ArtsAutosBooksBusinessEducationEntertainmentFamilyFashionFoodGamesGenderHealthHolidaysHomeHubPagesPersonal FinancePetsPoliticsReligionSportsTechnologyTravel

What Does Blood Do in the Circulatory System?

Updated on May 11, 2013
Red Blood Cells - Pictures courtesy of
Red Blood Cells - Pictures courtesy of
Circulatory System
Circulatory System

The Blood

Blood is the liquid pumped by the heart throughout the body. The cells are produced in the bone marrow.

The chief function of blood is to bring oxygen and nutrients to tissues in the body, and to carry away carbon-dioxide, lactic acid and other waste material. It also transports hormones and other substances between organs and body tissues.

Blood is made up of the following main components:

  • Plasma - This is the fluid of blood. It is mostly water, with about 4% proteins including albumin, as well as antibodies, hormones and blood clotting factors.
  • Red blood cells - These make up most of the blood cells. They contain a red protein pigment called hemoglobin which combines with oxygen so it can be carried around the body. They also contain the proteins which determine blood types.
  • White blood cells - These are part of the immune system, and defend the body against infection.
  • Platelets - These are sacks of blood clotting chemicals.

The Functions of Blood

White Blood Cell Chases Bacteria in Real Life

How Blood Clots

Did You Know ... ?

  • Our red blood cells do not have a nucleus or organelles, which all cells have. So, according to the definition, they are actually not really cells!
  • Most medical terms related to blood begin with hemo- or hemato- (or haemo- and haemato-) which comes from the Greek word haima which means blood.
  • Blood makes up about 7% of our body weight, and over half of that 7% is plasma.
  • Our blood type (or blood group) is determined by substances on the surface of our red blood cells.


    0 of 8192 characters used
    Post Comment

    • profile image

      Justis 3 years ago

      Superbly ilinmluating data here, thanks!

    • profile image

      Rayann 3 years ago

      Essays like this are so important to brdenaoing people's horizons.

    • profile image

      you2 4 years ago

      helps a lot thanks

    • profile image

      Raysia 4 years ago

      This site is amazing!! Thishelps so much with work when I forget my science book.

    • profile image

      me 6 years ago

      thankyou this website was great 4 my science work!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

    • profile image

      juju 7 years ago

      this help a lot... im doing a project on blood and this had a lot of infromation so thanks.

    • fridayonmymind profile image

      fridayonmymind 7 years ago

      Thanks John. You are most welcome!

    • profile image

      John 7 years ago

      This site is absolutely wonderful! Thank you, it was extremely helpful.

    • fridayonmymind profile image

      fridayonmymind 9 years ago

      Thank you very much, Betty, for your encouraging comment! I'm glad this was of interest to you :)

    • profile image

      Betty 9 years ago

      This is a fun and educational site that provides clips from you tube and information. More people should visit and add comments to show their appreciation of the person who put time and effort in this and succeed in greatness. Thank you owner of this website!


    This website uses cookies

    As a user in the EEA, your approval is needed on a few things. To provide a better website experience, 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: ""

    Show Details
    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 or domains, for performance and efficiency reasons. (Privacy Policy)
    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)
    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.
    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)