Skin Flashcards
Functions of the skin
- protection
- homeostasis
- sensory
- endocrine
Protection
Barrier, immunologic
Homeostasis
Fluid, thermoregulation, excretory
Layers of the skin
- epidermis: epithelial layer
- dermis: underlying connective tissue
- subcutis: panniculus, hypodermis
Epidermal derivatives
Adnexa: extra structures - hair - nails - hooves - glands Derived from the stratum basale of the epidermis and embedded in the dermis
Epidermis
- Stratified squamous epithelium (keratinocytes)
- Melanocytes (pigment)
- Langerhans’ cells (antigen presentation)
- Merkel cells (sensory)
Keratinocytes
Matured cells that have lost their nucleus become keratin debris at the top
How many pigments do mammals produce?
1, black
Epidermis Appendages
- hair
- glands
- nails/hooves
Epidermal appendages are also called ____
Adnexa
Types of skin glands
- Sweat (eccrine, apocrine)
- Mammary
- Sebaceous (sebum)
Can you tell nails and hooves apart histologically?
No, both are keratinized structures
What are glands lined by?
Cuboidal epithelium
Layers of the epidermis
- S. corneum
- S. lucidum: not present in non-human mammals
- S. granulosum: see granularity in the cytoplasm
- S. spinosum: start to see spaces
- S. basale (germinativum): layer on the basement membrane
Strata vs stratum
Strata: 5 layers of the epithelium
Stratum: 1 layer
Dermis
- Hemidesmosomes
- Dermal papillae (epidermal rete ridges)
- Dermal ridges (thick skin)
- Papillary and reticular layers
Deep rete ridges
Increases interface between dermis and epidermis
- occurs in areas of wear and tear
Subcutis/hypodermis
- Loose reticular connective tissue
- Adipose connective tissue
Where do you give sub q injections?
In the loose reticular connective tissue
- want to go past the dermis into the subcutis
