Where is lungs situated

The outer layer of the lungs are the pleura, a type of mesothelium membrane tissue that surrounds the lung and attaches it to the thoracic cavity.

The pleura contain two layers, the outer parietal pleura attached to the thoracic cavity , and the inner visceral pleura covers the lungs. The pleural cavity is the fluid-filled space between the parietal and visceral pleura, and provides room for the lung to expand during inhalation.

The fluid inside the pleural cavity protects against irritation during inhalation as well. Interior of the thoracic cavity : This is a transverse view of the thoracic cavity, showing the pleural cavity and the major structures around the lungs.

The interior of the lung contains the alveoli, where gas exchange occurs. The alveoli branch off from the bronchioles and bronchi that connect to the trachea and allow air to pass into the lungs. The lungs are divided into lobes by fissures on the outer surface of the lung, and divide further into segments and finally into hexagonal lobules, the smallest divisions of the lungs.

Breathing is largely driven by the muscular diaphragm at the bottom of the thorax. Contraction of the diaphragm pulls the bottom of the cavity in which the lung is enclosed downward, increasing volume and thus decreasing pressure, causing air to flow into the airways and into the lungs.

During normal breathing, expiration is passive— no muscles are contracted—and the diaphragm relaxes from its contracted state.

The elastic recoil of the lungs automatically pulls the lungs inward during exhalation. The rib cage itself is also able to expand and contract to some degree during breathing, through the action of other respiratory and accessory respiratory muscles.

As a result, air is transported into or expelled out of the lungs. The major function of the lungs is gas exchange, which occurs in the alveoli of the lung. Oxygen dissolves through the extracellular matrix of the alveoli that lets the gas diffuse into the capillaries based on the relative partial pressures of the gasses gasses flow from areas of high pressure to low pressure.

Oxygen passively diffuses into the deoxygenated blood of the capillaries while carbon dioxide passively diffuses out of the deoxygenated blood and into the airways. Only a relatively small proportion of alveoli in the lungs are perfused with blood and actually take part in gas exchange. Too low perfusion and a higher ratio indicates alveolar dead space, while too low ventilation and a lower ratio indicates a shunt, which is a lack of air supply relative to perfusion.

The lungs are located on either side of the heart and are separated by fissures into lobes, three in the right and two lobes in the left. The lungs are located in two chambers of the thoracic cavity on either side of the heart.

Though similar in appearance, the two lungs are not identical, nor wholly symmetrical. Fissures are double folds of pleura that divide the lung into lobes. There are three lobes in the right lung and two in the left lung. The lobes are further divided into segments and then into lobules, which are hexagonal divisions of the lungs that are the smallest visible subdivision. The lobes are further divided into segments and then into lobules, hexagonal divisions of the lungs that are the smallest subdivision visible to the naked eye.

The lobes of the lungs : The right lung has three lobes and the left lung has two. The right lung is five centimeters shorter than the left lung to accommodate the diaphragm, which rises higher on the right side over the liver; it is also broader. The volume, the total capacity, and the weight of the right lung is greater than that of the left. The right lung is divided into three lobes. The upper lobe is the largest lobe of the right lung.

It extends from the apex of the lung down to the horizontal and oblique fissures. It bears apical, anterior, and posterior bronchopulmonary segments. The middle lobe is the smallest lobe of the right lung, located between the horizontal and oblique fissures. It bears medial and lateral bronchopulmonary segments. The lower lobe is the bottom lobe of the right lung.

It lies beneath the oblique fissure. It bears medial, lateral, superior, anterior, and posterior bronchopulmonary segments. The Left Lung : This has a concave depression that accommodates the shape of the heart, called the cardiac notch. The human left lung is smaller and narrower that the right lung, and is divided into two lobes, an upper and a lower, by the oblique fissure.

The left lung has only two formal lobes because of the space taken up in the left side of the chest cavity by the heart, though it does have the lingula, which is similar to a lobe. The left lung has a depression on the medial side of its surface called the cardiac notch, a concave impression molded to accommodate the shape of the heart.

The upper lobe of the left lung contains anterior and apicoposterior bronchopulmonary segments. The lungs also help the body to get rid of CO 2 gas when we breathe out. There are a number of other jobs carried out by the lungs that include:. Breathing in is called inhalation. The most important muscle of inhalation is the diaphragm. Found beneath the lungs, the diaphragm is a dome-shaped muscle.

When this muscle gets tighter contracts , it flattens and the lungs increase in size. This sucks air down into your lungs. Some of the oxygen in the air can then be transferred into your bloodstream. Some of the carbon dioxide in your blood is transferred into the air that is in your lungs. This controls the levels of oxygen and carbon dioxide in your bloodstream. See also the separate leaflet called The Heart and Blood Vessels for more information on how blood is pumped to the lungs and to the rest of your body.

Breathing out exhalation is the opposite of inhalation. The diaphragm and other chest muscles relax. This makes the lungs decrease in size so that air is pushed back out of your lungs and out through your mouth or nose. The basic rhythm of breathing is controlled by the brain. Part of the brain called the brainstem has a special area dedicated to maintaining your breathing pattern. Nerve impulses from the brainstem control the contractions of your diaphragm and the other muscles of breathing.

This is all done without thinking. However, other parts of the brain can temporarily overrule the brainstem. This is how we are able consciously to hold our breath or change our pattern of breathing.

While the brain controls the basic rhythm of breathing, it also receives information from sensors in the body. These sensors are nerve cells and provide information that influences the rate and depth of breathing. The main sensors monitor levels of CO 2 in the blood. Once the blood has plenty of oxygen and no carbon dioxide, it is returned to the heart and pumped to the rest of the body. Search temple health.

How the Lungs Work. Airways The body uses several channels to bring oxygen-rich air into the lungs and release carbon dioxide a waste gas out of the lungs. When you breathe out, air leaves the body through your airways. Lungs The lungs are located on either side of the breastbone in the chest cavity and are divided into five main sections lobes. Muscles Many muscles are required to help the lungs expand and tighten during breathing: The diaphragm: Located below the lungs, the diaphragm is the main muscle needed to breathe.

It separates the chest and abdominal cavities and contracts to help inflate the lungs. Intercostal muscles: Located between the ribs, these muscles give the lungs room to breathe by expanding and contracting the chest cavity. Abdominal muscles: These muscles give the lungs room to breathe by compressing the organs in the abdominal cavity.