ArtsAutosBooksBusinessEducationEntertainmentFamilyFashionFoodGamesGenderHealthHolidaysHomeHubPagesPersonal FinancePetsPoliticsReligionSportsTechnologyTravel

As it happens the renal glomerular filtration? How can it be changed?

Updated on May 30, 2013

The renal system has various functions in the human body. These are: the excretion of degradation products of metabolism, such as urea, creatinine, bilirubin, excretion of exogenous chemical substances such as drugs, food additives and pesticides; regulation of fluid and electrolyte balance, blood pressure regulation, the regulation of acid-basic along with the lungs and body fluids tampons; regulation of red blood cell production and the production of the active form of vitamin D.

Microscopically renal system presents its basic unit the nephron. This has the function of glomerular filtration, tubular reabsorption and tubular secretion.

The glomerular filtrate appears very similar to plasma (however, for example, it is known that the filtrate should not be present proteins). In it contains mainly ions and organic solutes of low molecular weight. Among the most common substances are freely filtered ions Na, K, Cl-and HCO3-. Organic substances such as urea and glucose, amino acids and peptides also have free filtration.

It is estimated that the total glomerular filtration rate in an adult male is equivalent to 180 liters per day. If we imagine that the plasma volume is 3 liters, we can say that the kidneys filter plasma 60 times a day.

The filter fact that huge volume of plasma, enables the kidneys excrete large quantities of residual constituents and regulate the internal environment with great accuracy.

The filtration to occur it is necessary that a barrier is exceeded. This barrier is composed of the glomerular capillary endothelium, a basement membrane, and a single layer of epithelial cells.

The capillary endothelium is perforated by many fenestrae. It is freely permeable to all blood except red blood cells and platelets.

The basement membrane is a mesh acellular gel-like glycoproteins and proteoglycans.

The epithelial cells are called podocytes in the region. This anatomical arrangement allows a large fluid filtration but restricts the passage of large molecular weight proteins.

The filterability of solutes is inversely related to its size. Moreover molecules with negative charges are filtered less easily when compared to the positively charged molecules of the same molecular size. This is because the negative charge of the basement membrane is an important barrier to negatively charged molecules, including plasma proteins. This explains why the non-occurrence of filtration of albumin that although its diameter is enough to pass through the pores of the glomerular membrane, it is not filtered because of its negative charge.

Some renal diseases resulting in the loss of negative charges exist in the basal membrane. Consequently, we have a clinical condition characterized by albuminuria or proteinuria.

Glomerular filtration rate is determined by the sum of the colloid osmotic and hydrostatic forces acting through the glomerular membrane (resulting in effective pressure filtration) and the glomerular capillary filtration coefficient (resulting from the local capillary permeability surface area and filtration thereof).

Modification of Intensity of Glomerular Filtration

Some factors make the glomerular filtration rate (GFR) is amended:

GFR increases with increasing coefficient of the glomerular capillary filtration: This coefficient is typically about 400 times greater than other capillaries in the body. Some diseases can lower the coefficient reducing the number of functional glomerular capillaries (thereby decreasing the surface area renal) or increase the thickness of the capillary membrane. Chronic hypertension uncontrolled and interstitial nephritis are examples of these two mechanisms, respectively.

GFR is changed by increasing or decreasing the hydrostatic pressure in the glomerular capillaries. The hydrostatic pressure is determined by three variables: the pressure (increased blood pressure tends to elevate the hydrostatic pressure and thereby increase glomerular filtration. However, this effect is damped by mechanisms of self-regulation), the resistance of afferent arterioles (with increasing resistance, decreases the hydrostatic pressure and glomerular filtration rate) and the resistance of efferent arterioles (increased resistance with increased glomerular filtration. However if the constriction is severe, there will be an increase colloid osmotic pressure and consequently a reduction in filtration glomerular).

GFR decreases by increasing the hydrostatic pressure in Bowman's capsule: in some disease states associated with urinary tract obstruction, the hydrostatic pressure in Bowman's capsule can increase dramatically causing the reduction in glomerular filtration.

GFR decreases by increasing the colloid osmotic pressure of glomerular capillaries. The increased concentration of plasma proteins produces an increase colloid osmotic pressure which in turn decreases the effective pressure filtration and thereby the intensity of glomerular filtration.

Comments

    0 of 8192 characters used
    Post Comment

    No comments yet.

    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)