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 It might be outdated or ideologically biased.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 ?
Follicle growth, ovulation, and luteal formation in primates and rodents: A comparative perspective.
BMP15 and GDF9 play a critical role in follicle development, oocyte maturation, ovulation and embryo development (8,9).
Around15-20 slides (every fifth section) were prepared for estimation of follicle count from each ovary.
Many factors regulate hair follicle stem cell quiescence.
Comparison of follicle restored with baseline characteristics: The follicle restored was found significantly associated with age (p-value <0.001) and duration of infertility (p-value 0.026).
However, this approach requires manually merging the stem cells derived from these two different origins under a microscope, making it a challenge to produce the 5,000 or more hair follicle germs (HFGs) required per transplant patient.
While the majority of primordial follicles will die and never complete their development, a small proportion will eventually develop further to become pre-ovulatory follicles.
Their ends are therefore naked like wires stripped at the tips, making it possible for them to directly contact hair follicle stem cells.
However a lack of follicle quantity or number with defects in follicular development in the ovary has become the principal cause of female fertility affecting approximately 1% of women aged under 40 years [13-15].
The mean number of follicles, as affected by diet and age (as well as mean length and area of the proximal follicle in each ovariole), was subjected to a 2-way ANOVA and differences determined by Tukey's test (P < 0.05).