BSC 2086 1st Edition Lecture 16 Outline of Last Lecture I Nonspecific Defenses II Specific Defenses III Cells and Immunity IV Immunity Disorders V Effects of Aging on Immune System Outline of Current Lecture I Introduction to Respiratory System II Components of Respiratory System III Upper Respiratory Tract IV Larynx V Trachea VI Lungs Current Lecture I Introduction to Respiratory System a Provides O2 to cells and removes CO2 that they produced b Oxygen i Obtained from air by diffusion across sensitive exchange surfaces of the lungs ii Carried by cells to cardiovascular system which brings back CO2 to the lungs c Cells make energy through mechanisms that use up the O2 and have a by product of CO2 i Energy produced is used for maintenance growth defense and division II Components of Respiratory System a Functions i Makes available extensive gas exchange surface area between the circulating blood and air ii Moves air to and from the exchange surfaces of the lungs iii Provides protection of the respiratory surfaces from the outside environment iv Makes sounds v Plays a role in olfactory sense b Organizations i Divided into 1 Upper respiratory system above larynx 2 Lower respiratory system below larynx c Respiratory tract i Conducting portion from nasal cavity to terminal bronchioles 1 Involved in ONLY moving air into and out of the lungs 2 No gas exchange occurs in this portion 3 Lined by the respiratory mucosa a Consists of an epithelial layer and an areolar layer known as the lamina propria ii Respiratory portion respiratory bronchioles and alveoli 1 Alveoli are air filled pockets found within the lungs a Gas exchange takes place here d Respiratory epithelium i In order for gases to exchange efficiently 1 Alveoli walls must be 1 m very thin a Allows for movement of gases through the walls 2 Surface are must be very big about 35 times the surface area of the body e Lamina Propria i Underlying layer of areolar tissue which supports the respiratory epithelium ii Part of respiratory mucosa in the conducting portion of respiratory tract iii Contains mucous glands that secrete onto the epithelial surface in the upper respiratory tract trachea and bronchi iv Contains smooth muscle cells that encircle lumen of bronchioles in the conducting portion of the lower respiratory system f Alveolar Epithelium i Delicate simple squamous epithelium because it is a single later of flat epithelial cells ii Mixture of scattered and specialized cells that line exchange surfaces of alveoli g Respiratory Defense System i Removes particles and pathogens through the use of filtration mechanisms 1 Mucous cells and mucous lands make the mucus that bathes exposed surfaces III IV 2 Cilia can be described as a mucus escalator which sweeps debris trapped in the mucus towards the pharynx 3 Large particles removed through filtration in nasal cavity 4 Small particles that arrive to the lungs are engulfed by alveolar macrophages Upper Respiratory Tract a Nose i Location where air enters the respiratory system ii Nasal hairs are the first filters for entering particles b Nasal cavity i Provides olfaction sense of smell ii Secretes mucous iii Tears clean and moisten nasal cavity iv Warms and humidifies air entering respiratory system 1 This step is skipped when breathing through the mouth c Pharynx i Chamber shared by respiratory and digestive system ii Extends from internal nares to the entrance of the larynx and esophagus iii Divided into 1 Nasopharynx superior portion 2 Oropharynx middle portion 3 Laryngopharynx inferior portion Larynx a Air enters larynx from the pharynx b A cartilaginous structure that surrounds the glottis i Glottis Narrow opening connecting pharynx and larynx c Cartilages i Thyroid cartilage anterior surface called laryngeal prominence aka Adam s apple 1 Largest in males due to release of testosterone ii Cricoid cartilage iii Epiglottis d Functions of the cartilage i Thyroid and cricoid cartilage support and protect the glottis and the entrance to the trachea ii During swallowing the epiglottis folds back over the glottis in order to prevent the entry of food and liquids into the trachea windpipe 1 While swallowing the larynx is elevated V VI e Ligaments i Vestibular ligaments lie within the vestibular folds 1 Protect the delicate vocal folds ii Sound is produced by the air passing through the glottis 1 Vocal folds those involved with sound are known as vocal cords vibrate a Higher pitches come from slender short folds b Low pitches come from thicker long folds Trachea a Structure i Aka windpipe ii Extends from cricoid cartilage into mediastinum where it branches into right and left pulmonary bronchi iii Submucosa 1 Under mucosa of trachea which contains mucous glands b Cartilages i 15 20 tracheal cartilages which strengthen and protect airway 1 Not continuous in the area where the trachea and esophagus are in contact 2 The C shape that it forms allows distortion in the tracheal wall for food passage into the esophagus ii The ends of the tracheal cartilage are connected by an elastic ligament and trachealis muscle 1 Diameter is reduced when trachealis muscle contracts 2 Sympathetic stimulation causes relaxation of trachealis muscle c Primary Bronchi i Right and left primary bronchi are separated by an internal ridge known as the carina ii Differences 1 Right primary bronchus is larger in diameter 2 Right primary bronchus descends at a steeper angle which is the reason for which most foreign objects entering the trachea enter the right primary bronchus Lungs a Right and left lungs are in right and left pleural cavity b The base or inferior portion of each lung rests on the top portion of the diaphragm c Lobes of the lungs are separated by deep fissures d e f g h i j i Right lung has 3 lobes ii Left lung has 2 lobes because it makes room for the heart whose apex points towards it Primary Bronchus i Branches forming secondary bronchi lobar bronchi ii Each lobe has one secondary bronchus Secondary Bronchi i Branch forming tertiary bronchi segmental bronchi Structure of Bronchi i Walls of primary secondary and tertiary bronchi contain progressively more smooth muscle but less cartilage ii An increase in smooth muscle tension will affect constriction and resistance of airways Bronchitis i Inflammation of the bronchial walls which results in constriction and difficulty breathing The Bronchioles i Formed by the branching of tertiary bronchus ii Bronchioles then branch into terminal bronchioles 1 1
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