Review Questions

• What is the function of the epidermis and its appendages (the hair follicles and sebaceous glands)?
  
  
• Where are unipotent adult skin stem cells located? What do they give rise to?
  
  
• Where are multipotent adult skin stem cells located? What do they give rise to?
  
  
• What keratins do proliferative skin cells express?
  
  
• What is a stem cell niche?
  
  
• What techniques were used to purify label-retaining cells from the epidermis and then analyze their mRNA expression profiles?
  
  
• Name two signaling pathways that keep hair follicle bulge cells quiescent?
  
  
• Name a signaling pathway important for activating hair follicle bulge cells?
  
  
• The ?-catenin protein has two distinct functions in the cell. What are they?
  
  
• How do we measure activity of the Wnt signaling pathway within cells?
• Why should we be cautious about using the Wnt signaling pathway as a clinical treatment for inducing hair growth?