THE heart is a muscular organ that serves as a pump that sends blood to every part of your body. The heart is always at work, even when you sleep. If your heart were to stop for any length of time, you would not live, but that doesn't mean the heart never rests. Each "heartbeat" consists of a contracting and relaxing of the heart muscles.
THE heart is a muscular organ that serves as a pump that sends blood to every part of your body. The heart is always at work, even when you sleep. If your heart were to stop for any length of time, you would not live, but that doesn't mean the heart never rests. Each "heartbeat" consists of a contracting and relaxing of the heart muscles.
When the heart contracts, it pumps blood through the blood vessels; when it relaxes, it draws blood in. -
bigsiteofamazingfacts.com; wiki.answers.com; biology-online.org
Heartbeat of life
THE heart is a muscular organ that serves as a pump that sends blood to every part of your body. The heart is always at work, even when you sleep. If your heart were to stop for any length of time, you would not live, but that doesn't mean the heart never rests. Each "heartbeat" consists of a contracting and relaxing of the heart muscles.
THE heart is a muscular organ that serves as a pump that sends blood to every part of your body. The heart is always at work, even when you sleep. If your heart were to stop for any length of time, you would not live, but that doesn't mean the heart never rests. Each "heartbeat" consists of a contracting and relaxing of the heart muscles.
When the heart contracts, it pumps blood through the blood vessels; when it relaxes, it draws blood in. -
bigsiteofamazingfacts.com; wiki.answers.com; biology-online.org