ArtsAutosBooksBusinessEducationEntertainmentFamilyFashionFoodGamesGenderHealthHolidaysHomeHubPagesPersonal FinancePetsPoliticsReligionSportsTechnologyTravel

Bladder

Updated on March 23, 2012

The bladder is hollow muscular sac that serves as a reservoir for urine. Urine is formed continuously in the kidneys and is stored in the bladder until it is eliminated. In the average adult, about 0.9 to 1.4 liters of urine are excreted every day.

Source

General Description

Located in the front section of the pelvis, the bladder is supported and held in place by ligamentous connective tissue. In a man it rests on and is firmly attached to the base of the prostate gland. In a woman it lies just below and in front of the uterus, attached to the cervix (the neck of the uterus) and the front wall of the vagina.

The size and shape of the urinary bladder depends largely on the amount of urine it contains. When empty, it appears as a rounded, deflated balloon, with its inner surfaces flattened against each other. As it fills with urine, the bladder increases in size and becomes pear-shaped. When it is completely filled, the bladder can hold approximately 17 to 18 ounces (500 to 530 ml) of urine.

From each kidney, urine passes into the bladder through a slender 10- to 12-inch tube called a ureter. Each ureter enters the badder at an oblique angle, allowing the musculature of the bladder wall to act as a sphincter around each opening to prevent the flow of urine from backing up into the ureter.

At the very bottom of the bladder is a thick-walled tube, called the urethra, which conveys the urine to the outside. Immediately beyond the bladder, the urethra passes through a sheet of muscle tissue called the urinogenital diaphragm. At the point where the urethra joins the urinogenital diaphragm, it is surrounded by a thick band of tissue known as the external sphincter. In a man, the urethra is about 8 inches long while in a woman it is only about 1 to 1 1/2 inches long. The three openings into the bladder (the two ureters and the urethra) form the three points of an imaginary triangle. The area inside this triangle is sometimes referred to as the vesical trigone.

Structure of the Bladder

The bladder wall consists of three separate layers of tissue. The innermost layer is a mucous membrane that lines the inner surface and is continuous with the membrane that lines the ureters and the urethra. It is a thin membrane, pale pink in color, and it is wrinkled, with many folds.

The next two layers consist of smooth muscle tissue, and the term detrusor muscle is applied to both layers. The innermost layer is a thick circular band of tissue around the bladder, lying transverse to the long axis. At the base of the bladder this muscle tissue forms a dense band around the neck of the urethra. This band is called the internal sphincter. The outer muscle layer is principally longitudinal. When both muscle layers contract, they decrease both the height and the width of the bladder.

Running throughout the layers of the bladder wall are vast networks of lymph and blood vessels. In addition, the bladder is well supplied with both sensory and motor nerve fibers.

Urination

Urination, also called micturition or voiding, is the act of expelling urine from the bladder. As urine accumulates in the bladder, the bladder walls stretch to accommodate this increasing volume. This stretching stimulates sensory nerve fibers in the bladder wall to transmit nerve impulses to the spinal cord. Some of these sensory impulses are then relayed to centers in the brain, where they are interpreted as a desire to urinate.

The act of urination is controlled by both voluntary and involuntary muscles. The voluntary muscle is the external sphincter, which is usually in a relatively contracted state but can be made to relax at will. The involuntary muscle is the detrusor muscle, which is stimulated to contract by impulses from the spinal cord over parasympathetic nerve fibers. These impulses are part of a reflex initiated by the sensory impulses to the spinal cord from the bladder wall.

Diseases of the Bladder

The urinary bladder is susceptible to a variety of diseases and disorders. Its function may also be disturbed by diseases affecting other organs and tissues. For example, diseases of the lower portion of the spinal cord or the nerves leading to or from the bladder may have a marked effect on the frequency of urination.

One of the most common disorders of the bladder itself is cystitis, an inflammation of the bladder usually caused by bacteria. Symptoms of cystitis include increased frequency of urination, sensations of burning during urination, and the passing of cloudy, sometimes blood-tinged, urine. Cystitis is usually treated by the administration of antibiotic drugs such as tetracycline and penicillin.

The bladder is also susceptible to the formation of calculi, or stones, which are hard masses of minerals and salts. Bladder stones may occur singly or in large numbers and sometimes lodge in the opening of the urethra, cutting off the flow of urine. Bladder stones may often be removed with an instrument called a lithotrite, which is inserted into the bladder and manipulated to crush the stones.

Other disorders of the bladder include hernias, fistulas, and malformations of the bladder that are usually present at birth. Cancer of the bladder is relatively rare, occurring mostly in men over the age of 50.

Comments

    0 of 8192 characters used
    Post Comment

    • health advice profile imageAUTHOR

      health advice 

      6 years ago

      I've decided to change the image, and have now "stolen" Bob Smith's photo of a urinal.

      Not sure where humorous context comes into it, seeing that the contents of a bladder is often emptied into a porcelain device. But I did think the title of your photo (Pissers) was cute.

