Limb Development
Not what you're looking for?
How do arms and legs appear and develop in human embryos?
Purchase this Solution
Solution Summary
The expert determines how arms and legs appear and develops in human embryos. The region involved in early development is determined.
Solution Preview
Limb buds first appear during the end of the 4th week of development (the upper limb buds appear around day 26-27 and the lower limb buds appear around day 27-28). They are simply elevations of mesenchyme covered by ectoderm that grow out of the body wall.
At the apex of each limb bud, there is a thickening of ectoderm called the apical ectodermal ridge (AER). This interacts with the mesenchyme below it in order to initiate growth in the proximal-distal direction (i.e. growth in the length of the limb). Key proteins involved in the initiation of growth are fibroblast growth factors (FGFs) expressed in the AER.
Another region involved in the early growth of the limb is the ...
Purchase this Solution
Free BrainMass Quizzes
Basic Immunology Quiz
Intro to immuno quiz. Covers the basics of immunology and recognition of foreign substances by the body.
The Transfer of Energy in an Ecosystem
This quiz will assess your knowledge of how energy is transferred in an ecosystem and the different levels of trophic organization.
The Plant Body
This quiz will test your knowledge of the anatomy of a common plant.
BioChemistry Basics
This Quiz will test your knowledge of the amino acids used in biological systems
Creating a Birth Plan
Preparing for a birth and want to make sure that you're including all the right information? Use this quiz to get on the right track and check your birth plan knowledge!