failure of one half of vertebra to form

46
Q

What is an accessory rib?

A

Extra rib developing from cervical or lumbar vertebrae

47
Q

Vertebral and rib anomalies can arise from (3)

A
  • Changes to cranial-caudal patterning (Hox genes)
  • Changes to genes important for segmentation
  • Genes important for vertebral formation
48
Q

Label the types of congenital scoliosis

A
49
Q

Label the sternum

Green-

Blue -

Purple -

A
50
Q

The first 7 pairs of ribs (true ribs) connect to the ______ via _______

The 5 lower pairs of ribs do not connect directly to the _____ and are called false ribs

A

The first 7 pairs of ribs (true ribs) connect to the sternum via costal cartilages

The 5 lower pairs of ribs do not connect directly to the sternum and are called false ribs

51
Q
  • Clavicle is derived from _____ and undergoes _______ ossification
A

Clavicle is derived from neural crest and undergoes intramembranous ossification

52
Q

The sternum develops initially as _______ called sternal bars which are derived from _______

A

The sternum develops initially as mesenchymal condensations called sternal bars which are derived from lateral plate mesoderm

53
Q

Sternal bars converge at the ______ from cranial to caudal

A

Sternal bars converge at the midline from cranial to caudal

54
Q

During fusion, the sternal bars _______

The sternum then segments and develops numerous ________ (form beside where the ribs connect to the sternum)

A

During fusion, the sternal bars chondrify

The sternum then segments and develops numerous ossification centres (form beside where the ribs connect to the sternum) – signaling cues

55
Q

Where are the ossification centres of the sternum? (6)

A
  • 1 in manubrium
  • 4 in body
  • 1 in xiphoid process

NOT ALL PRESENT AT THE SAME TIME (eg xiphoid OC doesn’t appear until adulthood)

56
Q

When do the sternal segment fuse?

A
  • By 25 years, the sternal segments have mainly fused, leaving final organization of manubrium, body and xiphoid process
  • Xiphoid process will eventually ossify and fuse with the body in midlife
57
Q

Cellular origins of cartilage and bone:

  • _______: make cartilage
  • ______ make bone
  • _______ resorb bone
A

Cellular origins of cartilage and bone:

  • chondrocytes: make cartilage
  • osteoblasts make bone
  • osteoclasts resorb bone
58
Q

Both chondrocytes and osteoblasts originate from _________

  • ________ (axial skeleton and occipital bone)
  • _______ (appendicular skeleton and sternum)
  • ______ (cartilage of face and neck)
A

Both chondrocytes and osteoblasts originate from mesenchymal stem cells

  • paraxial mesoderm (axial skeleton and occipital bone)
  • lateral plate mesoderm (appendicular skeleton and sternum)
  • neural crest cells (cartilage of face and neck)
59
Q

Dermal bones originate from _______ or _______

A

Dermal bones originate from neural crest cells or paraxial mesoderm

60
Q

Intramembranous ossification

  • Small clusters are mesenchymal cells differentiate as ______
A

Intramembranous ossification

  • Small clusters are mesenchymal cells differentiate as osteoblasts
61
Q

Intramembranous ossification

  • Small clusters are mesenchymal (NC or parax mesod) cells differentiate as osteoblasts
  • Osteoblasts secrete ________ (organic component of bone, which calcify over a few days forming a _____)
A

Intramembranous ossification

  • Small clusters are mesenchymal (NC or parax meso) cells differentiate as osteoblasts
  • Osteoblasts secrete osteoid (organic component of bone, which calcify over a few days forming a bone spicule)
62
Q

Intramembranous ossification

  • Small clusters are mesenchymal (NC or parax meso) cells differentiate as osteoblasts
  • Osteoblasts secrete osteoid (organic component of bone, which calcify over a few days forming a bone spicule)
  • Osteoblasts trapped in the bone become ________
A

Intramembranous ossification

  • Small clusters are mesenchymal (NC or parax meso) cells differentiate as osteoblasts
  • Osteoblasts secrete osteoid (organic component of bone, which calcify over a few days forming a bone spicule)
  • Osteoblasts trapped in the bone become osteocytes (spinous processes but not dividing)
63
Q

Intramembranous ossification

  • Small clusters are mesenchymal (NC or parax meso) cells differentiate as osteoblasts
  • Osteoblasts secrete osteoid (organic component of bone, which calcify over a few days forming a bone spicule)
  • Osteoblasts trapped in the bone become osteocytes (spinous processes but not dividing)
  • Spicules of bone grow through secretion of _____ by surrounding osteoblasts
A

Intramembranous ossification

  • Small clusters are mesenchymal (NC or parax meso) cells differentiate as osteoblasts
  • Osteoblasts secrete osteoid (organic component of bone, which calcify over a few days forming a bone spicule)
  • Osteoblasts trapped in the bone become osteocytes (spinous processes but not dividing)
  • Spicules of bone grow through secretion of osteoid by surrounding osteoblasts
64
Q

