1.1 structure and function Flashcards
where am I derived from? (1) epidermis (2) dermis (3) melanocytes
- ectoderm 2. mesoderm 3. neural crest cells
ectoderm (MEAN) - Merkel cell, melanocytes, epidermis, adnexal structure, nerves
mesoderm - langerhan cell, inflamm cells, vessels, fibroblasts
what are the layers of the epidermis
corneum, lucidum (only hands/feet), granular (profilaggrin, cornified envelope), spinosum (ceramide), basale (ornithine decarboxylase)
what are the different types of junctions?
desmosomes - connects epidermis to keratin, includes desmoglien, desmocollin, desmoplakin, plakophilin, plakoglobin, etc
tight junctions - tight seal against water loss in granular layer, includes occludins and claudins
adherens junctions - attaches to actin, includes plakoglobin, beta catenin, alpha catenin
gap junctions - connexons, helps with intercellular communnication
**plakoglobin in adherens and desmosomes
s. granulosum (keratin ___ and _____)
s. spinosum (keratin ___ and _____)
s. basale (keratin ___ and _____)
- keratin 2, 11
- keratin 1,10
- keratin 5, 14
what does ornithine decarboxylase do?
cellular proliferation from basal layer and up; stimulated by various factors including trauma and UV. Inhibited by retinoids, steroids, and vit D
needs CALCIUM??
Where is the cornified cell envelope ?
granular layer
- reinforced by LORICRIN which starts with TRANSGLUTAMINASE 1
**where is the defect? TG1 - lamellar ichthyosis, TG3 - dermatitis herpetiformis
type I keratins (acidic)
type II keratins (basic)
- K9-28, K31-40, chromosome 17
- K1-8, K81-86, chromosome 12
what interleukins do keratinocytes produce?
IL-1/6/8/10/12, TNF alpha (basically a th1 response?)
- what is responsible for the production of melanocytes?
2. the maturation and migration of melanocytes?
- MC1-R, defect responsible for red hair (think increased pheomelanin/eumelanin)
- c-kit, defect a/w piebaldism and mucosal/acral melanoma
what is the difference btw pheomelanin and eumelanin?
pheomelanin (red/yellow), eumelanin (brown/black)
Positive immunostains for langerhan cells?
CD1a, S100, CD207 (**latter is most sensitive and called langerin)
positive immuostain for Merkel cell
CK20+
what is a Merkel cell vs. langerhan cell vs. glomus cell?
Merkel cell - mechanoreceptor of hands, lips, mouth, and hair
langerhan cell - major antigen presenting cell (APC) of the skin
glomus cell - smooth muscle cells which allow for blood shunting from arterioles to venules, seen in hands and feet
the dermis is mainly composed of COLLAGEN
Collagen I (primary collagen), Collagen III (vascular, fetal skin, GI, scars/keloids), Collagen V
dependent on VITAMIN C
**defect in Ehlers danlos (classic EDS defect COL5, vascular EDS COL3, arthrochalasia EDS COL1)
Collagen I/III normal ratio: 5 to 1
Collagen I/III keloid ratio: 20 to 1
what is the dermis composed of (specifically extracellular matrix)?
collagen & elastic fibers surrounded by ground substance (#1 HYALURONIC ACID)