Respiratory System Respiration processes Pulmonary ventilation air in out gas exchanged in lungs External respiration gas exchanged between blood and alveoli in lungs Transport of respiratory gases transport of oxygen and carbon dioxide Internal respiration gas exchange between blood and tissues Two zones of respiratory system Respiratory zone actual site of gas exchange bronchioles alveolar ducts alveoli Conducting zones all other respiratory passageways Upper respiratory tract Nose and nasal cavity Provides airways for respiration Moistens and warms entering air Filters inspired air and cleanses it Serves as resonating chamber for speech Houses the olfactory smell receptors Parts of the nose External nose internal nasal cavity Pharynx Connects nasal cavity and mouth to larynx and esophagus throat Three regions Nasopharynx lined with lined with stratified pseudostratified epithelium and houses the pharyngeal tonsil adenoids Oropharynx squamous epithelium located posterior to oral cavity include archway fauces between uvula and epiglottis and contain palantine and lingual tonsils Laryngopharynx passageway for food and air posterior to epiglottis Voice box attached to hyoid superiorly and inferiorly with trachea lined with stratified squamous epithelium common Composed of corniculate arytenoid cricoid and thyroid cartilage Functions Provide open airway Act as switching mechanism epiglottis to route air and food Voice production vestibular fold or false vocal chord and vocal fold or Larynx true vocal cord Trachea Windpipe Descends from larynx through neck into mediastinum and ends by dividing at carina into two primary bronchi Walls mucosa submucosa hyaline cartilage and adventitia lined with pseudostratified epithelium Branching of bronchial tree Trachea primary bronchi secondary bronchi tertiary bronchi bronchioles terminal bronchioles Trachea Bronchi Right and left primary bronchi air passages in the conduct air to and from the lungs filter air and trap particles in mucus lungs Site of conducting zone structures carry oxygen to lungs Secondary bronchi aka lobar 3 branches from right primary bronchus and 2 branches from left primary bronchus Oxygen within lobe segmental supplies bronchopulmonary segment Usually 10 in right and 8 in left muscle and no cartilage which allows for contraction and relaxation smaller tube divisions of bronchi Walls contain smooth aka Tertiary bronchioles Bronchioles Microscopic airways Terminal bronchioles Respiratory bronchioles alveolar ducts alveolar most distal segment of the conducting zone that narrowest airways of the lungs that deliver air sacs alveoli Terminal bronchioles Respiratory bronchioles branches off the lesser bronchioles to the exchange surfaces of the lungs Alveolar duct alveolar sacs Alveolar sacs such as blood carbon dioxide and oxygen exchange occurs here 300 million Alveoli tiny ducts that connect the respiratory bronchioles to the transport vital elements to your lungs and out of your lungs tiny air sacs that are at the end of the smallest airways oxygen Conducting zone bronchi Function is to for a continuous passageway for air to move in and out of the Air that reaches the bronchi is warmed cleansed of impurities and saturated lungs with water vapor The conducting zone is made up of the nose pharynx larynx trachea bronchi bronchioles and terminal bronchioles right and left primary principle bronchi branch into Secondary bronchi 3 on right 2 on left which branch into Tertiary segmental bronchi which branch into 4th 5th etc 23 orders Until bronchioles then terminal bronchioles Tissue composition of walls of primary bronchi is same as trachea but decreases in size of conducting tubes then increase in change in composition with each subsequent subdivision Cartilage rings replaced by irregular plates of cartilage Epithelium Pseudostratified then columnar then cuboidal cilia and mucus producing cells only in upper bronchioles Smooth muscle increases with decreasing size of bronchioles Site of 02 and CO2 exchange with the blood Respiratory bronchioles and alveolar ducts are responsible for 10 of gas exchange and the alveoli are responsible for the other 90 terminal bronchioles divide into respiratory bronchioles with scattered air sac outpocketing from walls branch into Alveolar ducts with sacs called alveoli chambers where bulk gas exchange Respiratory zone Alveolar sacs open into a common chamber called an atrium Air sacs alveoli provide surface area for gas exchange Respiratory membrane single layer of squamous epithelium Type I pneumocytes with pulmonary capillaries Respiratory membrane air blood barrier site of gas exchange by Diffusion requires moist membrane therefore there are cuboidal epithelium Type II pneumocytes that secretes surfactant coating gas exposed alveolar surfaces Alveoli contain alveolar macrophages that provide an immunologic occurs diffusion defense The respiratory membrane s function is to prevent each alveolus from collapsing as air moves in and out during respiration Used as a barrier across which gases are exchanged between alveolar air and the blood The barrier is made of alveolar and capillary walls The alveolar walls Respiratory gases must diffuse in order to be exchanged between the air in the alveoli and the blood this consists primarily of the type I alveolar cells Permit gas exchange by simple diffusion and secrete angiotensin converting enzyme ACE Angiotensin converting enzyme help relax blood vessels by preventing an enzyme in your body from producing angiotensin II atmospheric pressure Patm Atmospheric pressure is the pressure exerted by air surrounding the body Negative respiratory pressure is less than Patm Positive respiratory pressure is greater that Patm Breathing Pulmonary ventilation Mechanical process that depends on the volume changes in the thoracic cavity Consists of inspiration and expiration Inspiration air flows into the lungs Expiration gases exit the lungs Since gases always fill the container the larger container will have the molecules more spread out and pressure will be lower than a container that is smaller Pressure relationships Respiratory pressure is relative to Muscles of inhalation exhalation Inhalation Sternocleidomastoid scalenes external intercoastals diaphragm Process of inhalation Inspiratory muscles external intercostals contract diaphragm descends rib cage rises Thoracic cavity volume increases Lungs stretched intrapulmonary volume increases Intrapulmonary
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