Dermis Flashcards
What kind of connective tissue is the dermis made of?
Dense irregular connective tissue
What cells reside in the dermis?
fibroblasts, dermal dendritic cells, macrophages, mast cells
Papillary dermis
- immediately underneath the epidermis and follows its undulations
- more cells, looser CT, many capillaries
- primary collagen is vertically oriented Type I collagen
Reticular dermis
- bulk of the dermis
- fewer cells, bigger collagen bundles that are oriented horizontally.
What is the primary collagen types of the dermis?
Type I collagen provides strength
Type III collage provides compliance
What is the clinical significance of the reticular vs the papillary dermis?
Generally:
Skin diseases manifest in the epidermis and papillary dermis.
Systemic diseases manifest in the reticular dermis/subcutaneous tissue.
What is the role of the ECM components in the dermis?
Collagen - strength
Elastin - elasticity and integration
Ground substance - shape (turgidity and support)
What do fibroblasts do?
- most abundant cell type
- responsible for synthesis
- produce and respond to cytokine signals
- has role in wound healing and scleroderma
What is the role of macrophages?
- janitors
- first responders to infections and APCs
- produce and respond to cytokines
- role in sarcodosis and leprosy
What is the role of mast cells?
- located primarily in the papillary dermis around vessels.
- degranulate to release histamine and heparin in response to IgE activation.
- produce an inflammatory response
Dermal dendritic cells
- these ARE NOT LANGERHANS CELLS
- located around blood vessels in papillary and upper reticular dermis
- respond to mast cell activation
- function as phagocytes and APCs
What is the role of Meissner’s corpuscles?
- located in the tips of the dermal papillae
- touch receptors
What is the role of Pacinian corpuscles?
- located in the deep dermis
- look like onions
- pressure and vibration
