theca

American  

[thee-kuh] / ˈθi kə /

noun

thecae plural

1. a case or receptacle.

2. Botany, Mycology.

   1. a sac, cell, or capsule.

   2. a sporangium.

3. Anatomy, Zoology. a case or sheath enclosing an organ, structure, etc., as the horny covering of an insect pupa or the loose membrane covering the spinal cord.

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theca British  

/ ˈθiːkə /

noun

1. botany an enclosing organ, cell, or spore case, esp the capsule of a moss

2. zoology a hard outer covering, such as the cup-shaped container of a coral polyp

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theca Scientific  

/ thē′kə /

thecae plural

1. A case, covering, or sheath, such as the pollen sac of an anther, the spore case of a moss, or the outer covering of the pupa of certain insects.

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Other Word Forms

• thecal
  adjective

Etymology

Origin of theca

1655–65; < Latin thēca, from Greek thḗkē “case, cover,” akin to tithénai “to place, put”

Example Sentences

The release of LH also stimulates the granulosa and theca cells of the follicles to produce the sex steroid hormone estradiol, a type of estrogen.

From Textbooks • Jun. 19, 2013

Supporting granulosa and theca cells in the growing follicles produce estrogens, until the level of estrogen in the bloodstream is high enough that it triggers negative feedback at the hypothalamus and pituitary.

From Textbooks • Jun. 19, 2013

It occurs when the granulosa and theca cells of the tertiary follicles begin to produce increased amounts of estrogen.

From Textbooks • Jun. 19, 2013

FSH stimulates the growth of a tertiary follicle, and LH stimulates the production of estrogen by granulosa and theca cells.

From Textbooks • Jun. 19, 2013

Before the latter plates arose, the stem had developed by the elongation and constriction of the fixed end of the theca, the gradual regularization of the plates involved, and their coalescence into rings.

From Encyclopaedia Britannica, 11th Edition, Volume 8, Slice 10 "Echinoderma" to "Edward" by Various