Urethra membranes

Syphilis is a chronic disease caused by the bacterium Treponema pallidum, which results in the formation of lesions throughout the body. The bacteria usually enter the body during sexual intercourse through the mucous membranes of the vagina or urethra. 

Local anesthetics are used extensively on the mucous membranes in the nose, mouth, tracheobronchial tree, and urethra. The vasoconstriction produced by some local anesthetics, cocaine especially, adds a very important advantage to their use in the nose by preventing bleeding and inducing tissue shrinkage. Topical anesthesia permits many diagnostic procedures in the awake patient, and when it is combined with infiltration techniques, excellent anesthesia may be obtained for many... 

The topical application is also used on the mucous membranes i.e. nose, throat, eye, ear, bronchi, rectum, urethra, vagina and rectum. 

This involves considerable art, which must be learned in the clinic. It falls into two divisions (1) surface application to the mucous membranes, especially of the eye, nose, throat, and urethra and (2) injections about nerves, in different parts of their course and distribution, from their spinal roots to their ultimate fibrils. The advantages and disadvantages in comparison with general anesthesia and the selection of the local anesthetic agent also depend on clinical discrimination. Nervous, fearful, and excitable patients often suffer severely from apprehension, which also disposes toward accidents. They may be at least somewhat quieted by sedatives, morphine (0.015 g hypodermically) half an hour before the operation, or by barbiturates. The latter also tend to prevent convulsions. 

On the other hand, an in vitro study using the rabbit bladder membrane revealed that ns increased rapidly during the pre-loading period for the first 60 min, whereas nk remained constant as seen in Fig. 25 [87], but an in vivo study demonstrated that the friction force increased after cytoscopy of the rabbit urethra. The result is shown in Fig. 26. In this study, ten male rabbits were used for imitating cystoscope operation. One of stainless-steel pipes... 

Andersson et al. (1983) studied the electrically induced relaxation of the noradrenaline contracted isolated urethra from rabbit and man. In rabbits, two circular transverse sections, each 4 mm long, were taken from the middle and upper parts of the urethra. Human urethral preparations were obtained from male patients undergoing cysto-urethrectomy en bloc because of bladder cancer. Rings of tissue were taken from the membranous and supra- and infra-collicular parts of the prostatic urethra. 

Teramoto et al. (1997) examined the membrane potential in the proximal urethra of pigs by use of the microelectrode technique. 

Absorption from mucous membranes on topical application varies according to the compound. Those that are well absorbed are used as surface anaesthetics (cocaine, lidocaine, prilocaine). Absorption of topically applied local anaesthetic can be extremely rapid and give plasma concentrations comparable to those obtained by injection. This has led to deaths from overdosage, especially via the urethra. 

Drugs are applied to the mucous membranes of the conjunctiva, nasopharynx, oropharynx, vagina, colon, urethra, and urinary bladder primarily for their local effects. 

Abforption from the mucous membrane is increafed by opium, and Peruvian bark, internally and by blue vitriol externally. Heiice the expe loration in coughs, and the mucous difcharge from the urethra, are thickened and leflened. 

The most serious adverse effect is the Stevens-Johnson syndrome characterized by sometimes-fatal erythema multiforme and ulceration of mucous membranes of the eye, mouth, and urethra. Fortunately, these effects are comparatively rare. 

An anorectal anomaly is usually identified clinically. There may be an anal dimple present on the perineum or there may be an apparently patent external orifice but with a digitally palpable membrane on examination. Meconium may be passed per urethra in boys or per vagina in girls. 

The borders of the anterior compartment are the pubic symphysis ventrally the components of the levator ani muscle laterally (Fig. 1.1b) and the perineal membrane (see Table 1.1) caudally. There is no distinct border between the anterior and middle compartment in the female. The contents of the anterior compartment are bladder and urethra (Fig. 1.1b). 

