Structure and function of skin Flashcards
From what embryological layer is the skin epidermis from?
Ectoderm
From what embryological layer is the dermis formed from?
Mesoderm
From what embryological layer are melanocyte cells from?
The neural crest
What describes the growth pattern of skin?
Blashkos lines
What kind of epithelium is the epidermis?
Stratified squamous
What is the most numerous cell in the epidermis?
Keratinocytes
How long on average does it take cells to migrate through the epidermis from the basement layer?
28 days
What happens when the time for cells to migrate up through the epidermis greatly increases?
Psoriasis
What are the four layers of the epidermis (from bottom to top_
- Basal layer
- Prickle cells
- Granular layer
- Keratin layer
What layer connects the epidermis to the dermis?
The basal layer
What type of cells dominate the prickle cell layer?
Desmosomes
How does disruption of the prickle cell manifest?
Moist skin
Describe the cells of the granular layer?
No nuclei
Large numbers of lipid granules
What two proteins make up the keratin layer?
Keratin and filaggrin
Where are basal cell carcinomas derived from?
Hair follicle cells
What do melanocytes do?
They convert tyrosine to the melanin pigment (melanin) which is brown
How do melanocytes achieve this pigmentation?
Inside the melanocytes their are organelles called melanosomes. These absorb light and convert it into melanin granules which are then transferred to keratinocytes through dendrites. When we are in the sun this pre formed melanin spreads out into the surrounding cells to give a tan.
What is the purpose of a tan?
The melanin cap works to protect DNA is the basal cells
What is vitiligo?
An autoimmune disease in which there is a loss of melanocytes
What is albinism?
A genetic condition where there is loss of pigment production due to an enzyme deficiency.
What is nelsons syndrome?
An excess of melanins stimulating hormone being produced from the pituitary gland.
What do langerhans cells do?
The constantly scan the epidermis for microbes and present these