root sheath


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sheath

 [shēth]
a tubular case or envelope.
arachnoid sheath the delicate membrane between the pial sheath and the dural sheath of the optic nerve.
carotid sheath a portion of the cervical fascia enclosing the carotid artery, internal jugular vein, vagus nerve, and sympathetic nerves supplying the head.
connective tissue sheath of Key and Retzius endoneurium.
crural sheath femoral sheath.
dural sheath the external investment of the optic nerve.
femoral sheath the fascial sheath of the femoral vessels.
Henle's sheath endoneurium.
lamellar sheath the perineurium.
medullary sheath myelin sheath.
myelin sheath (nerve sheath) the sheath surrounding the axon of myelinated nerve cells, consisting of concentric layers of myelin formed in the peripheral nervous system by the plasma membrane of Schwann cells, and in the central nervous system by the plasma membrane of oligodendrocytes. It is interrupted at intervals along the length of the axon by gaps known as nodes of Ranvier. Myelin is an electrical insulator that serves to speed the conduction of nerve impulses (see saltatory conduction).
pial sheath the innermost of the three sheaths of the optic nerve.
root sheath the epidermic layer of a hair follicle.
sheath of Schwann neurilemma.
synovial sheath synovial membrane lining the cavity of a bone through which a tendon moves.
tendon sheath a lubricated fibrous or synovial layer of tissue in which the tendon is housed and through which it moves.

root sheath

one of the epidermic layers of the hair follicle: external root sheath is continuous with the stratum basale and stratum spinosum of the epidermis; internal root sheath comprises the cuticle of the internal roots, Huxley layer, and Henle layer.

root sheath

(rūt shēth)
One of the epidermic layers of the hair follicle: external root sheath is continuous with the stratum basale and stratum spinosum of the epidermis; internal root sheath comprises the cuticle of the internal roots, Huxley layer, and Henle layer.
References in periodicals archive ?
Role of direct immunofluorescence on outer root sheath of hair follicle in monitoring disease activity of pemphigus vulgaris.
BrdU-positive cells were observed in the hair follicle outer root sheath, matrix cells of the hair shaft, and the follicle papilla.
In the meantime, the stromal cells tend to differentiate in the direction of internal root sheath.
The majority of black patients with CCCA are women with female: male ratio of about 3:1.34 The hypothesis of pathogenesis is that patients are predisposed to follicular damage because of an anatomic abnormality namely premature desquamation of the inner root sheath.345 All conditions that result in a progressive pattern of alopecia affecting the crown can mimic CCCA these include male and female pattern alopecia lichen planopilaris and even unusual cases of chronic cutaneous lupus erythematosus.
Ultrastructurally, outer root sheath cells had oval nuclei that became progressively flattened moving laterally from the hair cortex, as the cells flattened in the same direction (Figure 4(b)).
KAP, Keratin-associated protein; ORS, outside root sheath; IRS, inner root sheath; CO, cortical layer; MED, medulla layer; FP, follicle papilla.
Each hair with a visible bulb and root sheath was photographed and staged (0, 1, 2, or 3), according to a bespoke system based on the distance of the lower margin of the sheath from the base of the bulb [10].
In addition, orthokeratosis, follicular plugging, wedge-shaped hypergranulosis of the infundibulum, vacuolar changes of the basal layer of the outer root sheath and necrotic keratinocytes are seen.
As we expected, Gn[alpha]s protein was mainly expressed in the root sheath and dermal papilla of hair follicles (Figure 4A and 4B).
DISCUSSION: Pilomatrixomas are of ectodermal origin and arise from the outer root sheath cells of hair follicle.
Expressed in Bud stage, cap stage (enamel knot) and in hertwigs epithelial root sheath for root formation
Exogenous VEGF dose-dependently stimulates cell proliferation, which is mediated by vascular endothelial growth factor receptor 2 (VEGFR-2) through phosphorylation of extracellular signal-regulated kinase (ERK) in human outer root sheath cells and human hair follicle dermal papilla cells (Li et al., 2012a; Magnuson et al., 2012).