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 ?
Thereby it is hypothesized that PTX could decelerate infiltration of leukocytes through thyroid follicles.
The epithelial cells found in the inclusions may have a variety of origins, namely: paramesonephric duct cells, salivary gland cells, breast tissue cells, thyroid follicle cells, squamous epithelial cells and mesothelial cells (Piana et al.
From each exposure concentration, 20 fish were sampled for whole-body thyroid hormone analyses, and a further 10 fish in each exposure group were fixed by immersion in 10% phosphate-buffered formalin for histologic examination of thyroid follicles, taking fish with an even distribution between the triplicate tanks.
Histologically, the sections revealed effacement of the normal ovarian architecture by mature thyroid follicles containing colloid (Fig.
However, the correct diagnosis can be made by the cytologic features of the neoplastic cells and the presence of typical thyroid follicles in most of the cases.
It is due to acute aggravation of thyroid autoimmunity induced destruction of thyroid follicles.
The surgical pathology revealed a cystic lesion with an epithelial lining connected to a thin, fibrous extension to the hyoid bone containing thyroid follicles, indicative of a thyroglossal duct.
The lining of the cyst usually is composed of ciliated columnar and stratified squamous cell epithelium, and thyroid follicles typically are found within the wall.
2: Papillary neoplasm arising in submandibular gland which contained entrapped thyroid follicles.
The thyroid follicles are lined with columnar epithelial cells with basally located round nuclei and relatively dense chromatin; the cytoplasm is granular and eosinophilic (figure 2).
The tumor was partially encapsulated, but in some places the capsule was incomplete and the tumor cells mingled with adjacent thyroid follicles.