Skin Structure and Function II Flashcards
What are 95% of epidermal cells?
Keratinocytes
Where are melanocytes found?
Basal layer and above
Where are Langerhans cells found?
Prickle layer in epidermis, as well as dermis and lymph nodes
Where are Merkel cells found?
In basal layer, between keratinocytes and nerve fibres
When do melanocytes migrate and where do they migrate to?
Migrate from neural crest to the epidermis in first 3 months of foetal development
What is the name of the organelles within melanocytes?
Melanosomes
What do melanosomes do?
Convert tyrosine to melanin pigment=eumelanin (brown/black), phaemelanin (red/yellow)
What does melanin do?
It absorbs light and is a natural density filter
Where are full melanosomes transferred to and why?
Transferred to adjacent keratinocyte via dendrites to form a protective cap over nucleus
How does Vitiligo arise?
Autoimmune disease caused by loss of melanocytes
What causes Albinism?
Genetic partial loss of pigment production (melanocytes are blocked)
What causes Nelson’s syndrome?
Melanin stimulating hormone is produced in excess by the pituitary
What is a malignant melanoma?
Tumour of the melanocyte line
What is the origin of Langerhans cells?
Mesenchymal origin-bone marrow
What role do Langerhans cells play in the immune system|?
Antigen presenting cells, pick up antigen in skin and circulate to lymph nodes via lymphatic system
