Respiratory System Vocabulary – For flashcards respiration The act or process of breathing in oxygen from the air and breathing out carbon dioxide and water from the lungs alveoli The balloon-like air sacs at the end of the bronchiolus in the lungs bronchi Two cartilage-ringed tubes that go from the trachea directly to each lung bronchiole The tiny, thin walled branches of the bronchi diaphragm A dome shaped muscle that lies just below the lungs and is the main muscle involved in breathing pleura A layer of tissue surrounding each lung and lining the chest cavity residual Remaining effective for some time; such as residual breath in the lungs trachea The windpipe that branches off into two bronchi; the pathway that air moves from the throat into the chest larynx The part of the throat that holds the vocal cords pharynx The throat arteries Thick walled, elastic blood vessels that carry blood away from the heart to the rest of the body veins Large, thin walled blood vessels that carry blood to the heart from different parts of the body capillaries Tubes that connect the arteries and veins – they are the smallest blood vessels with thin walls to allow oxygen and nutrients to pass through carbon dioxide A gas made up of carbon and oxygen that is produced during respiration and is exhaled while breathing oxygen A gas used in our bodies, with food, to release the energy we need to stay alive pulmonary Relating to the lungs cilia Very small hairs that line parts of the respiratory system and filter air and trap dust particles mucus Sticky phlegm or liquid in parts of the respiratory system that catches and holds dust and germs .