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.

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.

References in periodicals archive ?
Hair follicles and cheek cells were selected as alternative, readily available tissues that could be obtained noninvasively.
The mechanics of RepliCel's technology involve the extraction of as few as 10 to 20 hair follicles from a patient.
When they mixed those cells with mouse follicular inductive dermal cells and grafted them onto the skin of immunodeficient mice, they produced functional human epidermis (the outermost layers of skin cells) and follicles structurally similar to human hair follicles.
Spheres of cultured papillae cells >from human hair follicles successfully produced new human hair
Hair follicles develop when two different types of cells--epithelial and mesenchymal cells--interact with each other.
Folliculitis usually occurs in men, especially around the beard area where hair follicles are damaged by the friction of shaving.
The number of hair follicles per mm area of skin and ratio of hair follicles in different cyclic phases i.
Experts found that adding certain proteins to the skin helped double the number of new hair follicles.
Study leader Dr George Cotsarelis, who co-founded Follica Inc, said, "We've found that we can influence wound healing with Wnts or other proteins that allow the skin to heal in a way that has less scarring and includes all the normal structures of skin, such as hair follicles and oil glands, rather than just a scar.
Valenzuela got involved in his latest battle with the California authorities when he failed to provide hair follicles for drug-testing last month, in accordance with his conditional riding licence.
The American researchers succeeded where others had failed, and isolated stem cells from mouse hair follicles.
Known as the Demodex mite, the bug lives in the hair follicles of 96-98% of people and feeds on oils, hormones, and fluids around the follicle.