Skin and its appendages Flashcards
What cell layer (gastrulation) gives rise to the skin and its appendages?
The non-neural ectoderm
Skin is also called…
Epidermis
What are the ectodermal appendages (i.e. skin appendages)?
hair, whiskers, feathers, scales, nail, teeth, salivary glands, sweat glands, mammary glands
What layers is the skin composed of?
Epidermis (outer most layer), a basal cell layer and the dermis underneath that
What are the main functions of the skin?
Inside out: prevent water loss
Outside in: prevent entry of pathogens and toxins
What cell layer in the skin proliferate? where are the stem- and progenitor cells?
The basal layer
What is the master regulator of epidermal development?
p63
(BMP triggers p63 expression and the commitment to the epidermal fate)
p63 is a transcription factor with many targets.
How does the epithelium grow during embryogenesis?
Both in size, as the embryo grows larger, but also in thickness as the layers become stratified
What is the first morphological sign of a developing skin appendage?
A placode starting to form (mesenchymal cells condense underneath the placode)
How is the location of a skin appendage determindes?
Likely positional cues, i.e. reaction-diffusion model
Give examples of organs that develop via branching morphogenesis
Salivary gland, Lung, Kidney, Mammary gland, Pancreas, Prostate
Which cells are committed and which are multipotent in the mammary glands?
It seems that even the committed cells are plastic, if the tissue has damage, so it is still not clear
What pathway is essential for skin appendage development?
Wnt/beta-catenin. Mutations cause ectodermal dysplasia in humans
What is common for development of all skin appedages
It starts via placode and bud stages, and they share a lot of the molecular regulation
How can adult stem cells be indentified?
Lineage tracing, label retention studies, transplantation.
However all studies have limitations.
