Flashcards in Skin Structure and Function Deck (82)
Embryological origin of the epidermis
*Think Epidermis Ectoderm*
Embryological origin of the dermis
Pattern of growth of skin development follows _______ _____ and rashes which may follow this pattern can be a sign of congenital developmental issues
Appendages of the skin may include (4)
The epidermis is made of what form of epithelium?
Stratifies squamous epithelium
4 main layers of epidermis, in order from top to bottom
1. Keratin layer
2. Granular layer
3. Prickle cell layer
4. Basal cell layer
3 cell types which do not originate from the epidermis, but are found there?
2. Langerhans cells
3. Merkel cells
4 Features of the Basal Cell layer
1. One cell thick
2. Small cuboidal cells
3. Lots of intermediate keratin filaments
4. Very metabolically active
4 Features of the Prickle Cell layer
1. Large polyhedral cells
2. Lots of connecting desmosomes
3. Intermediate filaments connecting the desmosomes
4. cells that evolve and produce proteins
4 Features of the Granular Cell layer
1. 2-3 layers of flatter cells
2. keratinohyaline granules containing filaggrin and involucrin
3. high lipid content
4. cell nuclei are lost here
4 Features of the Keratin layer
1. lots of overlapping non-nucleated cells
3. 80% keratin and filaggrin
4. insensitive to pain
Guess the cell type: These cells migrate from the neural crest
Within which layers of the epidermis are melanocytes found?
from the basal layer and above
What type of cells are melanocytes?
pigment producing dendritic cells
What is the role of melanosomes found within melanocytes?
convert tyrosine to melanin
What are the two forms of melanin?
brown or black melanin with protective function. it is found in hair
red or yellow melanin
How do melanocytes protect the keratinocytes?
The melanosomes migrate to the dendrites of the melanocyte and provide a protective kap over the nucleus of the keratinocyte.
What is a mole?
A nest of melanocytes
Where are merkel cells found?
The basal layer between keratinocytes and nerve fibres; they are ubiquitous
Function of Merkel Cells
What is the origin of Langerhans cells?
Where are Langerhans cells found?
From the Prickle cell layer and above, the dermis and the lymph nodes
Function of Langerhans cells
Aid the skin immune system by acting as APCs
**What feature is unique to Langerhans cells?**
**Racket organelles which contain birbeck granules**
This is a common exam question
How does the hair follicle develop?
Initially grows through an epidermal component and then down into the dermis to develop a dermal papilla
Where does pigmentation come from in hair?
melanocytes above the dermal papilla
Where does the hair follicle develop? (embryologically)