Founded in 1857, the Science Museum is another renowned museum located in London. Holding a collection of over 300,000 items, the Science Museum is the fifth most visited museum in the United Kingdom with more than 3.4 million visitors annually. 18 MusÃ©e dÂ´Orsay, Paris, France (3.5 million visitors annually)
From the nose, the air passes through the pharynx (the cavity behind the nose and mouth) and the larynx (the voice box). The air then enters the trachea. The trachea carries the air toward the lungs. Before reaching the lungs, the trachea splits into two tubes called the primary bronchi. Each tube enters one lung. Within the lungs, the primary bronchi divide into smaller and smaller tubes, finally branching into extremely tiny tubes called bronchioles.
Words to Know. Alveoli: Tiny air-filled sacs in the lungs where the exchange of oxygen and carbon dioxide occurs between the lungs and the bloodstream. Bronchi: Two main branches of the trachea leading into the lungs.Bronchial tree: Branching, air-conducting subdivisions of the bronchi in the lungs.he exchange of these gases occurs across cell membranes both in the lungs (external respiration) and in the body tissues (internal respiration). Breathing, or pulmonary ventilation, describes the process of inhaling and exhaling air. The human respiratory system consists of the respiratory tract and the lungs.