Anatomy And Physiology

Anatomy Physiology

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It circulates the body's blood more than 1,000 times a day. It pumps 5,000 to 5,000 quarts of blood per day through 60,000 miles of blood vessels. All of this from a muscular organ the size of your fist The Human Heart.

The heart, a two-barreled, four-chambered pumper that powers your body, is located just a little to the left of the middle of your chest. The septum is a thick wall that separates the two sides of the heart. Each side has a top and bottom chamber. The top chambers are called atria. Their job is to receive all the blood returning from the lungs and body. Think of them as intake stations. The ventricles are bottom chambers which squeeze the blood out to the lungs and body. They're the sendoff stations. But a lot happens in between.

The heart connects the two circulatory systems of your body the pulmonary circulation system whose blood vessels carry blood through the lungs to pick up oxygen and get rid of carbon dioxides and the systemic circulation system which delivers blood to the rest of the body. To re-fuel red blood cells with oxygen and send them on their way again, the heart does an incredible rhythmic dance. Let's follow the pathway of a single RBC (red blood cell) on its journey.

We'll begin just as the RBC has come back from delivering its precious load of oxygen and is entering the heart. If the RBC is returning from the upper part of the body, it will enter through the superior vena cava. If it's returning from the lower body, it will use the inferior vena cava. Both of these large veins empty into the right atrium. It is then pumped into the right ventricle through the tricuspid valve. Valves (tissue flaps) in the heart open and close with switchman precision. If they don't close completely, there can be backflow. Improperly functioning valves produce an extra sound and are called heart murmurs. Most murmurs are benign but some are serious and require heart valve replacement. But on our journey today, everything is working fine.

From the right ventricle, the RBC is pumped through the pulmonary valve into the pulmonary artery on into the lungs. In the lungs, through a complicated process of gas diffusion across permeable membranes, the RBC will give off CO2 and pick up new oxygen. Then the RBC returns via a pulmonary vein into the left atrium, goes through the mitral valve, and into the left ventricle. With a contraction about as hard as you would squeeze a tennis ball, the oxygenated blood is sent into the aorta and on its way to fuel the body with fresh oxygen. The average RBC lives about 4 months and in its lifespan, it will travel more than 950 miles.

There's another non-clinical aspect to how our heart works. It's not by accident that words like heartache, broken heart, heart-throb etc. are in our vocabulary. From the earliest of times, we have identified this beating wonder in our core with our essence of life. When we're in love, fearful, or scared, we can feel it beating faster. When something sad happens, it's not unusual to feel a pang in the chest. We talk about getting to the heart of the matter meaning the core of something, sometimes the heart of ourselves.

We draw hearts to give love, we honor St. Valentine's with red hearts, and even in death, we are sometimes able to give our heart to another to give new life. The heart with its intricate mechanics and spiritual meaning is a lesson to reflect on. In times of trouble or indecision, we are always reminded to listen to our hearts. Good advice

More about this author: Cynthia Wall

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