- In dermatology, a vesicle is a small blister, as on the skin. Vesicles also occur on the mucous membranes, such as the buccal mucosa (the lining of the mouth). Vesicles are less than .5 centimeters in diameter.In anatomy, a vesicle is any small pouch. For example, the seminal vesicles are a pair of pouch-like structures about five cm (2 inches) long located behind the bladder and above the prostate gland that contribute fluid to the ejaculate. The word vesicle comes from the Latin diminutive vesiculum meaning a small bag or bladder.
* * *1. SYN: vesicula. 2. A small (<1.0 cm in diameter), circumscribed elevation of the skin containing fluid. SEE ALSO: bleb, blister, bulla. 3. A small sac containing liquid or gas. 4. A closed structure surrounded by a single membrane. [L. vesicula, a blister, dim. of vesica, bladder]- acrosomal v. a v. derived from the Golgi apparatus during spermiogenesis whose limiting membrane adheres to the nuclear envelope; together with the acrosomal granule within, it spreads in a thin layer over the pole of the nucleus to form the acrosomal cap.- air vesicles SYN: pulmonary alveolus.- blastodermic v. SYN: blastocyst.- cerebral v. each of the three divisions of the early embryonic brain (prosencephalon, mesencephalon, and rhombencephalon). SYN: encephalic v., primary brain v..- cervical v. an abnormally persisting vestige of the cervical sinus or its associated branchial grooves.- coated v. a v. that has its biomembrane coated with the protein clathrin. It is involved in the transport of proteins from one membrane site to another.- lens v. in the embryo, the ectodermal invagination that forms opposite the optic cup; it is the primordium of the lens of the eye. SYN: lenticular v..- matrix vesicles hydroxyapatite-containing, membrane-enclosed vesicles secreted by odontoblasts and some chondrocytes; believed to serve as nucleation centers for the mineralization process in dentin and calcified cartilage.- ocular v. SYN: optic v..- ophthalmic v. SYN: optic v..- optic v. in the embryo, one of the paired evaginations from the ventrolateral walls of the forebrain from which the sensory and pigment layers of the retina develop. SYN: ocular v., ophthalmic v., vesicula ophthalmica.- otic v. one of the paired sacs of invaginated ectoderm that develop into the membranous labyrinth of the internal ear. SYN: acoustic v., auditory v..- pinocytotic v. a v., a fraction of a micrometer in diameter, containing fluid or solute being ingested into a cell by endocytosis. SEE ALSO: pinocytosis.- synaptic vesicles the small (average diameter 30 nm), intracellular, membrane-bound vesicles near the presynaptic membrane of a synaptic junction, containing the transmitter substance which, in chemical synapses, mediates the passage of nerve impulses across the junction. SEE ALSO: synapse.- telencephalic v. paired diverticula arising from the prosencephalon, from which the forebrain develops.
* * *ves·i·cle 'ves-i-kəl n1 a) a membranous and usu. fluid-filled pouch (as a cyst, vacuole, or cell) in a plant or animalb) SYNAPTIC VESICLE2) a small abnormal elevation of the outer layer of skin enclosing a watery liquid: BLISTER3) a pocket of embryonic tissue that is the beginning of an organ see auditory vesicle, BRAIN VESICLE, OPTIC VESICLE
* * *n.1. a very small blister in the skin, often no bigger than a pinpoint, that contains a clear fluid (serum). Vesicles occur in a variety of skin disorders, including eczema and herpes.• vesicular adj.
* * *ves·i·cle (vesґĭ-kəl) [L. vesicula] 1. a small bladder or sac containing liquid; called also vesicula. 2. a small circumscribed epidermal elevation, usually containing a clear fluid; called also blister. Cf. bulla. 3. a small membrane-bound sac, derived mainly from the plasma membrane, Golgi complex, or endoplasmic reticulum, occurring in eukaryotic cells. 4. the swollen end of a conidiophore from which sterigmata are produced.
Medical dictionary. 2011.