Respiratory System: pp. 885-890

Respiratory System:pp. 885-890 • Pre-Movie: http://kidshealth.org/kid/closet/movies/how_the_body_works_interim.html • Major structures: • Lungs • Nose • Mouth • Trachea

Respiratory System Functions • Moves air into and out of lungs • Controls gas exchange between blood and lungs

Key terms • Pharynx – a muscular tube in the upper throat which serves as a passageway for air and food • Larynx – a passageway for air, or the voice box, that is located in the neck • the flap of tissue that covers the opening to the larynx when you swallow food or liquids is called the epiglottis • Trachea – a long, straight tube in the chest cavity; also referred to as the windpipe

Key terms • Bronchi – one of the two smaller tubes that the trachea divides into; this one leads to the lungs • Bronchi divide into smaller tubes called bronchioles and bronchioles end in clusters of air sacs called alveoli • Alveoli – Clusters of air sacs where gases are actually exchanged • Lungs – among the largest organs in the body, the lungs are suspended in the chest cavity, bound on the sides by the ribs and on the bottom by the diaphram • Diaphragm – a powerful muscle spanning the ribcage under the lungs that aids in respiration

Breathing • The process by which air is drawn into and pushed out of the lungs • Inhalation – the process of drawing air into the lungs (rib muscles and diaphragm contract) • Exhalation – the process of breathing out (rib cage and diaphragm muscles relax)

http://kvhs.nbed.nb.ca/gallant/biology/negative_pressure_breathing.htmlhttp://kvhs.nbed.nb.ca/gallant/biology/negative_pressure_breathing.html

Summary of the path of oxygen and carbon dioxide through the body • Oxygen from the outside air reaches the lungs. • The oxygen diffuses from the alveoli to the pulmonary capillaries. At the high oxygen levels that occur in the blood within the lungs, most hemoglobin molecules carry a full load of oxygen. • The oxygen-rich blood then travels to the heart. The heart pumps the blood to the tissues of the body. • Oxygen diffuses into the cells for use during aerobic respiration. In the tissues, oxygen levels are lower. This causes the hemoglobin to release its oxygen. • In tissues, the presence of carbon dioxide produced by cellular respiration makes the blood more acidic and causes the hemoglobin molecules to assume a different shape, one that gives up oxygen more easily. The carbon dioxide diffuses from the cells to the blood. • Most of the carbon dioxide travels to the heart as bicarbonate (HCO3- )ions. • The heart pumps the blood to the lungs. In the lungs, carbon dioxide is released in its gaseous form to the alveoli. • The carbon dioxide is expelled.

What is asthma? • A chronic condition in which the bronchioles of the lungs become inflamed, because of their sensitivity to certain stimuli in the air. • The bronchial walls tighten and extra mucus is produced, causing the airways to narrow • In severe asthma attacks, the alveoli may swell enough to rupture. • Although asthma can be deadly if left untreated, prescribed medical inhalant medicines may help to stop an asthma attack by expanding the bronchioles.

http://trickledown.files.wordpress.com/2009/04/asthma.jpg

What is emphysema? • A chronic pulmonary disease resulting from a chemical imbalance that destroys elastic fibers in the lungs (normally these fibers allow the lungs to expand and contract) • Emphysema begins with the destruction of alveoli • This damage is irreversible and results in constant fatigue and breathlessness • Severely affected individuals must breathe from tanks of oxygen in order to live • Smoking is the cause of up to 90% of emphysema patients

Lung cancer: smoking is the major cause

Respiratory System Activities • http://msjensen.cehd.umn.edu/WEBANATOMY/timed/36.htm • http://www.vtaide.com/png/respiratoryF.htm • http://www.getbodysmart.com/ap/respiratorysystem/menu/menu.html • http://health.howstuffworks.com/adam-200020.htm • http://msjensen.cehd.umn.edu/webanatomy/game/Respiratory.htm

Respiratory System: pp. 885-890