ArtsAutosBooksBusinessEducationEntertainmentFamilyFashionFoodGamesGenderHealthHolidaysHomeHubPagesPersonal FinancePetsPoliticsReligionSportsTechnologyTravel

How the Heart Works: Part 2

Updated on December 1, 2013
Source

Electrical Paths through the Heart

When you think of the heart, I'm sure most people don't think of it as a series of electrical currents, but that's half the story when talking about the heart.

Electricity is what causes your heart to pump. A small current travels through, and wherever it runs, it causes a contraction (beat). That's why, for certain abnormal heart rhythms, you can "shock" somebody out of it.


-The pacemaker of the heart is the SA node. This is in the top corner of the heart.

-The top part of the heart is divided into 2 chambers, called the left and right atria.

-The middle of the heart that connects the electricity from the top to the bottom is called the AV node.

-The bottom of the heart is divided into 2 chambers, the left and right ventricles.

A Normal Heartbeat

In a normal heart rhythm (called normal sinus rhythm), the electrical pathways follow a very predictable course. For the purposes of this article, I'm going to skip the full terms for everything and use the shorthand.

Your heartbeat starts with a small electrical impulse in the top of your heart. It quickly travels from the top corner (the SA node), through the top portion of your heart (the atria), causing it to beat, pushing blood down into the bottom part of your heart (the ventricles). The electric impulse moves very quickly, too quickly for an efficient heartbeat. So after it causes the top part to beat, it slows down just a little while traveling to the bottom. This allows the blood to flow down from the top of the heart to the bottom. It then spreads through the bottom part of the heart, completing the heartbeat.


-Rhythm changes occur with any disruption of the electrical pathways.

-Afib has too many impulses from the top part of the heart.

-Blocks are caused by impulses not traveling through the middle of the heart appropriately.

How does an Abnormal Rhythm (arrhythmia) Happen?

OK, so we've covered the normal electrical pathways of the heart, but these can be interrupted. The most common disruption is a PVC. A PVC is just referring to the ventricles getting a little excited and beating early, and these typically don't affect a person.

However, more serious heart rhythms can occur. Another, rather common, arrhythmia is called afib. In afib the top part of the heart, for whatever reason, has become too excited. You have impulses starting from all over, so you don't have a true beat. Instead, with so many impulses from so many different places, the top half of the heart just kind of quivers.

There are also "blocks" that can occur. This simply means that the impulse coming from the atria are being blocked to some degree in the middle part of the heart, where the electrical impulse slows down. It could just be getting slowed down too much, or the impulse could be completely blocked and not travel to the ventricle. Some of these require a permanent pacemaker.

But, all isn't lost in these situations. Every portion of your heart has the ability to generate an impulse. If the regular pacemaker fails, the middle of your heart can generate the impulse.. but it's not quite as good as the top. A normal heart rhythm has 60-100 beats per minute (bpm). If your AV node is producing the impulse, it's normal is 40-60 bpm. And, should it fail, the bottom part can generate the impulse... at 20-40 bpm.

I hope this has helped you understand a little about the heart!

Comments

    0 of 8192 characters used
    Post Comment

    • chelseacharleston profile image

      chelseacharleston 6 years ago

      Certainly informative! The heart kind of amazes me. And after watching Flatliners the other night, the added depth in your hub captured me. Thanks!

    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)