theca
/ˈθiːkə
/noun (plural thecae /ˈθiːsiː/)
1A receptacle, sheath, or cell enclosing an organ, part, or structure, in particular:
1.1 Anatomy The loose sheath enclosing the spinal cord.The vertebral foramen houses the theca and spinal nerves....
- The theca contains the cauda equina or nerve roots.
1.2 Zoology A cup-like or tubular structure containing a coral polyp.It is notable that both specimens also display asymmetry in the overall structure of their thecae....
- In the ‘echinoderm’ reconstruction, the theca lies with the convex side upwards and the appendage is interpreted as an anterior feeding arm.
- The theca around the column is smooth, sometimes with weak longitudinal muscles.
1.3 Botany Either of the lobes of an anther, each containing two pollen sacs.As pollinators removed pollen from the thecae, their walls collapsed and the anthers curled down gradually....
- The percentage of thecae that dehisced longitudinally varied greatly among rice varieties.
- Stamens are didynamous, but the yellow anthers occur close together, with their divergent thecae spreading to the outside.
1.4 (also theca folliculi /fəˈlɪkjʊlʌɪ/) Anatomy The outer layer of cells of a Graafian follicle.The term ‘follicle complex’ has been proposed to include the follicle, basement membrane, and the theca, including its blood vessels....
- The follicle is surrounded by a theca, derived from the stromal compartment of the ovary and is always separated from this compartment, throughout development and final oocyte maturation, by a basement membrane.
Derivatives
thecate
- It is a widespread Paleozoic marine taxon that has been interpreted most recently as a tubiculous annelid or other ‘worm’ or as a thecate hydrozoan or scyphozoan cnidarian.
- The results suggest that intensive regenerative nutrient cycling or external nutrient inputs are a necessary precondition for an efficient trophic transfer of the energy stored in blooms of thecate dinoflagellates.
- This is a small thecate dinoflagellate, almost pear-shaped, with a conical anterior end and a round posterior.
Origin
Early 17th century: via Latin from Greek thēkē 'case'.
Rhymes
- physical sign
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- physician-assisted suicide
- physiciancy
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- physicianless
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- physico-