Muscoskeletal Development Flashcards
each sclerotome segment has a less dense portion ___ and a dense portion ___
cranially
caudally
skeletal muscle is derived from ___
cardiac muscle is derived from ___
smooth muscle is derived from ___
paraxial mesoderm
intraembryonic splanchnic mesoderm
intraembryonic splanchnic mesoderm
mesenchyme will differentiate as ___ in digits due to AER induction to fully separate the digits
hyaline cartilage
what bones are formed by endochondral ossification?
most bones (limbs & base of skull)
what forms digits in AER?
apoptosis
by end of 6t week, mesenchyme is condensing to form these outlines of future digits with webbed appearance
digital rays
thoracic & sacral are ______.
cervical & lumbar are ____.
primary curvatures (develop during fetal period)
secondary curvatures (develop after birth- told hold head up, and to walk)
separates the paraxial mesoderm from lateral plate somatic mesoderm
lateral somitic fronteir
premature closure of suture (s)
craniosynostosis
at week 12, what is present in all long bones?
ossification centers
Identify 1-3.
- anterior fontanelle
- posterior fontanelle
- sphenoid fontanelle
somites differentiate into __, ___, & ___
sclerotome
myotome
dermatome
what bones are formed by intramembranous ossification?
facial bones & some flat bones of skull
Identify 1-2.
- ectodermal lining
- mesenchyme
when does sphincter muscle of iris constrict?
when does dilater open?
bright light, when you dislike person
in response to sympathetic NS
all development is usually in what direction?
cranial to caudal
difference between endochondral & intramembranous ossification?
no cartilage model 1st in intramembranous ossification
Each myotome divides into ___ & ____
epaxial group (dorsal)
hypaxial group (ventral)
in what direction does the limb grow?
proximally to distally
Identify.
sclerotome
in 6th week, condensed mesenchyme appears at ___
joint interzones
forms all of axial skeleton except for sternum and a portion of the skull
paraxial mesoderm (sclerotome)
what forms the connective tissue of the limb (cartilage, bone, dermis, blood vessels)
mesenchyme
Identify 1-4.
- neural tube
- scleratome
- dermatome
- myotome
which limbs appear 1st?
upper limbs
absence of entire limb
amelia
Identify.
annulus fibrosis of intervertebral disc
smooth muscle is derived from ___
ectoderm
the inferior 2/3 of ___ & the superior 1/3 of ___ form the C5 vertebrae.
C5
C6
the upper limb rotates 90 degrees ___
the lower limb rotates 90 degrees ____
laterally
medially
some of dense portion of sclerotome forms annulus fibrosis, remaingin dense portion fuses with less dense portion to form vertebral body
resegmentation
Identify.
lateral somitic fronteir
some ventrolateral myoblasts will migrate across fronteir into lateral plate somatic mesoderm to form ____
skeletal muscle of limb
which muscles of eye are derived from neuroectoderm?
sphincter pupillae & dilator pupillae of the iris
when do limb buds emerge?
end of wk 4
3 types of joints?`
fibrous
cartilaginous
synovial
grow out as lateral extensions of costal processes developing from thoracic vertebrae, & wrap around anteriorly
ribs
Identify.
sternal bands
extra digits
polydactyly
in what direction do somites form?
cranially to caudally
each spinal nerve divides into a ___ & ____
dorsal primary ramus
ventral primary ramus
Identify.
paraxial mesoderm
Identify 1-4.
1- Cervical
2- Thoracic
3- Lumbar
4- Sacral
bones of face, portion of neurocranium, and hyoid bone are formed from ___
neural crest cells
What are these bones derived from?
What type of ossification occurs?
neural crest cells
intramembranous ossification
innervated by ventral primary rami
hypaxial muscles
The viscerocranium is mostly formed from neural crest of which arches?
1st 2 pharyngeal arches
joint interzone gives rise to…
ligaments, synovial membrane, menisci
At which vertebral level is there a spinal nerve, but no vertebral body?
C8
when does limb rotation occur?
week 7
at birth, what is status of limb ossification?
diaphysis completely ossified, epiphysis still cartilagenous
absence of part of a limb
meromelia
Identify.
digital ray
premature closure of sagittal suture
scaphocephaly
enlarged membranous spaces where 2+ bones meet
fontanelles
when does endochondral ossification of limb bones occur?
at end of 8th week
what areas of long bone ossify after birth?
epiphysis
pectoral & pelvic girdles, limb bones, sternum all formed from _____
lateral plate mesoderm
Identify 1-3.
- dorsomedial muscle cells
- dermatome
- ventrolateral muscle cells
bone-forming tissue comes from ___ & ___
paraxial mesoderm & neural crest
fewer digits
syndactyly
myoepithelial cells of mammary, salivary, & sweat glands are derived from ___
surface ectoderm
vertebral columb ribs, portion of neurocranium is formed from _____
paraxial mesoderm
Identify 1-3.
- Costal process
- Rib
- Costovertebral joint (a synovial joint)
paraxial mesoderm condenses to form cube-like segments called ___
somites
innervated by dorsal primary rami
epaxial muscles
fibrous joints uniting the flat bones of the skull
sutures
dermatome forms ___
myotome forms ____
sclerotome forms ___
dermis of back
skeletal muscle
vertebrae, ribs, portion of neurocranium
Blue areas are derived from ____.
Orange areas are derived from ___.
neural crest
paraxial mesoderm
Identify 1-2.
- Progress zone
- AER
induced to form by ribs at ventral midline from lateral plate somatic mesoderm
sternum
what forms where costal process meets vertebra?
synovial joint
sends signaling factors to nearby mesenchyme during elongation of limbs
AER- apical ectodermal ridge
where are sclerotome cells found?
surrounding neural tube & notochord
what do somites give rise to?
most of axial skeleton & associated musculature & overlying dermis of back
the differences in location of extensor & flexor muscle compartments when comparing the upper limb and the lower limb can be explained by this event
limb rotation
Identify.
joint interzone
when do 2 sternal bars fuse cranially to caudally?
10th week
above C7, spinal nerves…
below C7, spinal nerves…
come out ABOVE vertebral body
comt out BELOW vertebral body
area that keeps cells undifferentiated and rapidly dividing to form more limb tissue
progress zone
made up of vertebrae, intervertebral discs, ribs, sternum, and skull
axial skeleton
What are these bones derived from?
What type of ossification occurs?
both paraxial mesoderm & neural crest
intramembranous & endochondral ossification
made up of pectoral & pelvic girdles and limb bones
apendicular skeleton
what forms the tissue that unites the bones of a joint?
mesenchyme
this area of skull forms via endochondral ossification. It is base of skull.
chondrocranium
premature closure of coronal suture
brachycephaly
skeletal muscle forms from ___
paraxial mesoderm
by end of what week is a complete set of cartilage model formed?
8th wk
limb bud has a core of ___ lined by ___
mesenchyme
surface ectoderm
when are digits fully separated?
by end of 8th week
Identify.
somites