Fig. l.lla,b. External urethral sphincter (asterisks), a Axial section (400 pm) of a 24-week-old female fetus, embedded in the transverse perineal membrane. x9. b Computer-assisted three-dimensional reconstruction of a female fetus, p o, pubic bone u, urethra... 

The membranous urethra, about 1-2 cm long, passes through the uro-genital diaphragm, which contains the Cowper glands. In this tract the urethra is surrounded by the striate sphincter and the perineal muscles. 

Stenoses due to pelvic fracturing, on the other hand, affect almost exclusively the membranous urethra. They can be easily investigated with retrograde urethrography and voiding cystourethrography, but are difficult to explore with sonourethrography. 

Kaufmann-McKusick syndrome Hydrometrocolpos, transverse vaginal membrane, vaginal septum, postaxial polydactyly, cardiac anomalies, hypospadias Hydroureter, ureteral duplication, ectopic urethra, urogenital sinus, posterior urethral valves AR (236700), mutations in Bardet-Biedl type 6 BBS6 gene... 

Posterior urethral valves consist of abnormal mucosal folds between the urethral wall and the distal end of the verumontanum. The classification established by Young at the beginning of the twentieth century appears questionable from an endoscopic perspective (Dewan et al. 1992). Young had identified three types of valves. Type I was described as a bicuspid valve radiating distally from the posterior edge of the verumontanum to the anterior aspect of the proximal membranous urethra. Type 1 valves are by... 

Cobb s collar (Cobb et al. 1968) is a congenital narrowing of the bulbar urethra with no connection to the verumontanum (Dewan et al. 1994). It was shown that Cobb s collar is frequently associated with tubular or cystic dilatation of Cowper s glands ducts (also called syringocele) (Dewan 1996), both structures arising embryologically from the urogenital membrane area. 

Cobb BG, Wolf JA, Ansell JS (1968) Congenital stricture of the proximal urethral bulb. J Urol 99 629-631 Dewan PA, Zappala SM, Ransley PG et al (1992) Endoscopic reappraisal of the morphology of congenital obstruction of the posterior urethra. Br J Urol 70 439-444 Dewan PA, Keenan RJ, Morris LL et al (1994) Congenital urethral obstruction Cobb s collar or prolapsed congenital obstructive posterior urethral membrane (COPUM). Br J Urol 73 91-95... 

Development of the external genital organs, the urethra, and the anus involve transformation processes of the internal and external cloaca, which are separated by the cloacal membrane in a transverse plane (Stephens 1983a Nievelstein et al. 1998). At 4 weeks the internal cloaca is a single chamber, into which issue the large intestine, the hindgut, the allantois, and the wolffian ducts. 

The term imperforate anus includes all kinds of anorectal malformations from covering of the anus by a thin skin membrane to high anorectal atresia - with or without a fistula, into the urethra or bladder - and to cloacal anomalies in females. It is well known that a high proportion of patients with imperforate anus have this maldevelopment in association with anomalies of one or several other... 

Careful attention must always be given to precise assessment of the urethral morphology in order to detect narrowing of the bulbar urethra (Cobb s collar) (Dewan et al. 1995 Nonomura et al. 1999) and congenital obstructing posterior urethral membranes (COPUM) (Dewan 1993 Dewan et al. 1997). 

Fig. 25.15. Complete disruption of the membranous urethra in an adolescent boy shown by retrograde urethrography (arrow). Note the inflated balloon of the Foley catheter in the fossa navicularis...

Stratified squamous epithelial tissue is a frequently found epithelium in the human body (nasopharyngeal and oral cavities, esophagus, urethra, vagina, cervix, and others). It is a multilayered structure consisting of a layer of actively dividing basal cells anchored to the basement membrane, beneath which one finds connective tissue (stroma). The daughter cells created by the division of the basal cells form the parabasal layer and mature and migrate to the surface layer. 

This muscle lies deep to the perineal membrane, forming a complete cuff of the urethra, just distal to the prostate. Peripheral fibers anchor to the perineal membrane, the inferior pubic rami and the perineal body. 

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