37-3 The Respiratory System Copyright Pearson Prentice Hall

The Human Respiratory System The respiratory system consists of the: Epiglottis Trachea Nose Pharynx Larynx Lungs Bronchus Mouth Diaphragm Bronchioles The respiratory system is responsible for the exchange of oxygen and carbon dioxide. Air moves through the nose, pharynx, larynx, trachea, and lungs. After reaching the lungs, the trachea branches into smaller and smaller tubes called bronchioles, which end in alveoli, or air sacs. Copyright Pearson Prentice Hall

Copyright Pearson Prentice Hall What Is Respiration? What Is Respiration? In biology, respiration means different things. Cellular respiration is the release of energy from the breakdown of food in the presence of oxygen (occurs in which organelle?) At the organism level, respiration is the process of gas exchange—the release of carbon dioxide and the uptake of oxygen that occurs between RBCs and alveoli Breathing is the actual mechanical intake of air MITOCHONDRIA Copyright Pearson Prentice Hall

Copyright Pearson Prentice Hall Breathing BREATHING Lungs are sealed in pleural membranes inside the chest cavity. At the bottom of the cavity is a large, flat muscle known as the diaphragm. Pleural cavities are like big plastic bag around the lungs. During inhalation the rib cage rises and the diaphragm contracts, increasing the size of the chest cavity. Copyright Pearson Prentice Hall

Copyright Pearson Prentice Hall Breathing During inhalation, the diaphragm contracts and the rib cage rises up. This expands the volume of the chest cavity. The chest cavity is sealed, so this creates a partial vacuum inside the cavity. Atmospheric pressure fills the lungs as air rushes into the breathing passages. During inhalation the rib cage rises and the diaphragm contracts, increasing the size of the chest cavity. Copyright Pearson Prentice Hall

Copyright Pearson Prentice Hall Everyone take a deep breath and hold it. That is INHALATION Your rib cage and diaphragm expand. Copyright Pearson Prentice Hall

Copyright Pearson Prentice Hall Breathing Often exhaling is a passive event. When the rib cage lowers and the diaphragm relaxes, pressure in the chest cavity is greater than atmospheric pressure. Air is pushed out of the lungs. Air Exhaled Rib cage lowers During inhalation the rib cage rises and the diaphragm contracts, increasing the size of the chest cavity. Exhalation Copyright Pearson Prentice Hall

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How Breathing Is Controlled Breathing is controlled by the medulla oblongata. The medulla oblongata monitors carbon dioxide in the blood. As carbon dioxide increases, nerve impulses make the diaphragm contract, bringing air into the lungs. The higher the carbon dioxide level, the stronger the impulses. Copyright Pearson Prentice Hall

Copyright Pearson Prentice Hall So what’s a hiccup? A hiccup is a muscle spasm of the diaphragm. Guinness medical record breakers. Longest attack ofhiccups. Charles Osborne (1894-1991) of Anthon, Iowa, the US, started hiccupping in 1922 while attempting to weigh a hog before slaughtering it. He was unable to find a cure, and continued hiccupping until February 1990, a total of 68 years. Copyright Pearson Prentice Hall

The Human Respiratory System RESPIRATION Alveoli are clusters of tiny sacs at the ends of air passages. A network of capillaries surrounds each alveolus. Pulmonary artery Pulmonary vein The respiratory system is responsible for the exchange of oxygen and carbon dioxide. Capillaries Copyright Pearson Prentice Hall

Copyright Pearson Prentice Hall Gas Exchange RESPIRATION Gas exchange takes place in the alveoli. Oxygen diffuses into the blood. Carbon dioxide in the blood diffuses out of the blood to the alveolus. Let’s examine this up close O2 CO2 Gas exchange occurs by diffusion across the membrane of an alveolus and a capillary. Capillary Copyright Pearson Prentice Hall