How a Healthy Heart Works
A healthy heart is a strong, hollow muscle that pumps blood throughout the body. It is only about the size of a clenched fist and weighs about a pound.
Heart Location in the Body
Every part of the body — even the heart muscle — needs oxygen and nutrients.
- Blood carries oxygen and nutrients to every part of the body.
- Blood vessels direct the flow of blood throughout the body. (Healthy blood vessels are flexible and smooth.)
- Blood vessels that carry oxygen-rich blood to every part of the body are arteries.
- Blood vessels that carry oxygen-poor blood back to the heart are veins.
- The heart is the pump that keeps blood moving (circulating) throughout the body. Each time the heart contracts, it forces blood through arteries.
The heart is a two-sided pump:
- The right side of the heart receives blood from the body that is low in oxygen and pumps it to the lungs. As it flows through the lungs, blood picks up oxygen. This oxygen-rich blood returns to the left side of the heart.
- The left side of the heart pumps this oxygen-rich blood to every part of the body.
The heart has four chambers:
- The chambers in the upper part of the heart (the right atrium and the left atrium) receive blood and pump it into the lower chambers.
- The lower chambers (right and left ventricles) pump blood to the lungs and the rest of the body.
Valves keep blood moving in the right direction:
- The valves that separate each of the chambers open with every heart beat and close between beats.
- They open in only one direction, so that blood flows in one direction and cannot back up.
Coronary arteries carry oxygen-rich blood to the heart muscle itself like every other muscle in the body, the heart muscle needs oxygen-rich blood to keep it healthy. The blood vessels that carry oxygen-rich blood to the heart muscle are called coronary arteries.
- Coronary arteries are located on the outside of the heart.
- Blockages in these arteries can limit blood flow to the heart and cause a heart attack.
(If you are worried about blocked arteries in your heart or other areas of the body, click here to contact a Banner Heart Center imediately.)
The Heart has its Own Electrical System
During each heartbeat, the heart muscle tightens (contracts) and forces blood through blood vessels. Then it relaxes so the heart can fill with blood again. The heart’s electrical system sends impulses that cause the muscle to contract.
- The sinus node is the heart’s “natural pacemaker.” It begins each impulse which causes the upper chambers (atria) to contract.
- From the sinus node, the impulse travels through the AV node, down the bundle branches and to the lower chambers (ventricles), causing these muscles to contract.
- A healthy heart usually beats about 60 to 100 times a minute. During exercise or when you are excited or stressed, the sinus node sends out faster impulses which cause the heart to pump blood faster. Once you relax, your heart rate should return to about 60 to 100 beats a minute.
- You can feel your heartbeat at specific “pulse points” throughout your body. Counting your pulse lets you know how fast your heart is beating (heart rate).
Everyone’s blood pressure varies somewhat from day to day and with exercise or stress. By measuring the amount of pressure in the arteries during and between heartbeats, a gauge can show whether your blood pressure is normal. In general, normal blood pressure is about 120/70, and some evidence shows that less is better.
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