Ch 24 Respiratory System 04 08 2010 Function of Respiratory System Permit gas exchange between air and circulating blood Conduct air to and from exchange surfaces Protect respiratory surfaces from dying Defend respiratory system from pathogens Permits verbal communication Assists in regulation of blood volumes bp and body ph Divisions The conducting part o Conducts gases to and from place where exchange occurs Respiratory part o Portion where exchange of gases occurs Components of conducting part Nose Nasal cavity and nasal sinuses Pharynx Larynx Trachea Bronchi bronchioles o Primary bronchi part are outside lungs called exobronchi o Break down into bronchioles First place where gas exchange can take place Alveolar duct Function of conducting part of respiratory system Conveying gases to and fro the exchange surface Warming the incoming air o Older people can wear masks to give more time to warm the air Filtering the incoming air removes particulate matter o Some can still get down there but want to remove the majority Humidifying the incoming air Respiratory Epithelium Lines conducting portions of respiratory system Structurally it is a ciliated psuedostratifed columnar epithelium that contains goblet cells o Goblets cells produce mucus a precursor to mucus o Columnar cells that have cilia on their surface that can move the mucus Mucociliar esculator towards the oral cavity and moves mucus to it can either be swallowed or spit out Smoking can impair it and destroy it so cannot work However if you stop smoking it can fix itself o Stem cells basal cells can repair itself or form new goblet cells or columnar cells Mucociliary escalator Washes particles toward oral cavity Heat Exchange Goes through nasal cavity to warm it and humidfy it Nose and Nasal Cavity External nares o Open to nasal cavity at vestibule o Vestibule guarded by coarse hair can be trimmed but should not be pulled out Can take bacteria from base of nose to base of skull and cause meningitis Nasal cavity o Superior middle and inferior concha Narrow grooves underneath concha are called meatuses Creates a vortex of swirling air and gives time to warm up and add humidity o Nasal cartilages Add traction to nasal cartiliages and open pathways during sporting events for a more open path way Path o External nares conchae nasopharynx entrance to auditory tube oropharynx epiglottis laryngopharynx Olfactory Region Olfactory cells that allow you to perceive smells and connect to olfactory bulb Small for humans and larger for dogs cats Components of Nasal Cavity Hard palate o Nasal and oral cavities Soft palate o Separates the nasal and oral cavities during Internal Nares Pharynx Fibromuscular tube shared by digestive Larnyx Skeleton made of cartilage o 3 paired cartilage arytenoid cartilage corniculate cartilage cuneiform cartilage o 3 unpaired epiglottis cricoid cartilage thyroid cartilage ligaments o connect to hyoid bone o connect to cricoid cartilage continues on and becomes the trachea o c shaped rings with closed part of c facing anterior Voice Longer strings produces a deeper sound o Males Shorter strings produce a higher sound Caused by vibration Causes sounds by tongue allows speech Vocal cords The glottis can open or close Trachea Tubular structure from CV6 to TV6 Main strength of wall provided by C rings of cartilage o To keep it open o Tracheal cartilage o Stiffen tracheal wall s and protect airway o Posterior wall of smooth muscle not cartilage allowing food passage through esophagus Splits into primary bronchi o To secondary bronchi tertiary bronchi Aspiration when objects are inhaled into the trachea o Often occurs in the right first Primary Bronchi Right and left primary bronchi o Trachea braches within mediastium Lobes Separated by fissure o Right lung has three lobes Superior middle and inferior o Left lungs has two Inferior and superior Lung Surfaces Costal surfaces Mediastinal surface Pulmonary Bronchi Primary bronci brach to form secondary or lobar bronchi Secondary form tertiary Branches 23x approx in a lung No more cartilage in terminal bronchioles Lead to lobules Bronchioles Usually 1 mm in diameter No cartilage in walls mainly smooth muscle for support Reduced numbers of goblets cells in epithelium and no glands in walls Variety of sies 2 important types o Terminal bronchioles slightly thicker walls o Respiratory bronchioles Alveolar organization Arrangement between alveolar ducts sacs and alveoli No possibility for gas exchange in terminal bronchioles veins lie in septum not with bronchioles intersegmental arteries follow bronchioles cell types of alveoli 2 epithelium o type 1 just sit there simple squamous not mitosis o type 2 pneumocytes septal cell can undergo mitosis produce surfactant reduces surface tension so when we exhale they don t collapse coasts foreign material to be digested by alveolar macrophages 1 phagocyte dust cells o macrophages monitor alveolar epithelium engulf foreign particles organic or inorganic gas exchange occurs in the capillary in the alveolar septum wall Respiratory membrane 4 layers blood gas barrier co2 out and o2 in pleural cavity surrounds each lung lined by pleura a serous membrane secretes a watery fluid o visceral pleura and parietal pleura o pleural fluid pleurisy Pulmonary ventilation Movement of air into and out of lungs Respiratory muscles Principal respiratory muscles are the diaphragm and intercoastal muscles o Contraction of diaphragm increases vertical As the ribs are eleveated and the diaphragm is contract the volume of the thoracic cavity increases and air moves into Accessory Respiratory Muscles Increase depth assist the diaphragm and intercoastal mm Inspiration o Ribs move upward and outward and diaphragm moves down Exhalation o Diaphragm moves up and ribs moves down Respiratory changes at birth Fetal lungs are fluid filled and collapsed Postnatal lungs are inflated and never collapse fully as long as surfactant levels are normal Respiratory distress syndrome Respiratory with age Elastic tissue deteriorates o Lowers vital capacity Movement of thoracic cage are restricted o Arthritic changes o Decreased flexibility of costal cartilages o A Commonly used term Hyperpnea o Forced breathing as in taking deep breaths or during vigorous exercise Eupnea o Quiet breathing as when sitting Tachynea o Very rapid breathing more than 20x a minute Dyspnea o Diffuculty breathing Apnea o Not breathing 04 08 2010 04 08 2010