DD Derm Term and Fxns, Epidermal Struc and diseases Flashcards
Which cells are responsible for Vit D synthesis?
Keratinocytes in the epidermis
- also synthesizes keratin
Which cells are involved in immunologic barriers?
langerhan cells
Which types of cells are involved in pheromones and body odor?
apocrine glands
Keratinocytes
- forms barrier layer,
- synthesize keratin (fibrous protein of skin),
- synth Vit D
- involved in proliferation,
- differentation,
- programmed cell death.
What is skin color variation due to?
Type of melanin produced and distribution of melanosomes
-NOT due to the # of melanocytes
Langerhans Cells:
□ Dendritic cells derived from bone marrow stem cell; found in small #s
□ Participate in cell-mediated immune reactions by behaving as an APC
Layers of the dermis
Papillary layer (loose CT directly deep to the epidermis)
Reticular layer (deeper)
Which dermis layer provides blood supply for the epidermis?
Papillary
- note: reticular layer serves as the pathway of major BVs arranged specifically to facilitate thermoregulation
Meissner’s corpuscles
Pacinian corpuscles
- Where are they found?
- What do they do?
Meissner’s corpuscles
- in papillary layer
- fine/tactile sense touch (fingertips)
Pacinian corpuscles
- in reticular layer
- sense vibration, pressure, and touch (gentitals ahhh yyeeaaaa)
cellular layers of skin
Chinese Ladies Give Superb Backrubs (superficial to deep)
- Stratum corneum
- Stratum lucidum (thick skin only)
- Stratum granulosum
- Stratum spinosum
- Stratum basale
Eumelanin
Pheomelanin
Eumelanin: black-brown pigment
Pheomelanin: yellow-red-brown pigment
Three ways you can get VIt D
- Sun (UVB -> skin)
- Diet (Ergocaciferl aka Vit D2)
- Diet (Cholecaciferol aka Vit D3)
- These are then converted to Calcidiol by the liver
- Calcidiol is then converted to Calcitriol by the kidneys
UVB from the sun gets converted to what?
Cholecalciferol Vit D3
same as the one from the diet
Hemidesmosomes
attach basal cells to the basal lamina of dermal epidermal junction
Desmosomes
attach keratinocytes to each other
Pemphigus Vulgaris
- AutoAntibodies to desmosome proteins
- Epidermis attaches fine to Dermis, but connection between keratinocytes suck
- Skin lesions are flaccid bulla.
- nikolai’s sign (skin peels off)
(that 16 year old kid had it)
Tonofilaments
protein structures that insert into the cytoplasmic side of the plasma membrane of desmosomes
Bullous Pemphigoid
Antibodies to the hemidesmosomes.
Epidermis does not attach to dermis.
Basal keratinocytes
- what are they
- where are they located?
Stem cells of the epidermis
located in the bottom most stratum basalis (germinativum)
How long does it take to renew the epidermis?
28 days
Function of:
Stratum Basalis
Location of some cell attachments
Function of:
Stratum Spinosum
Reinforce the cytoskeleton
note: Synthesis of involucrin and membrane coating granules occurs here
Function of:
Stratum Granulosum
Contain different types of granules (ie: kertohyalin granules containing filaggrin)
What skin layer do cells no longer have nuclei or organelles?
Stratum lucidum if present
Or Stratum corneum
What skin layer is the entire cell filled with keratin?
Stratum corneum
What granules contain the filaggrin precursor? What layer of skin is it in?
Keratohyalin granules contain the filaggrin precursor.
- In Granulosum
What layer does shedding of dead corneocytes occur? What is that called?
Stratum corneum is where Desquamification occurs.
Filaggrin is mutated in what two skin disorders?
Atopic dermatitis
Ichthyosis
