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A membrane or layer of tissue that covers or envelops an organ or other anatomical structure.



(1) In animals, the peripheral layer of skin coverings of ascidians, salpids, and other animals of the subphylum Tunicata, phylum Chordata. The tunica is a thickened cuticle of cutaneous epithelium that is colonized by cells, a unique phenomenon in the animal kingdom. It serves to protect the internal organs.

The tunica is composed of tunicin, a carbohydrate closely related to cellulose. This substance has a gelatinous consistency, which makes possible the implantation in the tunica of cells that migrate from the cutaneous epithelium. In histological structure, the tunica resembles connective tissue with a gelatinous basal substance. Blood vessels may grow into the tunica. In appendicu-larians, the tunica separates from the body as the result of a process that resembles molting, forming a transparent gelatinous or chitinoid membrane, which serves as an outer covering of the animal or which is appended to the animal externally. This structure is adapted to filtering food particles out of seawater.

(2) In plants, one or more external layers of cells of formative tissue (meristem) covering the corpus of the growing point (apex) in the form of a vault. Dicotyledons have as many as five tunicae, while monocotyledons have as many as three.

Cell division in the tunica predominantly occurs anticlinally, or perpendicular to the surface of the organ; hence the surface of the tunica enlarges without change in the number of cell layers. The epidermis is usually formed from the outer layer of the tunica, which corresponds to the dermatogen according to the histogen theory of the German botanist J. von Hanstein; the primary cortex or part of it is formed from the inner layer of the tunica. The tunica-corpus theory was proposed by the German scientist A. Schmidt in 1924. Sometimes only the layers of cells located higher than the rudimentary leaves are called the tunica. The number of layers of the tunica sometimes increases gradually, but always remains a characteristic taxonomical feature of the plant.

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23 Tunica Roadhouse Casino & Caesars Entertainment
The tunica muscularis was made up of two layers of smooth muscles; inner circular and outer longitudinal layer.
Testis was delivered by a separate scrotal incision and tunica vaginalis flap was harvested which was in turn transferred through a subcutaneous tunnel to fistula site:
4,16) In some cases, diffuse tunica involvement complicates surgery, which may preclude sparing the testicle.
Furthermore, TEM indicated the ubieties of TCs in tunica adventitia, intracellular communication between Tps, and vesicles shedding from TCs into the adjacent extracellular matrix.
On the eve of the wedding parents of the groom entertained family and special friends with a lovely candlelit dinner honoring the bride and groom at Tunica RiverPark Museum.
Tunica Elementary sits near a milo field just off of U.
Ultrasound demonstrated multifocal echogenic lesions with intrinsic vascularity confined to the tunica vaginalis.
Conclusion: The normal mean values of total wall thickness and of each of the individual tunica of coronary arterial wall in Pakistani population are lower than those reported in international literature.
After the water receded in Tunica, gamblers continued to flock to Southland, Troy Keeping, its president and general manager, told Arkansas Business last week.
Mesothelioma of the tunica vaginalis occurs in middleaged to elderly men (mean, 53.