Follicle

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follicle

[′fäl·ə·kəl]
(biology)
A deep, narrow sheath or a small cavity.
(botany)
A type of dehiscent fruit composed of one carpel opening along a single suture.
McGraw-Hill Dictionary of Scientific & Technical Terms, 6E, Copyright © 2003 by The McGraw-Hill Companies, Inc.
The following article is from The Great Soviet Encyclopedia (1979). It might be outdated or ideologically biased.

Follicle

 

a dry, one-celled, many-seeded, and monocarpel-lary fruit that opens along a ventral suture. The seeds are located along the suture on the edges of the carpel. Follicles are typical of the magnolias; of such members of Ranunculaceae as cowslip, garden columbine, aconite and larkspur; and of some genera of Rosaceae, such as Physocarpus.

The simplest follicles resemble a leaf folded in half lengthwise; the upper part corresponds to a stigma and the stem to a stalk. A large number of follicles may be positioned in a spiral on the axis of a blossom (as in the magnolia) to form a multiple fruit. Other types of fruits developed from follicles: nuts are follicles with a single seed, and beans are follicles with a different form of opening.


Follicle

 

a round, oval, or pear-shaped anatomical structure present in various organs in man and other vertebrates, having varied functions. In mammals egg cells develop within the ovarian follicle, which consists of a group of cells; one of these is the egg cell and the rest are epithelial cells surrounding the egg, first in one layer and then in several. As the follicle matures, spaces between the cells become filled with a clear liquid, and the single-layered primordial follicle is transformed into a mature multi-layered follicle, the Graafian follicle.

The follicle of the thyroid gland secretes thyroglobulin, a precursor of the thyroid hormones. Into the hair follicles, which enclose the hair roots and bulbs, empty excretory ducts of the sebaceous glands. Many lymphatic follicles are located in the mucous membranes of the digestive tract, the respiratory tract, and the urinary tract; for instance, follicles known as peyer’s patches are situated in the mucous membrane layer of the intestine.

The Great Soviet Encyclopedia, 3rd Edition (1970-1979). © 2010 The Gale Group, Inc. All rights reserved.
References in periodicals archive ?
The improvement in the ovarian blood flow and the size of the dominant follicles, which have occurred after the amlodipine administration, could be attributed to eliminating the direct vasoconstrictive effects of excessive androgen present in PCOS cases.
As it is well known that oestrogen reaches its highest concentration in dominant follicles, the concomitant increase in catalase and oestradiol in response to FSH may suggest a role of catalase in follicle selection and prevention of apoptosis.
Lussier, "Gene expression profiling of differentially expressed genes in granulosa cells of bovine dominant follicles using suppression subtractive hybridization," Biology of Reproduction, vol.
Matton, 1991.Decreased superovulatory responses in heifers superovulated in the presence of a dominant follicle. J.
Diameter of the first dominant follicle (p<0.05) and diameter of the dominant follicle on d 14 (p<0.05) were different among the treatments (Table 5).
As these mature, one egg should be released at ovulation but for some women with PCOS, hormonal imbalances inhibit the development of a dominant follicle so that all eggs mature and no dominant egg is released.
This dominant follicle then ruptures and releases the egg.
In an ordinary cycle, one follicle, known as the dominant follicle, matures to release an egg, while the rest of the eggs produced in that cycle will die.
These programs are based on combinations of hormones such as GnrH and [PGF.sub.2[alpha]] in the case of the Ovsynch and Cosynch protocols, which synchronize the emergence of a new follicular wave, cause luteal regression, and synchronize the final development and ovulation of the dominant follicle. Other programs for estrous or ovulation synchronization might also incorporate the use of intravaginal inserts containing progesterone.