Anatomy And Physiology

Structure and Function of the Lungs



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Everyone is familiar with the basic functions of the lungs. They allow you to breathe, it's that simple. The primary structure is also well known, there are two of them - one on the right and one on the left. But the details of the structure and function of the lungs are somewhat more complicated. The lungs are essential organs in the respiratory system, and also play a minor role in some other bodily functions. This article will look at both the structure and function of the lungs.

The structure of the lungs

As you are likely well aware, everyone has two lungs - a right and a left. It is not as well known that the right and left lung are not identical to each other. The lungs are large cone shaped organs which sit on either side of your heart. The apex of the lungs reach as high as your first rib, which is located approximately behind your collarbone (clavicle). The base of the lung reaches as low as the lowest rib you are able to feel under your chest.

The space between the right and left lung it is an area known as the mediastinum. The mediastinum carries many important organs, including the heart.

In broad terms, the respiratory system contains two primary zones - the conducting zone and respiratory zone. The conducting zone consists of the airways through which air travels and consists of the trachea, bronchi, and the parts of the lungs. The respiratory zone is the location where oxygen and carbon dioxide are transported into and out of the bloodstream. Lungs contain elements of both the conducting and the respiratory zones.

Starting in the windpipe, also known as the trachea, the conducting zone then breaks into the two major bronchi (one of which goes to each lung). The bronchi then divide into smaller named bronchi. These named bronchi split in to bronchioles as they go deeper in to the lungs. The bronchioles been divide further to become terminal bronchioles.

Terminal bronchioles will then divide again, becoming respiratory bronchioles. These lead directly to alveolar ducts, and then finally to the alveoli. The alveoli
are the microscopic structures where oxygen and carbon dioxide are exchanged into and out of the bloodstream. They are the functional units of the lungs. If you were to lay out the surface area of all the
alveoli within the lungs, they would cover approximately 65 to 70 m. That's an area roughly a third the size of a tennis court.

As mentioned previously, the right and left longs are not identical to each other. The right lung is slightly larger than the left. The left lung must be smaller in order to take room for the heart. The lungs are broken into smaller functional units called lobes. The right lung has three lobes, and the left lung has two lobes.

The three lobes of the right long are named - upper, middle, and lower. Not very creative, but appropriate. The upper lobe in the middle lobe are separated by a gap known as the transverse fissure. The middle lobe and the lower lobe are separated by a space known as the oblique fissure.

The left lung contains two lobes - the right and left. They are separated by gap referred to as the oblique fissure.

The function of the lungs

Lung function (also referred to as long physiology) is extremely complex. In this article it is only possible to provide a mere outline of the proper functioning of the lungs.

The most well-known and important function of the lungs is to provide a person with oxygen. Oxygen is necessary for a wide variety of metabolic functions within your body. Without a proper oxygen supply, a person will die within minutes.

Another important aspect of lung function is to allow the body to rid itself of excess carbon dioxide. Carbon dioxide is a waste product produced in many metabolic functions of the body. If your lungs were unable to blowoff carbon dioxide, it would accumulate in your body and rapidly cause significant damage.

The process of the inhaling and exhaling air is a concept known as ventilation. The ability of oxygen and carbon dioxide to defuse into and out of the lungs is a process known as perfusion. It is necessary for both ventilation and perfusion to take place in order for the lungs to be functioning properly. There are a wide range of diseases which can limit one or both of these processes.

Doctors have a wide range of different testing parameters available to assess the proper functioning of the lungs. A concept known as total lung capacity (TLC) is a commonly used measurement of a person's ability to inhale and exhale air. Total lung capacity is made up of many factors and depends on a person's age, weight, gender, and even environmental aspects such as smoking history.

The long has a few very important and less well-known functions as well. The lungs are responsible for converting an enzyme known as angiotensin I into an enzyme known as angiotensin II. The angiotensin enzymes play an important level in the regulation of blood pressure.

The lungs play a key role in regulating the acidity of the blood. It is very important for blood to maintain an acidity, also referred to as pH, within a very narrow range. Carbon dioxide concentrations in the blood are a key factor in determining the pH of your blood. Because your lungs are responsible for regulating the amount of carbon dioxide in your body, they are directly responsible for helping to maintain the proper pH within your bloodstream. If you blood becomes too acidic, you will begin to breathe more rapidly attempting to remove excess carbon dioxide from your bloodstream. This will compensate for the low pH and bring it back to normal. If you saw the old movie, The Andromeda Strain, this element of lung physiology played an important role in solving the mystery in the film.

It is important to note that this article is not intended to be a comprehensive overview of long structure and function. The structure and function of the long can fill entire chapters within the medical textbooks. consider this to be merely a simple outline.

More about this author: Erich Rosenberger M.D.

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