Skin Structure and Function 2 Flashcards
In what layers of the skin are melanocytes found?
Basal and suprabasal
In what parts of the skin are Langerhans cells found?
Prickle cell layer, dermis and lymph nodes
In what part of the skin are merkel cells found?
Basal layer
When do melanocytes migrate from the neural crest to the epidermis?
During the first 3 months of foetal development
What organelles do melanocytes contain?
Melanosomes
What do melanosomes do?
Convert tyrosine (amino acid) to melanin pigment
What are 2 types of melanin and what colour are they?
Eumelanin (brown or black)
Phaeomelanin (red or yellow)
Different combinations of these give different hair colours)
What happens to melanin produced in melanosomes?
Melanin is sent in packages (melanin granules) to surrounding keratinocytes through the melanocyte limbs (dendritic processes) where it absorbs light (neutral density filter)
Form protective melanin caps over the nucleus protecting the DNA in basal cells
What is another name for full melanosomes?
Melanin granules
What causes a tan when we go into the sun?
An increase in the melanin produced
What is the origin of langerhans cells?
Mesenchymal origin - bone marrow
What is the function of langerhans cells?
Antigen presenting cell - pick up antigen in skin and circulate to lymph nodes via lymphatic system
What is the name(s) of the characteristic organelle found in Langerhans cells?
Birbeck granules
Also called racket organelle
Where in basal layer are merkel cells found?
Between keratinocytes and nerve fibres
What is the purpose of merkel cells?
Act as mechanoreceptors
What makes up the pilosebaceous unit?
Hair shaft
Hair follicle
sebaceous gland
erector pili muscle
What type of muscle is the erector pili muscle?
Smooth
Parts of the hair shaft from outside in?
Cuticle
Cortex
Medulla
What is the name of the part of the pilosebaceous unit that produces hair?
Hair follicle
What is the name of the structure at the base of the hair follicle?
papilla of hair follicle