SLMHC Cardiac Education & Rehabilitation Patient Education Workbook
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Cardiac Education & Rehabilitation | Sioux Lookout Meno Ya Win Health Centre
Session 4A: How Does the Heart Work?
Your heart
The heart is a hollow, muscular organ located
between the lungs and underneath the
breastbone. It sits slightly to the left, and is
about the size of your fist. Your heart is a
muscle that pumps more than 100,000 times
per day, bringing oxygen-rich blood and
nutrients to your entire body through arteries
and veins. Blood also takes away waste
products and carbon dioxide to be removed
from the body.
Anatomy of the heart
Your heart is divided into four sections (or chambers):
Two at the top
o
Called the left and right atria
o
The atria receive blood from veins
Two at the bottom
o
Called the left and right
ventricles
o
The right ventricle
pumps blood from the
heart to the lungs to
pick up oxygen.
o
The left ventricle pumps
the oxygen-rich blood
through your entire
body.
A muscular wall (the septum)
separates the right side from the
left.
The left and right chambers are
connected by one-way valves that
open and close with every
heartbeat. Valves ensure blood is
pumped through the heart in one direction.
The heart wall is made up of three layers. The outer layer is called the epicardium. The
middle layer is the actual heart muscle and is called the myocardium. The inner layer of
the heart is called the endocardium. The heart is contained within a sac called the
pericardium.
