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46 Cards in this Set

  • Front
  • Back
The skeletal and muscular systems develop mostly from the embryonic ?

What cells form the facial skeleton?

neural crest cell => facial skeleton
What mesoderm forms the VISCERAL (musculature of the gut) and SOMATIC (contributes with the dermatome, to form the dermis) portions?
Lateral mesoderm
Intermediate Mesoderm gives rise to the future site for development of the ? system

area is called aka NEPHROTOME
Paraxial mesoderm forms ? and ? which will form the most of the skeletal and muscular systems.

Around DAY ? the paraxial mesoderm begins to segment in a cranio caudal orientation beginning at the neck or cervical region.
Day 20
SOMITES organize into what three regions of mesoderm?


? is unregulated in the ventral portion of the SOMITE is a maker of the presumptive SCLEROTOME
in response to ? , PAX1 positive ventral SOMITE cells separate to become a loosely associated mass migrating toward the notochord.
What part of the somties will become the BONE and CARTILAGE components?
The skull is divided into the ? which surrounds the brain and the ? which makes up the facial skeleton
Neurocranium = surrounds brain

Viscerocranium = facial skeleton
NEUROCRANIUM is derived from ? and ?
Occipital Somites

Neurocranium is subdivided into the ? (cranial vault), and the ? (base of the skull)
membranous neurocranium (cranial vault)

cartilaginous neurocranium (base of the skull)
How are the flat bones of the skull formed from mesoderm?
Membranous Ossification
flat bones of the skull are separated by CT seams called ?
? plays a critical role in suture FORMATION and abnormalities in the RECEPTOR is associated with FUSION of the sutures or craniosynostosis.
FGF = suture formation

FGF Receptor = fusion of sutures
A site where several bones meet a wide connective tissue bridge is called ?
At what age does the Posterior Fontanelle (2 parietal + occipital bone) close?
3 months of age
at what age does the Anterior Fontanelle (2 parietal + 2 frontal bones) close?
18 months of age
? is derived from mesoderm surrounding the Notochord and Occipital Sclerotomes.
Cartilaginous neurocranium
DORSAL portion of the FIRST ARCH gives rise to the ?
Maxillary Process
-Maxilla Bone
-Zygomatic Bone
-Temporal Bone
VENTRAL portion of the FIRST ARCH is the ?
Mandibular Process

gives rise to the MANDIBLE!!

--dorsal portion of the first arch is the maxillary process
abnormalities in the Dorsal Tip of the FIRST ARCH (mandibular process) will affect what bones?

abnormalities in the Dorsal Aspect of the SECOND ARCH will affect what bone?
What bone is the First to begin ossification?

What bone is the First to COMPLETE ossification?
CLAVICLE = first to begin ossification

BONES OF MIDDLE EAR = first to COMPLETE ossification!!!
True or False

Paranasal sinuses have already developed.

paranasal sinuses have NOT yet developed
the most VENTRAL cells of each SOMITE below the occipital region migrate toward the Notochord and condense into segmentally arranged ?
Primary Sclerotomes
PRIMARY SCLEROTOMES differentiation into what 2 portions?

Less Cellular Cranial portion
Dense Cellular Caudal portion

caudal portion drifts and fuses with adjacent cranial sclerotome to form secondary/definitive sclerotome
What gives rise to the Nucleus Pulposus?

What gives rise to the Annulus Fibrosus?

loose ring of Mesodermal Cells
The ribs are extensions of the developing thoracic vertebra and thus develop from the ?
? is a disruption of normal endochondral ossification and leads to DWARFISM
Hyperpituitarism (increased GH) can cause ? (enlargement of the face, hands, and feet) or ? (overall enlarged growth).
Acromegaly (enlargement of the face, hands and feet)

Gigantism (overall enlarged growth)
A patient with ACRANIA (cranioschisis) is associated with ? and due to lack of neural induction of the mesoderm to form a cranial vault.
Anencephaly (no brain)
smaller defects in formation of the cranium can result in herniation of the brain called ? or meninges ?

? is usually due to failure of the brain to grow rather than premature closure of all the sutures.
FGF-Receptor abnormalities are associated with syndromes of ? and other bony fusions.
? syndrome is a reduction int he number of cervical vertebrae.
Klippel-Feil Syndrome
Failure of a large number of vertebral arches to fuse is called ?
A patient with SCOLIOSIS may have what abnormality in the vertebra?

1/2 of a vertebra (laterally) fails to form.
NEURAL TUBE secretes ? proteins that stimulate cells of the MYOTOME to become ?
Wnt proteins

epaxial muscles
true or false

Myotome are MyoD transcription factor POSITIVE
? proteins from the dorsal ectoderm and ? from the lateral plate mesoderm induce the nearest Myotome cells to migrate ventrally for the body wall and limbs.
Wnt proteins

BMP lateral plate mesoderm
As the cells migrate they elongate and form a spindle shape becoming identifiable as ?

they fuse to form the definitive multinucleated MUSCLE FIBERS
Facial Connective Tissue is derived from ?

Occipital and Cervical Connective Tissue is derived from ?
Neural Crest Cells

CT and the body wall and limbs is derived from the ?
SOMATIC MESODERM of the Lateral Plate Mesoderm (LPM)
by the end of the ? week the myotome has arranged into a small dorsal portion called ? and a ventral primary ramus called ?
Epimere (dorsal primary ramus)

Hypomere (ventral primary ramus)
the EPIMERE forms the ? muscles

HYPOMERE forms the ? muscles
EXTENSOR = epimere

FLEXORS = hypomere