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Respiratory System Living cells need energy for maintenance, growth, defense, and replication Aerobic respiration Body requires O2 and produces CO2 Our bodies can achieve this by our respiratory exchange surfaces inside the lungs Functions of the Respiratory System 1. moves air to and from the gas- exchange surfaces 2. provides defense against pathogenic invasion 3. permits vocal communication 4. helps control body fluid pH Respiratory Tract Conducting portion and Respiratory portion Conducting airways carry air to and from the exchange surfaces on the lungs these airways filter, warm and humidify the air This protects the alveoli from debris, pathogens and environmental extremes Respiratory Portion includes the smallest and most delicate bronchioles and alveoli that are the site for gas exchange The Nose Air enters the respiratory system via the external nares (nostrils) Coarse hairs guard the nasal cavity from large airborne particles such as sand, dust and insects The Pharynx Chamber shared by the digestive and respiratory systems Extends between the internal nares and the entrance to the larynx and esophagus Hyoid bone is a bone in the neck, that sits on top of the larynx It is the only bone in the human skeleton not articulated to any other bone. It is supported by the muscles of the neck and in turn supports the root of the tongue. The Larynx Incoming air leaves the pharynx, passes through the glottis, which is surrounded and protected by the larynx Prevents food from going down the trachea Filters air, voice box Vocal cords vibrate when air passes through the glottis generating sound waves At puberty, the larynx of a male enlarges more than that of a female. Their vocal cords are thick and longer with lower tones compared to a female. The Trachea “windpipe” Tough, flexible tube ~ 11 cm long and 2.5 cm in diameter The cartilage bands of the trachea support it and keep it from collapsing (~20 of them) C-shape of the cartilages face towards the esophagus and do not continue around the trachea Tracheal Blockage Foreign objects can become lodged in larynx or trachea Coughing can expel the object if the airway isn’t completely blocked. If a person cannot breathe or speak, immediate action must be taken Heimlich Maneuver or abdominal thrust This elevates the diaphragm forcefully and can generate enough pressure to remove the object. Thyroid Gland Regulates metabolism by secreting Thyroxine Maintains hormone levels common thyroid problems involve abnormal production of thyroid hormones. Hyperthyroidism- due to an overproduction of thyroid hormones Hypothyroidism- due to an underproduction of thyroid hormones. Bronchi Left Bronchus- takes air to the left lung Right Bronchus- takes air to the right lung C-Shaped rings that resemble the tracheas Bronchial Tree Think of a tree having a trunk (trachea), two large branches (L. Bronchi & R. Bronchi) Each of the large branches give rise to secondary bronchi that enter the lobes of that lung. The bronchi divide into 9-10 smaller tertiary and the bronchi become smaller and smaller. When the passageways diameter is <1 mm, the narrow passage is a bronchiole Bronchioles Control the amount of resistance to air flow Control the distribution of air in the lungs Sympathetic activation leads to a relaxation of smooth muscles in the walls causing dilation of the respiratory passageways Constriction can block the passageways Ex. Asthma or allergic reactionsinflammation of the bronchioles Alveolar Ducts and Alveoli Bronchioles open into chambers called alveolar ducts The passageways end at the alveolar sacs Alveolar sacs- supply air to alveoli Alveoli- pockets at the end of the respiratory tree Gas exchange with the blood occurs here across the respiratory membrane Gas exchange by diffusion in the lungs The alveoli have a capillary network CO2 leaves the veins and Oxygen enters the alveoli Pneumonia Infection of the lobules of the lung causing inflammation Respiratory function deteriorates Swelling and constricting of the respiratory bronchioles More likely when respiratory defenses are compromised by other factors For ex. Smoking, AIDS The Lungs Area of gas exchange Left and Right Lobes Paired organs of respiration Left- area of gas exchange on L. side Anterior Lobe of Right Lung Median Lobe of Right Lung Posterior Lobe of Right Lung Postcaval Lobe of Right Lung Lungs Most of the actual volume of each lung consists of air-filled passageways and alveoli The lung is light and spongy Elastic fibers give the lungs the ability to tolerate large changes in volume Lung Capacity The total volume of the lungs can be divided into volumes and capacities Expiration reserve vol.