Limb and Vertebrae Development (Anatomy) Flashcards
Explain the development of the limb
- Limb bud → Limb
- Forelimb = Upper Limb
- Hindlimb = Lower Limb
- Human embryo Camegie stage 15 (week 5)
- Outgrowth and patterning
- Growth and differentiation
What are the areas of importance in the development of the limb?
- AER = responsible for progressing growth of the limb
-
ZPA = produces Shh (sonic hedgehog) and the concentration gradient determines Ulnar/Radial or Tibia/Fibular axis of limbs
- E.g. low concentration = radial
- high concentration = ulnar
- E.g. low concentration = radial
- PZ = the cells here are rapidly dividing mesodermal cells which ultimately cause elongation of the limb
What happens when AER is removed very early?
Can lead to major disrupted limb development (e.g. NO limbs)
- Thalidomide disrupts signalling hence, affects AER
What happens when AER is removed later?
- Adactyly (missing fingers)
Concentration of cells determining digits explain
- Apoptosis must occur for digits to differentiate from each other
What happens if apoptosis does not occur in the digits?
Digit malformation → syndactyly (webbed digits)
Explain the development of the neural tube
Explain the development of the sclerotome
Left to right
Explain the development of vertebrae
The sclerotome surrounding the notochord
= Become Vertebral Bodies + Intervertebral Discs
What happens to the notochord?
The sclerotome surrounding the notochord
= Become Vertebral Bodies + Intervertebral Discs
What are some vertebral abnormalities embryologically?
- Hemivertebrae → abscent somite
- Fused vertebrae
- Butterfly vertebrae → failure of fusion of vertebrae
What is myogenesis?
Myogenesis is the formation of skeletal muscular tissue, particularly during embryonic development.
What is myogenesis?
Myogenesis is the formation of skeletal muscular tissue, particularly during embryonic development.
