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SNC2P: Biology NAME: MS. WONG (ANSWER KEY) Date: _______________ The task of respiratory system is to exchange oxygen and carbon dioxide between the body and its surroundings. The main parts of the respiratory system are nose, mouth, trachea, bronchi, bronchioles, lungs, rib cage + muscle, and diaphragm. Gas exchange takes place in the air sacs (alveoli) in the lungs. These sacs are surrounded by capillaries. Respiration 3D Medical Animation http://www.youtube.com/watch?v=HiT621PrrO0 SNC2P: Biology Branching out → to increase surface area (such as tree roots) where oxygen can be absorbed; much more than if the lungs were one hollow chamber. Tiny thin-walled blood vessels called capillaries surround each alveolus. Oxygen passes through the walls of the alveoli and into the capillaries and is carried throughout the body. Oxygen is used to burn food in the form of simple sugars, to release energy. This is called cellular respiration. The waste products of this process are carbon dioxide and water, which diffuse from the cells through the capillary walls and into the blood. They are carried back to the alveoli and exhaled from the lungs. SNC2P: Biology Gas Exchange Oxygen Transport The air we breathe into our lungs has a higher concentration of oxygen than the blood in the capillaries around the air sacs (alveoli). The oxygen diffuses through the air sacs (alveoli) and the capillaries into the blood. Oxygen moves from the lungs into the blood, and the blood transport the oxygen to other parts of the body. Removing Carbon Dioxide Carbon dioxide is a waste gas produced by the body as the body uses energy to move, grow and repair itself. The blood carries carbon dioxide to the lungs. Carbon dioxide diffuses from the blood into the air sacs (alveoli). Carbon dioxide is then released through the mouth or nose when we breathe out. Respiration http://www.youtube.com/watch?v=bwXvqSqAgKc SNC2P: Biology Breathing Breathing air in and out is simply a mechanical process related to pressure changes caused by the increase and decrease of the chest cavity size. Breathing http://www.youtube.com/watch?v=gYSIWceGMxY&NR=1 http://www.youtube.com/watch?v=Mf8xTqfspp4&feature=related SNC2P: Biology When inhaling, diaphragm contracts and drops down. ribs expand outward, making the chest cavity larger. This causes the pressure in the cavity to decrease, resulting in air being drawn into the lungs which causes them to expand. When exhaling, the diaphragm relaxes and moves up, and the ribs settle down. The cavity is made smaller, causing the pressure to increase and results in the lungs contracting and forcing carbon dioxide-laden air out of the lungs. MUCUS & CILIA The nose and air passages produce a slippery liquid called mucus, which helps to warm and moisten the air and allows it to travel the airways more easily. Mucus also helps to trap dirt and dust particles and some bacteria. Tiny hairs called cilia, located on the inner walls of the air passages, slowly move the mucus up toward the throat and nose, carrying with it any foreign particles. If particles irritate the nose, a sneeze may occur. If the particles are located deeper in the air passages a hearty cough will move them out. Much more mucus is produced when the body is fighting a cold. There are special epithelial cells that line the larger bronchi. Each cell has about 250 cilia growing from it. SNC2P: Biology Goblet cells located between the epithelial cells produce almost half a cup of mucus a day. As the cilia beat (about 1,0001,500 times per minute), they move the mucus containing trapped foreign matter about 1020 mm in a minute or about a mile in a week. When the mucus gets into the upper airways, it can be coughed out. A cough is triggered when mucus or foreign matter irritates nerve endings in the larynx, trachea, or larger bronchi. When irritating particles stimulate the nerve endings at the back of the nasal cavity, a sneeze results. The impulse to sneeze can be turned off briefly by pressing hard with a finger under the nose. SNC2P: Biology Respiratory Diseases Chronic obstructive pulmonary diseases (COPD): Diseases that reduce the flow of air into and out of the lungs; make it difficult to breathe Three main types: asthma, emphysema and chronic bronchitis affect the ability of the respiratory system to exchange gases. Asthma: airway swelling and mucus production Emphysema: tiny air sacs in the lungs collapse and the wall between them are destroyed; less oxygen can be picked up by the blood. Chronic bronchitis: tissues lining the airway become swollen. Passageway for air is narrowed, causing coughing and breathlessness. Causes of respiratory disease: 1. Smoking and exposure to second-hand smoke 2. Exposure to pollution 3. Exposed to chlorine in swimming pools Asthma http://www.youtube.com/watch?v=S04dci7NTPk&feature=related COPD http://www.youtube.com/watch?v=u775bGjJazM SNC2P: Biology What is Asthma? Asthma is a chronic (long-term) disease that makes it hard to breathe. If you have asthma, your airways (breathing passages) are extra sensitive. When you are around certain things, your extra-sensitive airways can: o Become red and swollen - your airways get