<P> Humans have two lungs , a right lung and a left lung . They are situated within the thoracic cavity of the chest . The right lung is bigger than the left , which shares space in the chest with the heart . The lungs together weigh approximately 1.3 kilograms ( 2.9 lb ) , and the right is heavier . The lungs are part of the lower respiratory tract that begins at the trachea and branches into the bronchi and bronchioles , and which receive air breathed in via the conducting zone . The conducting zone ends at the terminal bronchioles . These divide into the respiratory bronchioles of the respiratory zone which divide into alveolar ducts that give rise to the microscopic alveoli , where gas exchange takes place . Together , the lungs contain approximately 2,400 kilometres ( 1,500 mi ) of airways and 300 to 500 million alveoli . Each lung is enclosed within a pleural sac which allows the inner and outer walls to slide over each other whilst breathing takes place , without much friction . This sac also divides each lung into sections called lobes . The right lung has three lobes and the left has two . The lobes are further divided into bronchopulmonary segments and lobules . The lungs have a unique blood supply , receiving deoxygenated blood from the heart in the pulmonary circulation for the purposes of receiving oxygen and releasing carbon dioxide , and a separate supply of oxygenated blood to the tissue of the lungs , in the bronchial circulation . </P>
<P> Humans have two lungs , a right lung and a left lung . They are situated within the thoracic cavity of the chest . The right lung is bigger than the left , which shares space in the chest with the heart . The lungs together weigh approximately 1.3 kilograms ( 2.9 lb ) , and the right is heavier . The lungs are part of the lower respiratory tract that begins at the trachea and branches into the bronchi and bronchioles , and which receive air breathed in via the conducting zone . The conducting zone ends at the terminal bronchioles . These divide into the respiratory bronchioles of the respiratory zone which divide into alveolar ducts that give rise to the microscopic alveoli , where gas exchange takes place . Together , the lungs contain approximately 2,400 kilometres ( 1,500 mi ) of airways and 300 to 500 million alveoli . Each lung is enclosed within a pleural sac which allows the inner and outer walls to slide over each other whilst breathing takes place , without much friction . This sac also divides each lung into sections called lobes . The right lung has three lobes and the left has two . The lobes are further divided into bronchopulmonary segments and lobules . The lungs have a unique blood supply , receiving deoxygenated blood from the heart in the pulmonary circulation for the purposes of receiving oxygen and releasing carbon dioxide , and a separate supply of oxygenated blood to the tissue of the lungs , in the bronchial circulation . </P>
where is the lung located in human body
where is the lung located in human body
within the thoracic cavity of the chest
within the thoracic cavity of the chest