Discovery Science: Earth Anatomy – Respiration and the lungs

Earth Science: Anatomy – Respiration and the lungs

The lungs are vital organs in the human body that provide oxygen required for most metabolic processes. Lungs also discharge carbon dioxide (CO,), a metabolic waste product, which would otherwise poison the body.

The lungs are made up of two main components: the left and the right lungs. They are protected by the rib cage and flank the diaphragm and abdominal cavity. The right lung is divided into three lobes, whereas the left one is slightly smaller as it is divided only into two lobes. The heart is located between the lungs.

This is where the large bronchial tubes (branches of the wind pipe or trachea) and blood vessels enter the lungs. The lungs are lined by a layer of skin called costal pleura which is always covered by a thin film of liquid. This allows for movement of the lungs while they still fit closely against the chest wall. While breathing, the lungs are consequently able to slide along the walls of the chest with minimal resistance and obstruction.

Gas exchange

Inhaled air travels along the wind pipe into the lungs. The wind pipe is a flexible tube that is kept open by the U-shaped cartilage of the trachea. In the upper part of the chest this tube splits into two bronchial tubes, which branch out further inside the lungs. They get smaller as they split so that air can reach all parts of the lungs. The bronchiole end in small sacs that are arranged similarly to grapes, called alveoli.

There are perhaps several hundred million alveoli, and they are sur-rounded by a fine mesh of blood vessels, where gas exchange occurs. This is possible due to the extremely thin gas- permeable wall separating the inhaled air inside the alveoli and the blood inside the vessels. The oxygen concentration inside the alveoli is high while it is low in the blood, which ensures that oxygen can diffuse from the alveoli into the capillaries.

The exchange of carbon dioxide functions in the same way: the carbon dioxide concentration in the blood is high and low in the alveoli. This gas exchange is effective due to the large, approximately 1,080-square-foot (100-m2) total surface of the human lungs.

RESPIRATION AND EXERCISE

After two minutes of exercise the body responds by supplying muscles with oxygen. It adjusts the frequency and depth of breaths according to the activity level to ensure sufficient oxygen intake and carbon dioxide output

At rest adults breathe in and out about 16 to 18 times a minute, which passes about two gallons (10 L) of air through the lungs. During exercise, however, this amount can be much higher. In this case, up to 15 gallons (60 L) of air pass through the lungs per minute since a rising energy demand means arising oxygen demand.

BASICS

SMOKER’S LUNG is a term for a respiratory disease mostly affecting smokers. One effect of this disease is a disrupted gas exchange of the breathing air and the blood due to the tar in tobacco.