inflamed inside. They fill up with mucus. The swelling and mucus make your airways narrower, so it's harder for the air to pass through. o Become "twitchy" and go into spasm - the muscles around your airways squeeze together and tighten. This makes your airways narrower, leaving less room for the air to pass through. o The more red and swollen your airways are, the more twitchy they become. Normal airways Airways of a person without asthma Airways of a person with asthma - redness and swelling (inflammation) Airways of a person with asthma - tightened muscles (bronchospasm) In people without asthma, the muscles around the airways are relaxed, allowing the airways to stay open. There is no swelling or mucus inside the airways. In people with asthma, the inside of the airways can get red, swollen, and filled with mucus. In people with asthma, the muscles around the airways can spasm and squeeze tighter. This leaves less room for air to pass through SNC2P: Biology SNC2P: Biology Emphysema SNC2P: Biology The bronchi and bronchioles are inflamed and continually swollen and clogged. This causes the alveoli to swell. These fragile air sacs burst and merge together. This damage to the alveoli makes it more difficult for the transfer of oxygen and carbon dioxide to take place. People with emphysema have difficulty breathing. It is usually caused by cigarette smoking, or a severe form of bronchitis called chronic obstructive bronchitis. Very often, a combination of these factors produces emphysema. Who Gets Emphysema? Both emphysema and COPD are very rare in young people, but the incidence * steadily increases as people grow older, particularly during or after middle age. This is believed to be due in large part to the cumulative effect of smoking on the lungs. One person cannot catch it from another. Emphysema is more common in men than it is in women, probably because more men smoke cigarettes than women. However, it is believed that this difference will become smaller because more teenage girls and young women are smoking cigarettes today than years ago. In the United States, more than 2 million people have emphysema, making it a common disorder. More than 6 million people suffer from COPD. About 6 or 7 people per 100,000 die from emphysema each year, and COPD is the fourth most common cause of death in the United States. The incidence of emphysema is even higher in European countries. SNC2P: Biology Effects of Smoking and Other Causes The great majority of emphysema cases are associated with cigarette smoking. It has been found that people who are heavy smokers of cigarettes are 10 to 15 times more likely to develop emphysema than are nonsmokers. Environmental air pollution also may make a person more likely to develop chronic bronchitis and emphysema. What Are the Symptoms of Emphysema? The main symptom of emphysema is shortness of breath. The person must breathe harder to force carbon dioxide out of the lungs and draw in oxygen. A common outward sign of emphysema is a barrel-shaped chest caused by overinflation of the lungs. A slice of human lung tissue with pulmonary emphysema. The affected lung area is the top portion, with severe lung damage in the blackened area. Normal lung tissue is shown on the bottom for comparison. Dr. E Walker/Science Photo Library, Photo Researchers, Inc. SNC2P: Biology Chronic Bronchitis SNC2P: Biology If you have chronic bronchitis: the cells lining the inside of the bronchi are continuously red and swollen the airways in your lungs have become narrow and partly clogged with mucus With chronic bronchitis, the mucus cannot be cleared. Instead of helping to clean the lungs, the mucus blocks your airways. The mucus is thicker and more difficult to cough up. This means it's easier for bacteria to settle in your lower airways and become infected. Chronic bronchitis is usually caused by cigarette smoke. It can also be caused by other things. The main symptoms of chronic bronchitis are: a persistent cough (cough that won't go away) extra mucus (phlegm) in the lungs SNC2P: Biology SNC2P: Biology SNC2P: Biology SNC2P: Biology Number 1 2 3 4 5 6 7 8 9 10 11 12 13 Functions nasal cavity mouth epiglottis trachea bronchi ribs muscles lungs diaphragm esophagus bronchioles capillaries alveoli warm, moisten and filter air warm, moisten and filter air ANSWERS Number 1 2 3 4 5 6 7 8 9 10 11 12 13 Functions nasal cavity mouth epiglottis trachea bronchi ribs muscles lungs diaphragm esophagus bronchioles capillaries alveoli warm, moisten and filter air warm, moisten and filter air prevent food from entering trachea carries air to the bronchi carry air to the lungs helping with the process of breathing helping with the process of breathing gas exchange happens here helping with the process of breathing carries air to the alveoli gas exchange (part of circulatory system) gas exchange SNC2P: Biology A flow chart showing the path oxygen takes when it enters respiratory system mouth or nose trachea bronchi bronchioles alveoli capillaries A flow chart showing the path carbon dioxide takes when it leaves the circulatory system into the respiratory system SNC2P: Biology The Respiratory System SNC2P: Biology The Respiratory System SNC2P: Biology SNC2P: Biology