Intramembranous ossification

  • Small clusters are mesenchymal (NC or parax meso) cells differentiate as osteoblasts
  • Osteoblasts secrete osteoid (organic component of bone, which calcify over a few days forming a bone spicule)
  • Osteoblasts trapped in the bone become osteocytes (spinous processes but not dividing)
  • Spicules of bone grow through secretion of osteoid by surrounding osteoblasts
  • Spicules join together to form ______ which grow around blood vessels. this is called _______
A

Intramembranous ossification

  • Small clusters are mesenchymal (NC or parax meso) cells differentiate as osteoblasts
  • Osteoblasts secrete osteoid (organic component of bone, which calcify over a few days forming a bone spicule)
  • Osteoblasts trapped in the bone become osteocytes (spinous processes but not dividing)
  • Spicules of bone grow through secretion of osteoid by surrounding osteoblasts
  • Spicules join together to form Trabeculae (beams) which grow around blood vessels. this is called woven bone
65
Q

Intramembranous ossification

  • Small clusters are mesenchymal (NC or parax meso) cells differentiate as osteoblasts
  • Osteoblasts secrete osteoid (organic component of bone, which calcify over a few days forming a bone spicule)
  • Osteoblasts trapped in the bone become osteocytes (spinous processes but not dividing)
  • Spicules of bone grow through secretion of osteoid by surrounding osteoblasts
  • Spicules join together to form Trabeculae (beams) which grow around blood vessels. this is called woven bone
  • Surrounding mesenchyme condenses to form a sheath called the _______ which includes a population of osteoblasts
A

Intramembranous ossification

  • Small clusters are mesenchymal (NC or parax meso) cells differentiate as osteoblasts
  • Osteoblasts secrete osteoid (organic component of bone, which calcify over a few days forming a bone spicule)
  • Osteoblasts trapped in the bone become osteocytes (spinous processes but not dividing)
  • Spicules of bone grow through secretion of osteoid by surrounding osteoblasts
  • Spicules join together to form Trabeculae (beams) which grow around blood vessels. this is called woven bone
  • Surrounding mesenchyme condenses to form a sheath called the periosteum which includes a population of osteoblasts
66
Q

Intramembranous ossification

  • Small clusters are mesenchymal (NC or parax meso) cells differentiate as osteoblasts
  • Osteoblasts secrete osteoid (organic component of bone, which calcify over a few days forming a bone spicule)
  • Osteoblasts trapped in the bone become osteocytes (spinous processes but not dividing)
  • Spicules of bone grow through secretion of osteoid by surrounding osteoblasts
  • Spicules join together to form Trabeculae (beams) which grow around blood vessels. this is called woven bone
  • Surrounding mesenchyme condenses to form a sheath called the periosteum which includes a population of osteoblasts
  • The trabeculae under the periosteum are replaced by _______ creating 2 plates sandwiching th e______
A

Intramembranous ossification

  • Small clusters are mesenchymal (NC or parax meso) cells differentiate as osteoblasts
  • Osteoblasts secrete osteoid (organic component of bone, which calcify over a few days forming a bone spicule)
  • Osteoblasts trapped in the bone become osteocytes (spinous processes but not dividing)
  • Spicules of bone grow through secretion of osteoid by surrounding osteoblasts
  • Spicules join together to form Trabeculae (beams) which grow around blood vessels. this is called woven bone
  • Surrounding mesenchyme condenses to form a sheath called the periosteum which includes a population of osteoblasts
  • The trabeculae under the periosteum are replaced by lamellar bone creating 2 plates sandwiching the woven bone
67
Q

Endochondral ossification:

  • The trancription factor _______ turns on mesenchymal condensations and induces the differentiation of chondrocytes
A

Endochondral ossification:

  • The trancription factor Sox 9 turns on mesenchymal condensations and induces the differentiation of chondrocytes
68
Q

Endochondral ossification:

  • The trancription factor Sox 9 turns on mesenchymal condensations and induces the differentiation of chondrocytes
  • Chondrocytes secrete _______ creating a small cartilage model of the bone
A

Endochondral ossification:

  • The trancription factor Sox 9 turns on mesenchymal condensations and induces the differentiation of chondrocytes
  • Chondrocytes secrete extracellular matrix proteins (eg collagen type II) creating a small cartilage model of the bone
69
Q

Endochondral ossification:

  • The trancription factor Sox 9 turns on mesenchymal condensations and induces the differentiation of chondrocytes
  • Chondrocytes secrete extracellular matrix proteins (eg collagen type II) creating a small cartilage model of the bone
  • Chondrocytes pass through 4 different stages:
    • ______
    • ______
    • _____
    • ________
  • Cells in the middle are the first to ______ and these cells secrete an attractant for blood vessels
A

