Structure and Function of Skin II Flashcards
What joins the dermis and epidermis?
Dermal papillae
Melanosomes are an organelle found in which cell?
Melanocytes
What are the functions of melanosomes?
Convert tyrosine to melanin pigment (either eumelanin or phaeomelanin)
Form a protective cap over the nucleus
What occurs in vitiligo?
Immune cells attack melanocytes causing loss of pigmentation
How is vitiligo cured?
Phototherapy preventing immune cells attacking melanocytes
What occurs in albinism?
The failed production of eumelanin due to a genetic disorder
What occurs in Nelson’s syndrome?
The pituitary produces excess melanin stimulating hormone causing someone to look too tanned
A melanoma is what?
A melanocyte tumour
Where are Langerhans cells found?
At prickle cell level
Dermis and lymph nodes
What are the functions of Langerhans cells?
Pick up antigen in skin and circulate to lymph nodes
What is the name for tennis racket shaped organelles found in Langerhans cells?
Birbeck granules
Where are Merkel cells found?
In the basal layer between keratinocytes and nerve fibres
What is the function of Merkel cells?
Act as mechanoreceptors between skin and brain
Describe the origin of hair
The epidermis grows inward and meets a component of the mesoderm to form a hair papilla
What muscle erects to make hair stand on end?
Arrector pili
What are the three phases of hair growth?
Anagen (growing)
Catagen (involuting)
Telogen (resting)
Most hairs are in which phase?
Anagen
What occurs in alopecia?
The hair cells are attacked by the immune system
What is the term used for much of your hair falling out?
Telogen effluvium
What can cause telogen effluvium?
Pregnancy
Contraceptive implant
