Respiratory System Functions RESPIRATION Ventilation of the lungs breathing or use of O2 in cellular metabolism RESPIRATORY SYSTEM Organ system that rhythmically takes in air and expels CO2 from the body o Gas exchange o Communication speech and vocalization like laughing crying o Olfaction provide sense of smell o Acid base balance Eliminates CO2 that accumulates H which makes body fluids acidic o Blood pressure regulation lungs synthesize angiotensin II o Blood and lymph flow breathing creates pressure gradient between thorax and abdomen o Blood filtration lungs filter small blood clots to prevent obstructing coronary cerebral renal circulation o Expulsion of abdominal contents breath holding helps expel urine poop and children Nose Pharynx Larynx Trachea Lungs Main bronchus bronchioles alveoli Pleurae Divisions o Conducting Zone Passages for airflow from nose bronchioles Walls too thick for adequate diffusion of O2 into the blood Warm humidify cleanse Nose Pharynx Larynx Trachea Lungs Main bronchus Lobar Bronchus Segmental Bronchus Bronchioles Terminal Bronchioles o Respiratory Zone Actual site of gas exchange Upper Resp Tract Nose Larynx organs in head and neck Lower Resp Tract Trachea Lungs organs of the thorax Respiratory Bronchioles Alveolar Duct Atrium Alveolus Nostrils ant Opening posterior nasal apertures choanae pos opening Nasal Cavity internal chamber of the nose divides into halves called nasal fossae o Function Nasal Septum Dividing wall bone and hyaline cartilage NOSE o Structure Warms cleanse humidifies inhaled air Detects odors Resonating chamber that amplifies voice PHARYNX Muscular funnel from nose to larynx o Structure Nasopharynx receives auditory tubes from middle ears and houses tonsils Passes only air traps airborne pathogens Lined by pseudostratified columnar epithelium Oropharynx Space between posterior margins of soft palate and epiglottis Pass air food and drink Lined by stratified squamous epithelium Laryngopharynx Posterior to larynx Pass air food and drink Lined by stratified squamous epithelium o Function Muscles of pharynx play roles in swallowing and speech LARYNX Voice box cartilaginous chamber o Structure Epiglottis flap tissue superior to opening Extrinsic muscles of larynx pull push toward epiglottis to close airways and direct food drink into esophagus Vestibular folds Closes larynx during swallowing Vestibular ligaments as support Vocal cords folds Produce sound when air passes between them Vocal ligaments as support Covered with stratified squamous epithelium endure vibration and contact between cords Glottis Vocal cords openings between them 9 Cartilages framework Epiglottic superior spoon shaped Thyroid largest shield like Adam s Apple is ant Peak Cricoid inferior helps constitute box of voice box with Thyroid Arytenoid behind thyroid cartilage smaller in 3 pairs function in cartilage speech Corniculate pair of little horns smaller in 3 pairs function in speech Cuneiform supports soft tissues between arytenoids and epiglottis Muscular walls Extrinsic elevate larynx for swallowing intrinsic control vocal cords muscles Loudness determined by force of air passing between vocal cords Keep food and drink out of airway Produce sound NOT SPEECH MAKER TRACHEA Windpipe rigid tube in front of esophagus o Function o Structure 16 20 C shaped rings of hyaline cartilage Prevents trachea from collapsing during inhales Open C part faces posterior spanned by trachealis smooth muscle o Gap allows room for esophagus to expand as swallowed food passes by o Trachealis contract relax to adjust airflow Pseudostratified columnar epithelium lining LUNGS Conical organ o Structure Composed of mucus secreting goblet cells ciliated cells and short basal stem sells Mucus traps inhaled particles Mucociliary Escalator Mechanism where cilia drives mucus debris toward pharynx to be swallowed Adventitia outermost layer of trachea fibrous CT Carina Ridge that directs airflow to the right and left Broad concave base resting on diaphragm apex project above clavicle Costal surface pressed against rib cage Mediastinal surface faces medially Cardiac impression indent on left lung where heart presses against it Hilum slit through which lung receives the main bronchus blood vessels lymphatics and nerves structures are root of the lung Lobes 3 Right superior middle inferior 2 Left superior inferior Right is shorter than left liver rises higher on the right left is narrower because heart tilts toward left and occupies more space BRONCHIAL TREE Branching system of air tubes o Structure Main Bronchus 65 000 terminal Bronchioles Primary right main bronchus o More inhaled foreign objects lodged than left o Elastic CT Secondary Superior Middle Inferior Lobar Bronchus o Irregular cartilage plates Segmental Left main bronchus More narrow Bronchioles Continuations of airway NO SUPPORTIVE CARTILAGE Ciliated cuboidal epithelium Smooth muscle in their walls Terminal Respiratory bronchioles Final branches of conducting zone divides into 50 80 bronchioles Beginning of respiratory division because their alveoli participate in gas exchange have alveoli budding from walls given off by terminal Alveolar ducts thin walled passages with alveoli along walls nonciliated simple squamous epithelia Alveolar sacs clusters of alveoli arrayed around a central space called atrium ALVEOLI Tiny air sacs in the lungs where the exchange of oxygen and carbon dioxide takes place o Squamous type I alveolar cells thin broad cells 95 of alveolar surface thinness allows rapid gas diffusion between air and blood o Great type II alveolar cells cuboidal round 5 of surface numerous Repair alveolar epithelium when squamous cells are damaged Secrete pulmonary surfactant mix of phospholipids and protein that coats alveoli and smallest bronchioles prevents them from collapsing during exhales o Dust cells Alveolar macrophages wander lumens of alveoli and CT between them keep alveoli free of debris o Respiratory membrane barrier between alveolar air and blood o Needs to prevent fluid from accumulating because gases diffuse too slowly through liquid to sufficiently aerate blood Alveoli is dry PLEURAE Double layered membrane o Structure Visceral Serous membrane on surface of lung that extends into fissures Parietal Adheres to mediastinum inner surface of rib cage and superior surface of diaphragm Pulmonary ligament connects it to diaphragm Pleural Cavity space between visceral and parietal wrap around lung like pillowcase