9 - Cutaneous Vasculature Flashcards
Blood vascular system is lined by a once-cell-thick layer of epithelium-like mesenchymal cells
Endothelium
The endothelium is supported by various mural cells, typically _____ in microvessels and _____ in larger caliber vessels
Pericytes
Smooth muscle cells
Superficial vascular plexus located
Just beneath the epidermal surface
Deep vascular plexus located
Above the boundary between the reticular dermis and the underlying subcutis
Layers of arterioles and venules
Intima
Media
Adventitia
Layers of capillaries and postcapillary venules
Monolayer of fenestrated endothelial cells sitting on a simple basement membrane
Fenestrae of dermal capillary endothelial cells are formed primarily by a protein called ______; used as a marker of microvascular endothelial cells
Plasmalemmal vesicle protein-1 (PV-1)
Y/N: Pericyte cells outnumber endothelial cells in skin microvessels.
No - endothelial cells outnumber pericyte cells
Principal cell responsible for maintaining blood fluidity, and may be altered when needed to actively promote clot formation
Endothelial cell
Key inhibitors of coagulation basally expresses by endothelial cells
Tissue factor pathway inhibitor
Thrombomodulin
Anticoagulant heparan sulfates
Prevents the dramatic increases of the enzymatic activity of factor VIIa on factors IX and X that is catalyzed by tissue factor
Tissue factor inhibitor
Redirects thrombin from cleaving and thereby converting fibrinogen to fibrin to target and activate protein C instead
Thrombomodulin
Activate antithrombin III to function as an inhibitor of thrombin and factor Xa
Anticoagulant heparan sulfates
Most transit takes place across this portion of the superficial vascular plexus
Capillaries
Tight junction are expressed in the
Arterioles and capillaries
The ______ lack tight junctions and express adherens junctions
Postcapillary venules
Vasodilators produced by endothelial cells
Nitric oxide
Prostacyclin
Vasoconstrictors produced by endothelial cells
Endothelin
Angiotensin-converting enzyme
(Vasodilation/Vasoconstriction) is normally dominant
Vasodilation
Skin blood flow
250-300 mL/min
(Nonglabrous/glabrous) skin is subject to reflex thermoregulation by the sympathetic nervous system
Nonglabrous
(Nonglabrous/glabrous) skin contributed to thermoregulation through shunts from the arterial directly in the venous beds
Glabrous
Y/N: Thermosensitivity of the hand is significantly greater than that of the soles
Yes
Estrogen has a (vasodilator/vasoconstriction) function
Vasodilator
Type 1 diabetes: (greater/lesser) skin blood flow relative to healthy control
Greater
Has promising clinical effects in scleroderma, but does not influence vasospasm in Raynaud disease
Bosentan - antagonizing endothelin A and endothelin B receptors
Present with burning pain and vasodilation with erythema of the extremities
Erythromelalgia
Erythromelalgia is caused by mutations affecting
SCN9A gene
Erythromelalgia most severely affects the
Palms and soles
Local sites of inflammation are perfused at a higher level. The principal mediator for this change is an increase in the synthesis of
Prostacyclin
Made within the first 2 hours of acute inflammation and correlates with the onset of neutrophil recruitment
E-selectin
Synthesized in about 6-12 hours of acute inflammation and correlates with the onset of mononuclear leukocyte recruitment
VCAM-1
Sustained expression of _____, although not unique to skin, is generally described as a skin-specific feature of chronic inflammation
E-selectin
In acute dermatitis, endothelial cells express high levels of _____ and moderate amounts of _____
E-selectin and P-selectin
VCAM-1 and ICAM-1
In chronic skin lesions, endothelial cells express moderate amounts of _____ and high amounts of _____
E-selectin
VCAM-1
Psoriatic capillary loops at the turnaround point touch the epidermis
Kissing
In psoriasis, lymphocytes and neutrophils extravasation within the tips of the papillae
Squirting papillae
Endothelial cells arise from angioblasts, which migrate to peripheral tissues and form primitive blood vessels
Vasculogenesis
Mesenchymal cells are recruited into the vessel wall, where they subsequently differentiate into smooth muscle cells and pericyte cells
Vascular remodeling
Circulating endothelial progenitor cells, mesoangioblasts, and multipotent adult progenitor cells contribute to new vessel formation
Adult vasculogenesis
Vascular wall progenitor cells that differentiate info endothelial cells
CD34+/CD31- cells
Stored in the cytoplasms of a variety of cells and are released when cells are injured, acting as “wound hormones”
FGF-1 and FGF-2
Marks the endothelial cells of early arterial vessels
Ephrin-B2
Marks the endothelial cells of early veins
Ephrin-B4
Phases of wound healing
Coagulation
Inflammation
Proliferation
Remodeling
Major source of VEGF during an early healing stage
Macrophage
Tumor and the stroma compartment respond to hypoxia by expressing
Hypoxia-inducible factor
Tumor angiogenesis: splitting of an existing blood vessel in two
Intussusceptive angiogenesis
Tumor angiogenesis: formation of fluid-conducting channels by tumor cells
Vasculogenic mimicry
Tumor angiogenesis: tumor cells migrate along the preexisting vessels
Vessel co-option
Vascular mimicry appears to play a specific role in
Metastatic melanoma
Generates cancer-associated myofibroblasts that stimulate inflammation and fibrosis and augment vascular dysfunction and as a result increase hypoxia
Endothelial-to-mesenchymal transition
One of the driving factors of endothelial-to-mesenchymal transition
TGF-beta
