What's the difference between sheath and theca?

Sheath


Definition:

  • (n.) A case for the reception of a sword, hunting knife, or other long and slender instrument; a scabbard.
  • (n.) Any sheathlike covering, organ, or part.
  • (n.) The base of a leaf when sheathing or investing a stem or branch, as in grasses.
  • (n.) One of the elytra of an insect.

Example Sentences:

  • (1) The oral nerve endings of the palate, the buccal mucosa and the periodontal ligament of the cat canine were characterized by the presence of a cellular envelope which is the final form of the Henle sheath.
  • (2) Electron microscopic observations of the masseter nerve in the aged cats revealed a disruption of the myelin sheaths and a pronounced increase in collagen fibers in the endoneurium and perineurium.
  • (3) The authors propose three regular procedures with which they are experienced: repair with a large retromuscular nonabsorbable synthetic tulle prosthesis for extensive epigastric eventrations, fillup aponeuroplasty using the sheath of the rectus abdominis associated with a premuscular patch in case of diastasis or of multiple superimposed orifices and suture associated with a small retromuscular auxiliary patch to treat small incisional hernias.
  • (4) Extraction tools included flexible, telescoping sheaths advanced over the lead to dilate scar tissue and apply countertraction, deflection catheters, and wire basket snares.
  • (5) Thirteen soft tissue sarcomas with ultrastructural evidence of nerve sheath differentiation were investigated by immunohistochemistry.
  • (6) This cell population gives rise initially to oligodendrocytes and then to type-2 astrocytes, both of which apparently collaborate in sheathing axons in the CNS.
  • (7) Rabbit antirat T-cell serum (ALS(T)) reacted selectively with the surfaces of lymphocytes in the paracortex of lymph node and in the periarteriolar sheath of spleen, and with thymocytes.
  • (8) After properly fixing the vas deferens with a ring clamp, the surgeon pierces the scrotal skin, vas sheath, and vas deferens in the midline with a curved dissecting clamp held at a 45 degree angle from horizontal.
  • (9) We immunohistochemically examined the expression of Schwann cell-related markers, nerve growth factor (NGF) receptor, S-100 alpha- and beta-proteins, glial fibrillary acidic protein (GFAP), and galactocerebroside (gal C) in 5 malignant schwannomas, 21 benign peripheral nerve sheath tumors, and 4 apparently normal sural nerves.
  • (10) The transversalis fascia of the floor of the femoral canal turns down to form the medial wall of the venous compartment of the femoral sheath, and has the support of the curved edge of the lacunar ligament which effectively bars the femoral canal from entering the thigh.
  • (11) Unique domains of the retinal interphotoreceptor matrix (IPM), termed cone matrix sheaths, are composed largely of chondroitin 6-sulfate proteoglycan in most higher mammalian species.
  • (12) 2ME treatment caused partial solubilization of the sheaths (45% as determined by amino acid analysis), which could be further improved by combining 2ME with SDS.
  • (13) The 6.8F ultrasound balloon catheter was placed percutaneously in the right femoral artery through a 9F sheath.
  • (14) The isolated outer sheath was observed as a triple-layered, closed vesicle carrying a polygonal array by electron microscopy.
  • (15) These data show that the 515 nm absorbance change is not limited to small closed vesicles like grana, but in the presence of suitable electron donors single lamellae of bundle sheath chloroplasts can also be active.
  • (16) An outer sheath was isolated from Treponema phagedenis biotype Reiter by our previously developed method (Masuda, K., and Kawata, T. 1982.
  • (17) Seven tumours were predominantly of blue and spindle-cell, fascicular type, resembling malignant peripheral nerve sheath tumour and at times monophasic synovial sarcoma.
  • (18) Several additional groups of muscle cells of more limited mass and spatial distribution include the vulval muscles of hermaphrodites, the male sex muscles, the anal-intestinal muscles, and the gonadal sheath of the hermaphrodite.
  • (19) The notochord, which is composed of a stack of flat cells surrounded by a connective tissue sheath, elongates dramatically and begins straightening between stages 21 and 25.
  • (20) Under fluoroscopic control a lower polar calix was punctured with 18 G sheathed needle; a guide wire was introduced through the sheet.

