They remove the carbon dioxide and other waste gases that your body's doesn't need. To breathe in inhale , you use the muscles of your rib cage — especially the major muscle, the diaphragm. Your diaphragm tightens and flattens, allowing you to suck air into your lungs. To breathe out exhale , your diaphragm and rib cage muscles relax. This naturally lets the air out of your lungs. To get the oxygen your body needs, you inhale air through your mouth and nose. The mucous membranes in your mouth and nose warm and moisten the air, and trap particles of foreign matter like dirt and dust.
They contract to pull your rib cage both upward and outward when you inhale. As your lungs expand, air is sucked in through your nose or mouth. The air travels down your windpipe and into your lungs.
After passing through your bronchial tubes, the air travels to the alveoli, or air sacs. Gas exchange in your lungs. When you breathe in, air enters your nose or mouth, and passes into your windpipe, also called the trachea.
At the bottom, the windpipe divides into two bronchial tubes, then branches into smaller bronchioles. The brochioles end in tiny air sacs, called alveoli. In the alveoli, the oxygen you inhaled passes into the bloodstream, and carbon dioxide from your body passes out of the bloodstream.
Through the thin walls of the alveoli, oxygen from the air passes into your blood in the surrounding capillaries. At the same time, carbon dioxide moves from your blood into the air sacs. The oxygen in your blood is carried inside your red blood cells by a protein called hemoglobin. The oxygen-rich blood from your lungs is carried to the left side of the heart through the pulmonary veins. The heart pumps the blood to the rest of the body, where oxygen in the red blood cells moves from blood vessels into your cells.
Your cells use oxygen to make energy so your body can work. During this process, your cells also make a waste gas called carbon dioxide. Carbon dioxide needs to be breathed out or it can damage your cells.
Carbon dioxide moves from the cells into the bloodstream, where it travels to the right side of your heart. The blood rich in carbon dioxide is then pumped from the heart through the pulmonary artery to the lungs, where it is breathed out. When you breathe out, or exhale, your diaphragm and rib muscles relax, reducing the space in the chest cavity. As the chest cavity gets smaller, your lungs deflate, similar to releasing of air from a balloon. At the same time, carbon dioxide-rich air flows out of your lungs through the windpipe and then out of your nose or mouth.
Breathing out requires no effort from your body unless you have a lung disease or are doing physical activity. When you are physically active, your abdominal muscles contract and push your diaphragm against your lungs even more than usual. This rapidly pushes air out of your lungs.
Damage, infection, or inflammation in the lungs or airways or both, can lead to the following conditions. Exposure to cigarette smoke, air pollutants, or other substances can damage the airways, causing disease of the airways or making a disease more severe. You can take these steps to help protect your lungs from injury or disease:.
As you age, the lung tissue that helps keep your airways open can lose elasticity, which means they cannot expand or contract as easily as when you were younger. The muscles your body uses for breathing may get smaller or weaker, and your spine can curve more, leaving less space for your lungs to expand.
It can take longer to clear mucus and particles from your airways. It can also become harder to cough. These changes can make it harder to breathe during physical activity as you get older. We are committed to advancing science and translating discoveries into clinical practice to promote the prevention and treatment of heart, lung, blood, and sleep disorders.
Learn about current and future NHLBI efforts to improve health through research and scientific discovery. Learn about the following ways the NHLBI continues to translate current research to prevent and treat lung problems. Learn about some of the pioneering research contributions we have made over the years that have improved clinical care.
In support of our mission , we are committed to advancing lung research in part through the following ways. We lead or sponsor studies on the lungs. See if you or someone you know is eligible to participate in a clinical trials. To learn more about clinical trials at the NIH Clinical Center or to talk to someone about a study that might fit your needs, call the Office of Patient Recruitment Learn more about participating in a clinical trial.
View all trials from ClinicalTrials. After reading our How the Lungs Work Health Topic, you may be interested in additional information found in the following resources. This Symposium will highlight important scientific advances in pulmonary health and disease since the creation of t How the Lungs Work. Also known as Respiratory System. Read more. The pleura Cross-section of lungs to show the pleura. The main image shows the location of the lungs, pleura, and diaphragm.
The inset image shows a closer view of the two layers of the pleura and the pleural space. Read less. The muscles used for breathing The lungs are like sponges; they cannot expand get bigger on their own. The breathing muscles include the: Diaphragm, which is a dome-shaped muscle below your lungs. It separates the chest cavity from the abdominal cavity. The diaphragm is the main muscle used for breathing. The muscles between your ribs, called intercostal muscles, play a role in breathing during physical activity.
Abdominal muscles help you breathe out when you are breathing fast, such as during physical activity. Muscles of the face, mouth, and pharynx. The pharynx is the part of the throat right behind the mouth. These muscles control the lips, tongue, soft palate, and other structures to help with breathing.
Problems with these muscles can narrow the airway, make it more difficult to breathe, and contribute to sleep apnea. Muscles in the neck and collarbone area help you breathe in. Cross-section of lungs to show the diaphragm. The nervous system Your breathing usually does not require any thought, because it is controlled by the autonomic nervous system, also called the involuntary nervous system.
The parasympathetic system slows your breathing rate. It causes your bronchial tubes to narrow and the pulmonary blood vessels to widen.
The sympathetic system increases your breathing rate. It makes your bronchial tubes widen and the pulmonary blood vessels narrow. Sensors in the airways detect lung irritants.
The sensors can trigger sneezing or coughing. In people who have asthma, the sensors may cause the muscles around the airways in the lungs to contract. This makes the airways smaller. Sensors in the brain and near blood vessels detect carbon dioxide and oxygen levels in your blood.
Sensors in your joints and muscles detect the movement of your arms or legs. These sensors may play a role in increasing your breathing rate when you are physically active. Breathing in When you breathe in, or inhale, your diaphragm contracts and moves downward.
Gas exchange. You can take these steps to help protect your lungs from injury or disease: Quit smoking , or not starting if you do not smoke. The two openings of the airway the nasal cavity and the mouth meet at the pharynx pronounced: FAR-inks , or throat, at the back of the nose and mouth. The pharynx is part of the digestive system as well as the respiratory system because it carries both food and air. At the bottom of the pharynx, this pathway divides in two, one for food — the esophagus pronounced: ih-SAH-fuh-gus , which leads to the stomach — and the other for air.
The epiglottis pronounced: eh-pih-GLAH-tus , a small flap of tissue, covers the air-only passage when we swallow, keeping food and liquid from going into the lungs. The larynx, or voice box, is the top part of the air-only pipe. This short tube contains a pair of vocal cords, which vibrate to make sounds. The trachea, or windpipe, is the continuation of the airway below the larynx.
The walls of the trachea pronounced: TRAY-kee-uh are strengthened by stiff rings of cartilage to keep it open. The trachea is also lined with cilia, which sweep fluids and foreign particles out of the airway so that they stay out of the lungs. At its bottom end, the trachea divides into left and right air tubes called bronchi pronounced: BRAHN-kye , which connect to the lungs. Within the lungs, the bronchi branch into smaller bronchi and even smaller tubes called bronchioles pronounced: BRAHN-kee-olz.
Bronchioles end in tiny air sacs called alveoli, where the exchange of oxygen and carbon dioxide actually takes place. Each person has hundreds of millions of alveoli in their lungs. This network of alveoli, bronchioles, and bronchi is known as the bronchial tree.
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