Wk 1 Integument Flashcards
3 layers of integument
epidermis
dermis
hypodermis
Layers of epidermis
Stratum corneum
Stratum granulosum
Stratum spinosum
Stratum germinativum/basale
Stratum basale
- Mitotically active?
- Protein synthesizers?
- What important protein is synthesized?
- mitotically active
- free ribosomes/polyribosomes, little rough ER
- keratin type intermediate filaments
Stratum spinosum
- Mitotically active?
- How does it look and why?
- mitotically active
- looks ‘spiney’ due to retraction where desmosomes are not present
Lipid bodies produced in stratum spinosum
lamellar bodies
Stratus granulosum
- Mitotically active?
- Cell status?
- mitotically inactive
- cells are dying
Stratum corneum
-Mitotically active?
- mitotically inactive
- completely keratinized
Keratohyalin graules
important for keratin-type intermediate filament aggregation
2 types of karatins
hard: hair and nails
soft: epidermis and internal sheath of hair
Psoriasis
increased stratum basale mitotic activity–>increased cell turnover
Pemphigus vulgaris
desmoglian destruction
blistering
Bullous pemphigoid
autoimmune destruction of dermis-epidermis junction
Most numerous epidermal cell type
keratinocytes
Macrophages distributed in epidermis
Langerhans cells
Merkel cells
non-myelinated sensory nerves
Why are there primary and secondary papillae on the epidermis?
to increase surface area and adhesion
Layers of dermis
papillary layer (with papillae) reticular layer
Lines you cut if you’re a surgeon
Langer’s lines
rough estimate of which direction dense irregular CT runs, reduces scarring
Hypodermis composition
loose CT, adipose
Causes variation in skin color
- carotene (yellow)
- melanin (brown)
Cells look like basketballs with fingery projections
melanocytes
How is melanin formed?
- tyrosinase (in melanocytes) synthesized
- tyrosin and L-dopa polymerized into melanin polymer
Weißfleckenkrankheit
melanocyte destruction
vitiligo
Origin of dermal blood supply
rete cutaneum
