This lubrication reduces friction between the two layers to prevent trauma during breathing, and creates surface tension that helps maintain the position of the lungs against the thoracic wall. This adhesive characteristic of the pleural fluid causes the lungs to enlarge when the thoracic wall expands during ventilation, allowing the lungs to fill with air.
The pleurae also create a division between major organs that prevents interference due to the movement of the organs, while preventing the spread of infection. The burning of a tobacco cigarette creates multiple chemical compounds that are released through mainstream smoke, which is inhaled by the smoker, and through sidestream smoke, which is the smoke that is given off by the burning cigarette.
Second-hand smoke, which is a combination of sidestream smoke and the mainstream smoke that is exhaled by the smoker, has been demonstrated by numerous scientific studies to cause disease. At least 40 chemicals in sidestream smoke have been identified that negatively impact human health, leading to the development of cancer or other conditions, such as immune system dysfunction, liver toxicity, cardiac arrhythmias, pulmonary edema, and neurological dysfunction. Furthermore, second-hand smoke has been found to harbor at least compounds that are known to be toxic, carcinogenic, or both.
Some major classes of carcinogens in second-hand smoke are polyaromatic hydrocarbons PAHs , N-nitrosamines, aromatic amines, formaldehyde, and acetaldehyde.
Tobacco and second-hand smoke are considered to be carcinogenic. Exposure to second-hand smoke can cause lung cancer in individuals who are not tobacco users themselves. It is estimated that the risk of developing lung cancer is increased by up to 30 percent in nonsmokers who live with an individual who smokes in the house, as compared to nonsmokers who are not regularly exposed to second-hand smoke.
Children are especially affected by second-hand smoke. Children who live with an individual who smokes inside the home have a larger number of lower respiratory infections, which are associated with hospitalizations, and higher risk of sudden infant death syndrome SIDS. Second-hand smoke in the home has also been linked to a greater number of ear infections in children, as well as worsening symptoms of asthma.
The lungs are the major organs of the respiratory system and are responsible for performing gas exchange. The lungs are paired and separated into lobes; The left lung consists of two lobes, whereas the right lung consists of three lobes. Blood circulation is very important, as blood is required to transport oxygen from the lungs to other tissues throughout the body. The function of the pulmonary circulation is to aid in gas exchange. The pulmonary artery provides deoxygenated blood to the capillaries that form respiratory membranes with the alveoli, and the pulmonary veins return newly oxygenated blood to the heart for further transport throughout the body.
The lungs are innervated by the parasympathetic and sympathetic nervous systems, which coordinate the bronchodilation and bronchoconstriction of the airways.
The lungs are enclosed by the pleura, a membrane that is composed of visceral and parietal pleural layers. The space between these two layers is called the pleural cavity. The mesothelial cells of the pleural membrane create pleural fluid, which serves as both a lubricant to reduce friction during breathing and as an adhesive to adhere the lungs to the thoracic wall to facilitate movement of the lungs during ventilation.
Answer the question s below to see how well you understand the topics covered in the previous section. Skip to main content. Module 6: The Respiratory System. Search for:. The Lungs Learning Objectives By the end of this section, you will be able to: Describe the overall function of the lung Summarize the blood flow pattern associated with the lungs Outline the anatomy of the blood supply to the lungs Describe the pleura of the lungs and their function.
Figure 1. Gross Anatomy of the Lungs. Bronchioles control the exchange of gases with the alveoli, which are tiny air sacs in the lungs. Each lobe of the lung has the same physiologic function, bringing oxygen into the bloodstream and removing carbon dioxide. Sections of a lobe, or even entire lobes can be removed as a treatment for conditions such as lung cancer, tuberculosis, and emphysema.
The lumbar vertebrae are the largest movable bones of the backbone. Their large size and bone strength is necessary because these vertebrae support…. Trachea The trachea, also called the windpipe, is part of the passageway that supplies air to the lungs.
Any prolonged blockage, even for a few…. Your legs are two of your most important body parts. They allow you to move and provide support for your upper body.
The ductus deferens, or the vas deferens, is a male anatomical part; there are two of these ducts and their purpose is to carry ejaculatory sperm out…. Humans are sexual, meaning that both a male and a female are needed to reproduce. The lungs are separated by the mediastinum. This area contains the heart , trachea , esophagus , and many lymph nodes. The lungs are covered by a protective membrane known as the pleura and are separated from the abdominal cavity by the muscular diaphragm.
With each inhalation , air is pulled through the windpipe trachea and the branching passageways of the lungs the bronchi , filling thousands of tiny air sacs alveoli at the ends of the bronchi.
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