Musculoskeletal & limb development Flashcards
Periaxial mesoderm forms what
neurocranium & torso
paraxial mesoderm initially forms ____ which tontinue to form beginning week 4 to form ___
somitomeres
somites
What is the difference b/w somitomeres and somites
somitomeres are not as organized
what is the nature of somite and its components
segmented - are discreet
sclerotome differentiates into what
cartilage, bone, joints of axial skeleton, neurocranium
what part of body has sclerotom and somite?
spine
does spinal cord or neural tube move?
no
what moves around the spinal cord
sclerotome
as the neck grows what happens to the vertebrae
vertebrae will float up
what happens to myotome as baby grows
muscles stretch - muscles dont float up with vertebrae as spinal cord gets bigger, they stretch
what happens to arteries in back as baby grows
they will stretch with the muscles
what happens to nerves in back as baby grows
they will stretch
where do ribs originate from?
back - grow from thoracic vertebra in paraxial mesoderm
where do ribs grow through
the lateral plate mesoderm
why is sternum unique?***
It comes from parietal lateral plate mesoderm
neurocranium is formed from what two parts
paraxial mesoderm & neurocrest cells
what is viscercanium formed from
neural crest cells only
limb buds derived from what**
parietal lateral plate mesoderm
what week are limb bones and CT formed
6-8
what is the last thing to form after bone
arteries and nerves
Myotome is divided into what two things
ventrolateral lip & dorsomedial lip
ventrolaterl lip forms what
msucles in front (limb and torso)
dorsomedial lip forms what
muscles in back
paraxial mesoderm from somite migrate from somatomeres down to what
pharyngeal arches
skeletal muscles of face go through what
pharyngeal arches
do skeletal muscle of torso touch pharyngeal arches
no
what innervate the muscles in the pharyngeal arches
cranial nerves
where is hypomere located
anterior body
by 5th week, dorsomedial myoblasts collect into what region
epimere
by end of 5th week ventrolateral myoblasts develop into what
hypomere muscles of anterior body
dorsomedial myoblasts form what
muscles of dorsal body
dorsomedial myoblasts form what
muscles of dorsal body
in the torso do muscles keep their segmented nature
yes
what forms limb
ectoderm, parietal laterl plate mesoderm, paraxial mesoderm
what is not a part of the limb
endoderm
is endoderm part of the limb
no
before muscles grow out what is there
CT core, bones, then the muscles come in
what is at the end of the primitve rim that sends out signals to tell it to grow and not diffeerentiate
apical ectodermal ridg
what is responsible for proximal-distal length of limg
apical ectodermal ridge
what does AER stand for
apical ectodermal ridge
Why do we all have the thumb on the same side
induction signals from retinoic acid that forms gradient so you know which side of limb to put thumb, etc
what is the importance of retinoic acid
creates gradient so things develop in right spot
lateral has what kind of levels of reinoic acid and why si that important
high, it tells body where to put thumb, pinky, etc.
upper limbs rotate how many degrees and what direction
90 degrees dorsolaterally
common interosseaus does what initially
perfuses entire upper limb bud
what does median artery replace
common interosseus as main arterial supply of hand
what replaces median artery
radial and ulnar
what arteries of upper limb are formed last
deep artery of arm and joint arteries
ischiadic artery starts where
high up in gluteal region
what does ishiadic artery perfuse intiially
entire lower limb
why isnt there direct blood supply of posterior thigh
ishiadic artery supplie and then disappears in adulthood
what does ishiaidic form before regressing
anterior tibial & inferior gluteal & foot anastomosis
what is cardiac smooth muscle formed from
VLPM
do hypomere muscle masses form anterior torso muscles
yes
Apical ectodermal ridge forms what
a structure that forms from the ectodermal cells at the distal end of each limb bud and acts as a major signaling center to ensure proper development of a limb.
what forms lateral medial proximal distal
retinoic acid
What induces the adjacent mesoderm to continue to proliferate and remain undifferentiated in the proximal-distal limb axis?
apical ectodermal ridge (AER)
Mesodermal regions will only differentiate into specific structures when what is gone?
apical ectodermal ridge (AER)
