Vessels, Nerves, Pruritus Flashcards
Describe the vascular supply to the non-primate epidermis and the structures supplied.
o Deep plexus: level of dermis-subcutis, supplies subcutis, lower portions of follicles, apocrine glands
o Middle plexus: level of sebaceous glands. supplies mid follicle, arrector pili muscles, sebaceous glands
o Superficial plexus: just below epidermis. supplies infundibulum and epidermis
List the functions of the blood vessels in the skin.
o Provide oxygen and nutrients to tissue o Rapid delivery of leukocytes to sites of inflammation o Temperature regulation o Blood pressure regulation o Wound repair
What portion of the superficial vasculature is the most physiologically active?
Post capillary venules
• Express TLRs and CD32 (FcγRIIa)- binds IgG → type III HS
• Location of inflammatory cell migration into tissue through gaps in endothelial cells
• Responsive to histamine (H receptors)
• Increase PAR-2 → leukocyte rolling and adhesion
What are veil cells? What anatomic feature regarding their location differentiates them from pericytes?
Unlike pericytes which are incorporated into the vessel wall, veil cells are entirely external to the wall. Veil cells surround all microvessels. Express: glycoprotein 1bα, Von Willebrand factor receptor, Factor XIIIa
The expression of Factor XIIIa indicates veil cells are a component of the dermal dendrocyte system
What are pericytes?
Pericytes are contractile cells oriented parallel to arterioles and venules on dermal side of vessels.
Most abundant at junction of arterioles and capillary loops. Use actin and myosin like fibers to regulate capillary blood flow. Involved in transport across blood brain barrier, involved in regulation of vascular permeability.
How do lymphatic vessels differ from blood vessels?
- have wider and more angular lumen
- are more flat and more attenuated endothelium
- have no pericytes
- have no RBCs
- are negative for vWF
