Urothelium: The epithelial lining of the URINARY TRACT.Urinary Bladder: A musculomembranous sac along the URINARY TRACT. URINE flows from the KIDNEYS into the bladder via the ureters (URETER), and is held there until URINATION.Uroplakin II: A uroplakin subtype that heterodimerizes with UROPLAKIN IA to form a component of the asymmetric unit membrane found in urothelial cells.Uroplakin III: A uroplakin subtype that heterodimerizes with UROPLAKIN IB to form a component of the asymmetric unit membrane found in urothelial cells.Urinary Bladder Neoplasms: Tumors or cancer of the URINARY BLADDER.Carcinoma, Transitional Cell: A malignant neoplasm derived from TRANSITIONAL EPITHELIAL CELLS, occurring chiefly in the URINARY BLADDER; URETERS; or RENAL PELVIS.Urinary Bladder Diseases: Pathological processes of the URINARY BLADDER.Urologic Neoplasms: Tumors or cancer of the URINARY TRACT in either the male or the female.Cystitis: Inflammation of the URINARY BLADDER, either from bacterial or non-bacterial causes. Cystitis is usually associated with painful urination (dysuria), increased frequency, urgency, and suprapubic pain.Uroplakin Ib: A tetraspanin domain-containing uroplakin subtype. It heterodimerizes with UROPLAKIN III to form a component of the asymmetric unit membrane found in urothelial cells.Urination: Discharge of URINE, liquid waste processed by the KIDNEY, from the body.Urinary Tract: The duct which coveys URINE from the pelvis of the KIDNEY through the URETERS, BLADDER, and URETHRA.Ureter: One of a pair of thick-walled tubes that transports urine from the KIDNEY PELVIS to the URINARY BLADDER.Cystitis, Interstitial: A condition with recurring discomfort or pain in the URINARY BLADDER and the surrounding pelvic region without an identifiable disease. Severity of pain in interstitial cystitis varies greatly and often is accompanied by increased urination frequency and urgency.Uroplakin Ia: A tetraspanin domain-containing uroplakin subtype. It heterodimerizes with UROPLAKIN II to form a component of the asymmetric unit membrane found in urothelial cells.Urinary Bladder, Overactive: Symptom of overactive detrusor muscle of the URINARY BLADDER that contracts with abnormally high frequency and urgency. Overactive bladder is characterized by the frequent feeling of needing to urinate during the day, during the night, or both. URINARY INCONTINENCE may or may not be present.Cryoultramicrotomy: The technique of using a cryostat or freezing microtome, in which the temperature is regulated to -20 degrees Celsius, to cut ultrathin frozen sections for microscopic (usually, electron microscopic) examination.Urogenital Neoplasms: Tumors or cancer of the UROGENITAL SYSTEM in either the male or the female.Administration, Intravesical: The instillation or other administration of drugs into the bladder, usually to treat local disease, including neoplasms.Butylhydroxybutylnitrosamine: A substituted carcinogenic nitrosamine.Cacodylic Acid: An arsenical that has been used as a dermatologic agent and as an herbicide.Purinergic P2Y Receptor Agonists: Compounds that bind to and stimulate PURINERGIC P2Y RECEPTORS. Included under this heading are agonists for specific P2Y receptor subtypes.Urethra: A tube that transports URINE from the URINARY BLADDER to the outside of the body in both the sexes. It also has a reproductive function in the male by providing a passage for SPERM.Urodynamics: The mechanical laws of fluid dynamics as they apply to urine transport.Epithelium: One or more layers of EPITHELIAL CELLS, supported by the basal lamina, which covers the inner or outer surfaces of the body.Tetraspanins: A large superfamily of cell surface membrane proteins characterized by their four transmembrane domains. They play a role in a variety of processes such as cellular adhesion and motility. They may be involved in the organization of cell surface MEMBRANE MICRODOMAINS that regulate the activation of LEUKOCYTES.Keratins, Type I: A keratin subtype that includes keratins that are generally smaller and more acidic that TYPE II KERATINS. Type I keratins combine with type II keratins to form keratin filaments.Muscle, Smooth: Unstriated and unstriped muscle, one of the muscles of the internal