Adult Health Library

Health Library Explorer
A B C D E F G H I J K L M N O P Q R S T U V W X Y Z A-Z Listings Contact Us
A B C D E F G H I J K L M N O P Q R S T U V W X Y Z
Topic Index
Library Index
Click a letter to see a list of conditions beginning with that letter.
Click 'Topic Index' to return to the index for the current topic.
Click 'Library Index' to return to the listing of all topics.

Basic Anatomy of the Heart

About the heart

The heart is the hardest working muscle in the human body. It's located almost in the center of the chest. The adult human heart is about the size of a fist.

At rest, a normal heart rate for adults is 60 to 100 beats per minute. In a well-trained athlete, the resting heart rate can be healthy at a rate of 40 to 60 beats per minute. With exercise, the heart beats faster and the heart rate increases to get more oxygen to the muscles.

How the heart works

  • Front view of female body showing arteries, veins, heart, and lungs with closed circulation system.

    The cardiovascular system is made up of the heart and blood vessels. Its job is to circulate blood throughout your body. The blood brings oxygen and nutrients to the tissues.

  • Cross section of heart showing blood flow and conduction system.

    The heart is made up of:

  • 4 chambers (2 atria and 2 ventricles) that get blue (deoxygenated) blood from the body. They pump out red (oxygen-rich) blood back to it:
    • The atria get blood coming back to the heart.
    • The ventricles pump the blood out of the heart.
  • Blood vessels that include a network of arteries and veins that carry blood throughout the body:
    • Arteries carry blood from the heart to the body tissues.
    • Veins carry blood back to the heart.
  • 4 valves to prevent backward flow of blood:
    • Each valve is meant to allow the forward flow of blood. It prevents backward flow.
  • An electrical system that serves as a natural pacemaker. It also conducts electricity to stimulate the heart muscles to contract. This controls the rate and rhythm of the heartbeat.
Online Medical Reviewer: Daphne Pierce-Smith RN MSN
Online Medical Reviewer: Janet Campbell RN BSN
Online Medical Reviewer: Tara Novick BSN MSN
Date Last Reviewed: 5/1/2023
© 2000-2026 The StayWell Company, LLC. All rights reserved. This information is not intended as a substitute for professional medical care. Always follow your healthcare professional's instructions.
Powered by StayWell
Copyright © The StayWell Company, LLC. except where otherwise noted.
About StayWell | StayWell Disclaimer