Shared Flashcard Set

Details

Embryology Lower Limb
Embryology Lower Limb
28
Science
04/18/2009

Additional Science Flashcards

 


 

Cards

Term
Where does the lower limb develop?
Definition
Begins with activation of a group of mesodermal cells of the lateral plate mesoderm. Migrate to limb bud and condense along central axis to form vasculature and skeletal components.
Term
Where do the musculature components of the lower limb migrate from?
Definition
Mesoderm from the somites.
Term
What gene do the future limb mesodermal cells express?
Definition
Homebox 3.3 which is expressed before there any hint of limb bud formation.
Term
What function does the Limb mesoderm perform?
Definition
It signals ectoderm at the tip of the limb bud to thicken and form the apical ectodermal ridge (AER)
Term
What function does the Apical ectodermal ridge perform?
Definition
it interacts with underlying mesoderm to promote outgrowth of the limb bud by promoting mitosis and preventing terminal differentaition of mesodermal cells at the tip of the limb bud.
Term
Zone of polarizing activity
Definition
Mesodermal cells located at the base of the limb bud. Directs the organiztion of teh limb bud and patterning of the digits, both of which involve retinoic acid and homeobox gene Hox-4
Term
What cellular process causes digit formation and what layer does it occur in?
Definition
Apoptosis within the AER such that five separate region of AER remain at the tips of the future digits.
Term
What artery gives rise to the axis artery?
Definition
Umbilical artery which ends in a terminal plexus near the tip of the limb bud.
Term
What does the terminal plexus of the Axis artery do?
Definition
It participates in the formation of hte deep plantar arch.
Term
What are the 5 portions of the Axis Artery?
Definition
1. A. Tibial artery 2. P. Tibial artery 3. Inferior Gluteal Artery 4. Proximal part of the Popliteal Artery 5. Distal part of the peroneal artery.
Term
External Iliac Artery derivatives
Definition
1. Femoral Artery 2.Profunda Femoris Artery
Term
What bones are formed from the Lateral Plate Mesoderm?
Definition
Everything south of the border from the Ilium down to the phalanges.
Term
What type of ossification do the bones of the lower limb undergo?
Definition
Endochondral ossification.
Term
Where is the upper limb bud located and where does it migrate to?
Definition
It lies opposite somites L1,L2,L3,L4,L5,S1,S2. Mesoderm from these somites migrate to the limb bud and forms a posterior condensation and an anterior condensation.
Term
Where do the nerves for the lower limb develop from?
Definition
Lumbosacral Plexus
Term
How are the early nerve fibers guided?
Definition
Are guided into the limb bud by local cell biological messages at its base; the muscles themselves do not provide any specific target messages to the ingrowing nerve fibers.
Term
What week do the lower limb buds appear?
Definition
week 4.
Term
How many degres does the lower ilmb rotate?
Definition
90 degrees Medially during weeks 6 to 8 such that the elbow points posteriorly.
Term
Polydactyly
Definition
usually genetically inherited as an autosomal dominant trait resulting in multiple toes
Term
Syndactyly
Definition
Failure of differentiation in which the fingers fail to separate into individual appendages.
Term
When does separation usually occur?
Definition
During the sixth and eighth weeks of embryological development.
Term
Cutaneous Syndactyly
Definition
a condition in which two or more of the fingers or toes are joined together that can involve the bones or just the skin between the digits.
Term
Congenital Clubfoot
Definition
Foot turns inward and points downward. Restrict lower leg outward movement and causes foot to turn inward.
Term
What is the cause of Teratologic Clubfoot?
Definition
Occurs as a part of an underlying neuromuscular disorder, such as spina bifida
Term
Syndrome Complex Clubfoot
Definition
occurs when a child is born with one of a number of genetic disorders. Children with chromosomal abnormalities such as Down Syndrome.
Term
What is the etiology of Positional Clubfoot?
Definition
When clubfoot occurs when an otherwise normal foot is held in a deformed position in utero, and is molded incorrectly. Small uterus, presence of twins and abnormal fetal position have been associated with positional clubfoot.
Term
What are the symptoms of congenital dislocation?
Definition
Reduced movement in the affected side. leg may seem shorter. assymetric. after 3 months of age leg may turn outward or be shorter than the other leg.
Term
What is the treatment of Congenital dislocatino of the hip?
Definition
Early infancy, positioning with a device to keep the legs apart and turned outward will usually hold the hip joint in place.