Theca


Definition:

  • (n.) A sheath; a case; as, the theca, or cell, of an anther; the theca, or spore case, of a fungus; the theca of the spinal cord.
  • (n.) The chitinous cup which protects the hydranths of certain hydroids.
  • (n.) The more or less cuplike calicle of a coral.
  • (n.) The wall forming a calicle of a coral.

Example Sentences:

  • (1) By 24 hr, rough endoplasmic reticulum in thecal cells increased from 4.2 to 7% of cell volume, while the amount in granulosa cells increased from less than 3.5% to more than 10%; the quantity remained relatively constant in the theca but declined to prestimulation values in the granulosa layer.
  • (2) In the small ovarian follicles, the immunostaining for TGF-beta 1 was present in oocytes, follicle cells, and granulosa and theca cell layers.
  • (3) These results suggest that TGF-alpha is synthesized in the ovary, perhaps in the theca-interstitial compartment.
  • (4) 125I-Labelled OTA consistently labelled the ovarian stroma and the theca interna, but not the corpora lutea, the granulosa cells or the theca externa.
  • (5) This leads, in turn, to triple-layering of the theca interna in follicles of the 2nd resting period.
  • (6) The electron microscopy examinations showed that a large amount of collagen fibers scattered under the albuginea layer and interwove with cells of albuginea and theca externa.
  • (7) The binding sites for human follicle-stimulating hormone were found in three tumors of epithelial origin (serous cystadenoma and mucinous cystadenoma) and in two of sex cord-stromal origin (theca cell tumor and theca-granulosa cell tumor).
  • (8) The purpose of this study was to compare the steroidogenic potential of the granulosa, theca, and medullary tissues from polycystic and normal ovaries.
  • (9) Those cells such as the granulosa cells of smaller follicles, the theca interna cells, the interstitial gland cells, oocytes, peritoneal epithelial cells were entirely negative.
  • (10) A significant increase in thymidine per follicle occurred at 15:00 h on Days 1 and 3 of the cycle from stage 2 (bilaminar follicle) to stage 6 (7-8 layers granulosa cells plus theca).
  • (11) Taken together, these and previous observations reveal fundamental differences in the cellular localization and hormonal regulation of ovarian IGF gene expression in that IGF-II gene expression (unlike IGF-I) is theca-interstitial (rather than granulosa) cell-specific, and is subject to down (as opposed to up) regulation in response to estrogenic stimulation.
  • (12) Marked infolding of both the granulosa and theca tissue in some follicles suggested early luteinization.
  • (13) Cellular localization studies revealed the IGFBP-3 gene to be exclusively expressed in the theca-interstitial rather than the granulosa cell compartment.
  • (14) The acquisition of catecholamine responsiveness was specific to hCG; if theca-interstitial cells were induced to differentiate with either prostaglandin E2 or cholera toxin, then isoproterenol did not enhance androgen synthesis.
  • (15) CR was primarily localized in interstitial gland cells and in theca interna cells but was not found in corpora lutea cells in the ovary during the estrous cycle.
  • (16) Specific LH receptors with common binding properties were detected in both granulosa and theca layers of large preovulatory follicles.
  • (17) The rat perforatorium is the part of the perinuclear theca that underlies the acrosomic system.
  • (18) One to several layers of theca interna cells just beneath membrana granulosa did not demonstrate any immunoreactivity of 3 beta-HSD or that of cytochrome P-450 17 alpha-hydroxylase.
  • (19) To test the possibility that progesterone released by granulosa cells may serve as a substrate for production of androgen in theca cells, specific antiserum was used to adsorb progesterone present in the medium.
  • (20) Very few adrenergic nerve fibres were present in the theca interna of follicles or in the corpus luteum.

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