    • health advice profile imageAUTHOR

      health advice 

      6 years ago

      So despite the fact that the image you put here: http://www.sxc.hu/photo/220738 which under the standard restrictions means I don't have to ask for permission or even list you as a credit (though as you've noted, I have given you credit) you still see fit to say I have stolen the content?

    • profile image

      Lonnie Taylor 

      6 years ago

      In some respects I find it amusing that you used my photo without my permission. In others I wish you didn't give me credit. My friends joke that I should send you an invoice. If you had asked I would have gladly let you use it. I'm not asking you to take it down or remove my name, but I do ask that in the future you ask me if it's alright to use my content. Henceforth I shall refer to this article as an example of stolen content with humorous context.

    working

    This website uses cookies

    As a user in the EEA, your approval is needed on a few things. To provide a better website experience, hubpages.com uses cookies (and other similar technologies) and may collect, process, and share personal data. Please choose which areas of our service you consent to our doing so.

    For more information on managing or withdrawing consents and how we handle data, visit our Privacy Policy at: https://hubpages.com/privacy-policy#gdpr

    Show Details
    Necessary
    HubPages Device IDThis is used to identify particular browsers or devices when the access the service, and is used for security reasons.
    LoginThis is necessary to sign in to the HubPages Service.
    Google RecaptchaThis is used to prevent bots and spam. (Privacy Policy)
    AkismetThis is used to detect comment spam. (Privacy Policy)
    HubPages Google AnalyticsThis is used to provide data on traffic to our website, all personally identifyable data is anonymized. (Privacy Policy)
    HubPages Traffic PixelThis is used to collect data on traffic to articles and other pages on our site. Unless you are signed in to a HubPages account, all personally identifiable information is anonymized.
    Amazon Web ServicesThis is a cloud services platform that we used to host our service. (Privacy Policy)
    CloudflareThis is a cloud CDN service that we use to efficiently deliver files required for our service to operate such as javascript, cascading style sheets, images, and videos. (Privacy Policy)
    Google Hosted LibrariesJavascript software libraries such as jQuery are loaded at endpoints on the googleapis.com or gstatic.com domains, for performance and efficiency reasons. (Privacy Policy)
    Features
    Google Custom SearchThis is feature allows you to search the site. (Privacy Policy)
    Google MapsSome articles have Google Maps embedded in them. (Privacy Policy)
    Google ChartsThis is used to display charts and graphs on articles and the author center. (Privacy Policy)
    Google AdSense Host APIThis service allows you to sign up for or associate a Google AdSense account with HubPages, so that you can earn money from ads on your articles. No data is shared unless you engage with this feature. (Privacy Policy)
    Google YouTubeSome articles have YouTube videos embedded in them. (Privacy Policy)
    VimeoSome articles have Vimeo videos embedded in them. (Privacy Policy)
    PaypalThis is used for a registered author who enrolls in the HubPages Earnings program and requests to be paid via PayPal. No data is shared with Paypal unless you engage with this feature. (Privacy Policy)
    Facebook LoginYou can use this to streamline signing up for, or signing in to your Hubpages account. No data is shared with Facebook unless you engage with this feature. (Privacy Policy)
    MavenThis supports the Maven widget and search functionality. (Privacy Policy)
    Marketing
    Google AdSenseThis is an ad network. (Privacy Policy)
    Google DoubleClickGoogle provides ad serving technology and runs an ad network. (Privacy Policy)
    Index ExchangeThis is an ad network. (Privacy Policy)
    SovrnThis is an ad network. (Privacy Policy)
    Facebook AdsThis is an ad network. (Privacy Policy)
    Amazon Unified Ad MarketplaceThis is an ad network. (Privacy Policy)
    AppNexusThis is an ad network. (Privacy Policy)
    OpenxThis is an ad network. (Privacy Policy)
    Rubicon ProjectThis is an ad network. (Privacy Policy)
    TripleLiftThis is an ad network. (Privacy Policy)
    Say MediaWe partner with Say Media to deliver ad campaigns on our sites. (Privacy Policy)
    Remarketing PixelsWe may use remarketing pixels from advertising networks such as Google AdWords, Bing Ads, and Facebook in order to advertise the HubPages Service to people that have visited our sites.
    Conversion Tracking PixelsWe may use conversion tracking pixels from advertising networks such as Google AdWords, Bing Ads, and Facebook in order to identify when an advertisement has successfully resulted in the desired action, such as signing up for the HubPages Service or publishing an article on the HubPages Service.
    Statistics
    Author Google AnalyticsThis is used to provide traffic data and reports to the authors of articles on the HubPages Service. (Privacy Policy)
    ComscoreComScore is a media measurement and analytics company providing marketing data and analytics to enterprises, media and advertising agencies, and publishers. Non-consent will result in ComScore only processing obfuscated personal data. (Privacy Policy)
    Amazon Tracking PixelSome articles display amazon products as part of the Amazon Affiliate program, this pixel provides traffic statistics for those products (Privacy Policy)