organs, blood vessels, hair follicles, etc. Contractile elements are elongated, usually spindle-shaped cells with centrally located nuclei. Smooth muscle fibers are bound together into sheets or bundles by reticular fibers and frequently elastic nets are also abundant. (From Stedman, 25th ed)Lewis Blood-Group System: A group of dominantly and independently inherited antigens associated with the ABO blood factors. They are glycolipids present in plasma and secretions that may adhere to the erythrocytes. The phenotype Le(b) is the result of the interaction of the Le gene Le(a) with the genes for the ABO blood groups.Hyperplasia: An increase in the number of cells in a tissue or organ without tumor formation. It differs from HYPERTROPHY, which is an increase in bulk without an increase in the number of cells.Kidney Pelvis: The flattened, funnel-shaped expansion connecting the URETER to the KIDNEY CALICES.Uropathogenic Escherichia coli: Strains of Escherichia coli that preferentially grow and persist within the urinary tract. They exhibit certain virulence factors and strategies that cause urinary tract infections.Cystectomy: Used for excision of the urinary bladder.Microscopy, Electron, Scanning: Microscopy in which the object is examined directly by an electron beam scanning the specimen point-by-point. The image is constructed by detecting the products of specimen interactions that are projected above the plane of the sample, such as backscattered electrons. Although SCANNING TRANSMISSION ELECTRON MICROSCOPY also scans the specimen point by point with the electron beam, the image is constructed by detecting the electrons, or their interaction products that are transmitted through the sample plane, so that is a form of TRANSMISSION ELECTRON MICROSCOPY.Keratin-13: A type I keratin that is found associated with the KERATIN-4 in the internal stratified EPITHELIUM. Defects in gene for keratin 13 cause HEREDITARY MUCOSAL LEUKOKERATOSIS.Urine: Liquid by-product of excretion produced in the kidneys, temporarily stored in the bladder until discharge through the URETHRA.Mucous Membrane: An EPITHELIUM with MUCUS-secreting cells, such as GOBLET CELLS. It forms the lining of many body cavities, such as the DIGESTIVE TRACT, the RESPIRATORY TRACT, and the reproductive tract. Mucosa, rich in blood and lymph vessels, comprises an inner epithelium, a middle layer (lamina propria) of loose CONNECTIVE TISSUE, and an outer layer (muscularis mucosae) of SMOOTH MUSCLE CELLS that separates the mucosa from submucosa.Immunohistochemistry: Histochemical localization of immunoreactive substances using labeled antibodies as reagents.Keratin-20: A type I keratin expressed predominately in gastrointestinal epithelia, MERKEL CELLS, and the TASTE BUDS of the oral mucosa.Urinary Bladder, Neurogenic: Dysfunction of the URINARY BLADDER due to disease of the central or peripheral nervous system pathways involved in the control of URINATION. This is often associated with SPINAL CORD DISEASES, but may also be caused by BRAIN DISEASES or PERIPHERAL NERVE DISEASES.Urinary Bladder Calculi: Stones in the URINARY BLADDER; also known as vesical calculi, bladder stones, or cystoliths.Papilloma: A circumscribed benign epithelial tumor projecting from the surrounding surface; more precisely, a benign epithelial neoplasm consisting of villous or arborescent outgrowths of fibrovascular stroma covered by neoplastic cells. (Stedman, 25th ed)Muscarinic Antagonists: Drugs that bind to but do not activate MUSCARINIC RECEPTORS, thereby blocking the actions of endogenous ACETYLCHOLINE or exogenous agonists. Muscarinic antagonists have widespread effects including actions on the iris and ciliary muscle of the eye, the heart and blood vessels, secretions of the respiratory tract, GI system, and salivary glands, GI motility, urinary bladder tone, and the central nervous system.Rats, Inbred F344Receptors, Purinergic P2X3: A purinergic P2X neurotransmitter receptor involved in sensory signaling of TASTE PERCEPTION, chemoreception, visceral distension, and NEUROPATHIC PAIN. The receptor comprises three P2X3 subunits. The P2X3 subunits are also associated with P2X2 RECEPTOR subunits in a heterotrimeric receptor variant.