- amt. of air that could be voluntarily expelled Inspiratory reserve volume- amt. of air that can be taken in Vital capacity- sum of the inspiratory reserve vol. + expiratory reserve vol. + the tidal vol. = vital capacity Lung Capacity Cont. Residual Volume- air that remains after exhausting the expiratory reserve vol. Minimal Volume- when the lungs collapse and the amt. of air in the respiratory system is reduced to the minimal vol. Pleural Cavities The thoracic cavity has a broad cone shape The walls are the rib cage and its floor is the muscular diaphragm Diaphragm separates the thoracic cavity from the abdominal cavity Each lung occupies a single pleural cavity, lined by a pleura membrane Pleural Cavity Respiration Process 1. Pulmonary ventilation or breathing Movement of air in and out of lungs 2. Gas diffusions across respiratory membrane 3. Storage and transport of oxygen and carbon dioxide 4. Exchange of oxygen and carbon dioxide between the blood and intestinal fluids Tuberculosis TB results from a bacterial infection of the lungs Bacteria colonize in the respiratory passageways or alveoli Symptoms vary- usually coughing and chest pain, fever, night sweats, fatigue, wt. loss Major health problem throughout the world Transmitted through casual contact Basically anyone alive and breathing is at risk ~ 2 billion are infected at this time and 8 mill. Cases are diagnosed each year Bacteria have colonized in the respiratory passageways or alveoli Can target almost any part of your body Pulmonary Ventilation Physical movement of air into and out of the respiratory tract A single breath or respiratory cycle consists of an inhalation (inspiration) and an exhalation (expiration) In other words, breathing in and out one time is a respiratory cycle Emphysema Chronic, progressive condition Shortness of breath and inability to tolerate physical exertion Destruction of the alveolar surfaces and inadequate surface area for oxygen and carbon dioxide exchange Linked to inhalation of air containing fine matter or toxic vapors Ex) cigarette smoke Gas Pickup and Delivery Oxygen is retained by hemoglobin If a tissue has a low oxygen content, oxygen will be released by hemoglobin Carbon Dioxide all transports are reverseable after entering the bloodstream can CO2 may be: 1. dissolved in the plasma 2. bound to the hemoglobin in RBC 3. converted to a molecule of carbonic acid Carbonic acid breaks down into a hydrogen ion and a bicarbonate ion Most hydrogen ions get bound up by hemoglobin molecules Bicarbonate ions diffuse in to the surrounding plasma Here they associate with sodium ions to form sodium bicarbonate (NaHCO3) Carbon Monoxide Poisoning Each year entire families can be killed by leaky furnaces or space heaters Found in the exhaust of automobiles, oil lamps, space heaters Carbon monoxide competes with oxygen for the binding sites on heme units and usually wins because it has a much stronger affinity for hemoglobin Anemia a deficiency of red blood cells or the hemoglobin molecules within them Oxygen has trouble getting where to it needs to go because hemoglobin is not accessible Therefore, the blood struggles to bring oxygen molecules to tissues for energy in the body This can be very serious because the human body depends on oxygen to survive. Ex.) holding your breath under water Weakness, fatigue SIDS Sudden Infant Death Syndrome “crib death” Kills ~ 10,000 infants each year in the United States alone Usually in infants 2-4 months old and usually between midnight and 9 am in the late fall and winter months Eyewitness accounts- infant suddenly stops breathing, turns blue and relaxes Causes-many ideas- genetic, respiratory infections, sleeping position, environment Lung Cancer Originates in the bronchial passageways or alveoli 85-90% of all lung cancers are the direct result of cigarette smoking Symptoms usually don’t appear until the point when the tumor masses are restricting airflow. Common symptoms- cough, wheeze, chest pain, shortness of breath, wt. loss Treatments vary- surgery, radiation or chemotherapy may be involved Lung Cancer Incidence of lung cancer for Nonsmokers- is 3.4 per 100,000 Smokers (half a pack and a pack a day) 59.3 per 100,000 Smokers (one to two packs a day) 217.3 per 100,000 This isn’t surprising with all the toxic chemicals contained in the smoke