Endochondral ossification:

  • The trancription factor Sox 9 turns on mesenchymal condensations and induces the differentiation of chondrocytes
  • Chondrocytes secrete extracellular matrix proteins (eg collagen type II) creating a small cartilage model of the bone
  • Chondrocytes pass through 4 different stages:
    • resting
    • proliferating
    • prehypertrophic
    • hypertrophic
  • Cells in the middle are the first to hypertrophy and these cells secrete an attractant for blood vessels
70
Q

Endochondral ossification:

  • The trancription factor Sox 9 turns on mesenchymal condensations and induces the differentiation of chondrocytes
  • Chondrocytes secrete extracellular matrix proteins (eg collagen type II) creating a small cartilage model of the bone
  • Chondrocytes pass through 4 different stages:
    • resting
    • proliferating
    • prehypertrophic
    • hypertrophic
  • Cells in the middle are the first to hypertrophy and these cells secrete an attractant for blood vessels
  • Hypertrophic chondrocytes can either _____ or _______
A

Endochondral ossification:

  • The trancription factor Sox 9 turns on mesenchymal condensations and induces the differentiation of chondrocytes
  • Chondrocytes secrete extracellular matrix proteins (eg collagen type II) creating a small cartilage model of the bone
  • Chondrocytes pass through 4 different stages:
    • resting
    • proliferating
    • prehypertrophic
    • hypertrophic
  • Cells in the middle are the first to hypertrophy and these cells secrete an attractant for blood vessels
  • Hypertrophic chondrocytes can either undergo apoptosis or change into osteoblasts
71
Q

Endochondral ossification:

  • The trancription factor Sox 9 turns on mesenchymal condensations and induces the differentiation of chondrocytes
  • Chondrocytes secrete extracellular matrix proteins (eg collagen type II) creating a small cartilage model of the bone
  • Chondrocytes pass through 4 different stages:
    • resting
    • proliferating
    • prehypertrophic
    • hypertrophic
  • Cells in the middle are the first to hypertrophy and these cells secrete an attractant for blood vessels
  • Hypertrophic chondrocytes can either undergo apoptosis or change into osteoblasts
  • The invading blood vessels bring _____ and _____ which will make and remodel bone in the primary ossification centre
  • At the same time: Osteoblasts differentiate in the ________ and create a bony collar
A

Endochondral ossification:

  • The trancription factor Sox 9 turns on mesenchymal condensations and induces the differentiation of chondrocytes
  • Chondrocytes secrete extracellular matrix proteins (eg collagen type II) creating a small cartilage model of the bone
  • Chondrocytes pass through 4 different stages:
    • resting
    • proliferating
    • prehypertrophic
    • hypertrophic
  • Cells in the middle are the first to hypertrophy and these cells secrete an attractant for blood vessels
  • Hypertrophic chondrocytes can either undergo apoptosis or change into osteoblasts
  • The invading blood vessels bring osteoblasts and osteoclasts which will make and remodel bone in the primary ossification centre
  • At the same time: Osteoblasts differentiate in the perichondrium (no called Periosteum) and create a bony collar
72
Q

Where is the primary ossification centre of endochondral ossification?

What is arranged on either side?

A
  • In the middle of the diaphysis (shaft) of a long bone
  • Hypertrophic, prehypertrophic, proliferating and resting chondrocytes are arranged in layers on either side
73
Q

Where is the primary ossification centre of endochondral ossification?

What is arranged on either side?

A
  • In the middle of the diaphysis (shaft) of a long bone
  • Hypertrophic, prehypertrophic, proliferating and resting chondrocytes are arranged in layers on either side
74
Q

At birth, the ______ is mostly ossified but the ______ are still cartilage

After birth, _______ appear in the epiphyses

A

At birth, the diaphysis is mostly ossified but the epiphyses (ends) are still cartilage

After birth, secondary ossification centres appear in the epiphyses (growth plates)

75
Q

Growth plates:

  • Once a secondary ossification centre forms, it expands ______ to ossify most of the _______
A

Growth plates:

  • Once a secondary ossification centre forms, it expands radially to ossify most of the epiphysis
76
Q

Growth plates:

  • the epiphyseal cartilage plate remains between _____ and ______
    • this is where most of the _______ occurs through ______ and ______
A

Growth plates:

  • the epiphyseal cartilage plate remains between diaphysis and epiphysis
    • this is where most of the lengthening growth occurs through proliferation of chondrocytes and replacement by bone
77
Q

Bone is remodeled throughout life but will not grow in length once the _______ close.

Bones can grow appositionally in response to exercise

A

Bone is remodeled throughout life but will not grow in length once the growth plates close.

Bones can grow appositionally in response to exercise

ANAT 400 - Embryology (14 decks)

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