Enviado por "CONSULTORIO MÉDICO FLORES BUISSON"- MÁNCORA - PERÚ.- The urinary tract is made up of the kidneys, ureters, bladder, and urethra, and each plays a role in removing liquid waste from the body. The kidneys filter the blood and produce urine; the ureters carry the urine from the kidneys to the bladder; and the bladder stores the urine until it is eliminated from the body through the urethra. A kidney stone is a hard mass developed from crystals that separate from the urine within the urinary tract. Normally, urine contains chemicals that prevent or inhibit the crystals from forming. These inhibitors do not seem to work for everyone, however, so some people form stones. If the crystals remain tiny enough, they will travel through the urinary tract and pass out of the body in the urine without being noticed. Kidney stones may contain various combinations of chemicals. The most common type of stone contains calcium in combination with either oxalate or phosphate. These chemicals are part of a persons normal diet and make up important parts of the body, such as bones and muscles. A less common type of stone is caused by infection in the urinary tract. This type of stone is called a struvite or infection stone. Another type of stone, uric acid stones, are a bit less common, and cystine stones are rare. Ureteral stones are gravel- like collections of various substances within the urinary tract. Stones nearly always form in the kidney , where they may remain without symptoms and do not require treatment. A ureteral stone is usually a stone from the kidney that has moved down into the ureter. In the human female, the urethra is about 1 1/2-2 inches (3-5 cm) long and opens between the clitoris and the vaginal opening, extending from the internal to the external urethral orifice. It is placed behind the symphysis pubis, embedded in the anterior wall of the vagina, and its direction is obliquely downward and forward; it is slightly curved with the concavity directed forward. Its lining is composed of stratified squamous epithelium, which becomes transitional near the bladder. The urethra consists of three coats: muscular, erectile, and mucous, the muscular layer being a continuation of that of the bladder. Between the superior and inferior fascia of the urogenital diaphragm, the female urethra is surrounded by the Sphincter urethae. Somatic innervation of the external urethral sphincter is supplied by the pudendal nerve. The uro-genital sinus may be divided into three component parts. The first of these is the cranial portion which is continuous with the allantois and forms the bladder proper. The pelvic part of the sinus forms the prostatic urethra and epithelium as well as the membranous urethra and bulbo urethral glands in the male and the membranous urethra and part of the vagina in females. Dysuria is the Painful urination describes any pain, discomfort, or burning sensation during urination. pain on urination is a fairly common problem. It is most often caused by an infection somewhere in the urinary tract.

• published: 22 Nov 2008
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