Intro To Dermatology Flashcards
What does epidermis originate from
Ectoderm
What does dermis originate from
Mesoderm which induces differentiation of epidermal structures
Superficial strata of epidermis from superficial to deep
Corn Luvers Grow Several Gereens)
stratum corneum
stratum lucidum
stratum granulosum
stratum spinosum
stratum germinativum basal layer
Which layer is only on palms of hands and soles of feet
Stratum lucidum
Which layer has granules of keratohyalin
Stratum granulosum
State which layer has no nuclei or organelles
Stratum corneum
State which layer is joined by desmosomes?
Stratum germinativum → Stratum spinosum → Stratum granulosum → Stratum lucidum (found on palms of hands and soles of feet) → Stratum corneum
Structure of skin in order of layers from epidermis to subcutaneous fat
Epidermis
Basement membrane
Dermis
Subcutaneous fat
What is epidermis composed of
MMMLK
Keratinocytes
Melanocytes
Langerhan cells
Markel cells
Mast cells
What junctions connect keratinocytes
- Tight junctionsRole in barrier integrity and cell polarity
- Adherens junctions- what do they do?Transmembrane structures which engage with actin skeletonFROM POM: master junction that controls formation of all the others
- Desmosomes- what do they do (detail)?anchor keratin intermediate filaments to cell membrane and bridge adjacent keratinocytes to allow them to withstand trauma
- Gap junctions-
Allow cell synchronization,differentiation,cell growth and metabolic coordination
Function of different parts of corneum
- Top layer absorbs solutes
- Middle layer absorbs water to keep skin hydrated
- Bottom layer is a mechanical defence barrier and includes lipids like sterols and fatty acids that are important for this function
How long do cells take to go from the basement membrane to top?
30 days and this is accelerated in skin disease
Melanocytes
dendritic cells which distribute melanin pigment (in melanosomes) to keratinocytes
Same number in different skin types
Langerhans cells
Dendritic cells (have finger like-processes) and are APCs
Merkel cells
Mechanosensory receptors
Basement membrane (dermal-epidermal junction)- what does this structure consist of and what are its (2) roles
- Made up of proteins and glycoproteins like collagens (IV, VII), laminin and integrins
- Roles are cell adhesion and cell migration (esp of immune cells)
Dermis layers
- Papillary dermis- superficial, loose connective tissue, vascular
- Reticular dermis- deep, dense connective tissue, forms bulk of dermis
Which 3 substances make up the dermis?
- Proteins- 80% collagen (mainly I and III), 3% elastic fibres- fibrillin and elastin
- Glycoproteins- fibronectin, fibulin, integrins- facilitate cell adhesion and motility
- Ground substance- between dermal collagen and elastic tissue- glycosaminoglycans and proteoglycans- maintain hydration of dermis due to high water binding capacity of hyaluronic acid (60% of dermis weight is water)