1. Respiratory System

3.  One of the largest organ systems in the body  1,500 miles of airways and almost 1,000 miles of capillaries in the lungs  Surface area of lungs is 80x greater than surface area of skin  Exchange of oxygen and carbon dioxide through respiration  External, internal and cellular respiration  Production of sound  Larynx contains vocal cords

4.  External respiration/breathing  Exchange of oxygen and carbon dioxide between the lungs, the body, and the outside environment  Consists of inspiration (inhalation) and expiration (exhalation)  Internal respiration  Exchange of carbon dioxide and oxygen between the cells and the lymph surrounding them  Cellular respiration/oxidation  Use of oxygen to release energy stored in nutrient molecules such as glucose  This chemical reaction occurs within the cells

6.  Nasal cavity  Air enters nostrils or anterior nares, then the nasal cavity (separated by the nasal septum) lined with mucous membrane  Three nasal conchae bones (turbinates) that increase the surface area of the nasal cavity  Air moistened by mucous and warmed by blood vessels  Cilia entrap particles and filter air  Pharynx  Commonly known as throat; passageway for food and air  5 inches long and subdivided into nasopharynx (connected to eustachian tubes), oropharynx, and laryngopharynx  Epiglottis is flap of cartilage lying behind the tongue and in front of entrance to larynx

7.  Larynx  Aka voice box, a triangular chamber found below the pharynx  Composed of 9 fibrocartilaginous plates, largest known as the Adam’s apple  Characteristic vocal cords with space known as glottis  Trachea  Aka windpipe, tubelike passageway extending from larynx and continues to form the two bronchi  Composed of 15 to 20 C-shaped virtually non-collapsible rings of hyaline cartilage  Bronchi and Bronchioles  Lower end of trachea separates into right and left bronchus (right bronchus is shorter, wider, and more vertical in position)  As they enter the lung, they subdivide into smaller bronchioles (Y shaped in form)

8.  Alveoli  Alveolar sacs consist of many alveoli  Adult lung has about 500 million alveoli (3x the amount necessary to sustain life)  Inner surfaces covered with surfactant which helps stabilize the alveoli  Through the moist walls of alveoli and capillaries is where rapid exchange of carbon dioxide and oxygen occurs  Lungs  Separated by the mediastinum  The apex is the top of each lung; broad lower part is the base which rests over the diaphragm  Right lung has three lobes, left lung has two lobes

9.  Pleura  A thin, moist, slippery membrane of tough endothelial cells that covers the lungs  Each lung encased in double-walled sac (visceral and parietal pleura)  Pleural fluid is located between the two membranes and prevents friction during each breath  Mediastinum  AKA the interpleural space, located between the lungs  Contains the thoracic viscera (thymus gland, heart, aorta, esophagus, trachea, thoracic duct, lymph nodes, and vessels)

15.  Due to changes in pressure that occur within the chest cavity caused by cellular respiration and mechanical breathing movements  Inhalation/inspiration  Diaphragm contracts and pulls downward, causing the thoracic cavity to expand  Exhalation/expiration  Diaphragm relaxes and moves upwards, causing the thoracic cavity to become narrower  Respiratory movements and frequency of respiration  Normal rate in quiet breathing for an adult male is about 14 to 20 breaths per minute (females are 16 to 20 breaths)  Can be increased by muscular activity, increased body temperatures, emotions, and certain pathological disorders  Can be decreased by sleeping and emotions

16.  Neural factors  Two neuronal pathways involved in breathing: phrenic nerves lead to diaphragm and intercostal muscle; the vagus nerve carries impulses to nose, larynx, lungs, skin, and abdominal organs  Chemical factors  Level of carbon dioxide in the blood: as blood circulates through respiratory center, it senses increased carbon dioxide levels in blood and increases respiratory rate  Chemoreceptors found in carotid arteries and aorta: if oxygen levels decline to low levels, impulses are sent which will stimulate the rate and depth of respiration

17.  Spirometer: device that measures the volume and flow of air during inspiration and expiration  Tidal volume: amount of air that moves in and out of lungs with each breath (~500 mL)  Inspiratory reserve volume (IRV): amount of air you can force a person to take in above the tidal volume (~2100-3000 mL)  Expiratory reserve volume (ERV): amount of air you can force a person to exhale above the tidal volume (~1000 mL)

18.  Apnea: temporary stoppage of breathing movements  Dyspnea: difficult, labored, or painful breathing  Eupnea: normal or easy breathing  Hyperpnea: increase in depth and rate of breathing accompanied by abnormal exaggeration of respiratory movements

19.  Orthopnea: difficult or labored breathing when in a horizontal position  Tachypnea: abnormally rapid and shallow rate of breathing  Hyperventilation: condition that can be caused by disease or stress; rapid breathing causing the body to lose carbon dioxide too quickly leading to dizziness and possible fainting

21.  Lung tissue loses elasticity  Rib cage becomes less flexible  Muscle strength decreases  Functioning alveoli decrease

22.  Common cold: hundreds of strains of the virus; runny nose, watery eyes, sneezing, stuffy head, and sore throat  Pharyngitis: bacterial or viral; painful swallowing and extreme dryness of throat  Laryngitis: secondary to other infections; hoarseness or loss of voice  Sinusitis: viral or bacterial; sinus pain and nasal discharge  Bronchitis: viral or bacterial; cough, fever, substernal pain, and rales/raspy sound

23.  Influenza (flu): viral infection; fever, mucous discharge, muscular pain, and extreme exhaustion  Pneumonia: viral or bacterial; chest pain, fever, chills, and dyspnea  Tuberculosis (TB): bacterial infection; cough, low-grade fever, weight loss, night sweats  Pertussis (whooping cough): bacterial infection; severe coughing attacks and dyspnea

24.  Rhinitis: inflammation of nasal mucous membranes causing swelling and increased secretions  Asthma: airways become obstructed due to an inflammatory response to a stimuli  Atelectasis: lungs fail to expand normally due to blockage of air passages  Pneumothorax: buildup of air within the pleural cavity on one side of the chest causing the lung to collapse

25.  Chronic obstructive pulmonary disease (COPD): group of lung diseases that limit air flow as a person exhales due to lung irritants and smoking  Cancer of the lung: most common cause of cancer death in the US  Pulmonary embolism: blood clot travels to the lungs after surgery or bed rest  Sudden infant death syndrome (SIDS): occurs in infants between 2 weeks to 1 year who stop breathing; exact causes unknown