- 1. A more or less spherical mass of cells usually containing a cavity. 2. A crypt or minute cul-de-sac or lacuna, such as the depression in the skin from which the hair emerges. SYN: folliculus [TA]. [L. folliculus, a small sac, dim. of follis, a pair of bellows]- aggregated lymphatic follicles of small intestine SYN: aggregated lymphoid nodules of small intestine, under nodule.- aggregated lymphatic follicles of vermiform appendix SYN: aggregated lymphoid nodules, under nodule.- atretic ovarian f. a f. that degenerates before coming to maturity; great numbers of such atretic follicles occur in the ovary before puberty; in the sexually mature woman, several are formed each month. SYN: corpus atreticum.- growing ovarian f. a f. having several layers of proliferating follicular cells surrounding the ovum, but separated from it by an extracellular glycoprotein layer (zona pellucida).- hair f. [TA] a tubelike invagination of the epidermis from which the hair shaft develops and into which the sebaceous glands open; the f. is lined by a cellular inner and outer root sheath of epidermal origin and is invested with a fibrous sheath derived from the dermis. SYN: folliculus pili [TA].- Lieberkühn follicles SYN: intestinal glands, under gland.- lingual follicles SYN: folliculi linguales, under folliculus.- luteinized unruptured f. a f. that has undergone luteinization without prior rupture; once thought to cause infertility but now believed to occur equally often in fertile and infertile women.- mature ovarian f. a f. ready for ovulation; in the human ovary its antrum attains a diameter of 6–8 mm and presents a surface bulge; a first maturation (meiotic) division of the ovum usually occurs just prior to the rupture of the f..- multilaminar primary f. a primary ovarian f. with two or more layers of cuboidal follicular cells investing the oocyte.- nabothian f. SYN: nabothian cyst.- primary ovarian f. an ovarian f. before the appearance of an antrum; marked by developmental changes in the oocyte and follicular cells so that the latter form one or more layers of cuboidal or columnar cells; the f. becomes surrounded by a sheath of stroma, the theca. SYN: folliculus ovaricus primarius.- primordial ovarian f. a f. in which the primordial oocyte is surrounded by a single layer of flattened follicular cells.- solitary follicles SYN: solitary lymphatic nodules, under nodule.- splenic lymph follicles small nodular masses of lymphoid tissue attached to the sides of the smaller arterial branches. SYN: folliculi lymphatici lienales, malpighian bodies, malpighian corpuscles (2), malpighian glands, malpighian nodules, splenic corpuscles, splenic lymph nodules.- unilaminar primary f. a primary ovarian f. with a single layer of cuboidal follicular cells investing the oocyte.- vesicular ovarian f. a f. in which the oocyte attains its full size and is surrounded by an extracellular glycoprotein layer (zona pellucida) that separates it from a peripheral layer of follicular cells permeated by one or more fluid-filled antra; the theca of the f. develops into internal and external layers. SYN: antral f., folliculus ovaricus vesiculosus, graafian f., secondary ovarian f., vesicular f..
* * *fol·li·cle 'fäl-i-kəl n1) a small anatomical cavity or deep narrow-mouthed depression esp a small simple or slightly branched gland: CRYPT2) a small lymph node3) a vesicle in the mammalian ovary that contains a developing egg surrounded by a covering of cells: OVARIAN FOLLICLE esp GRAAFIAN FOLLICLEfol·lic·u·lar fə-'lik-yə-lər, fä- adj
* * *n.1. (in anatomy) a small secretory cavity, sac, or gland, such as any of the cavities in the ovary in which the ova are formed. See also Graafian follicle, hair follicle.2. (in ophthalmology) any of the smooth translucent elevations of the conjunctiva produced by an immune response. They are usually associated with viral inflammation.• follicular adj.
* * *fol·li·cle (folґĭ-kəl) 1. a sac or pouchlike depression or cavity; see also folliculus. 2. lymphoid nodule.
Medical dictionary. 2011.