Econ 101 1st Edition Exam 3 Study Guide Lectures 17 25 Lecture 17 March 9th Function Larynx is intrinsic part of respiratory system o role is protective 1 prevent air from escaping from lungs 2 prevent foreign substances from entering lungs 3 expel foreign substances threatening trachea non biological role is as sound generator only when not performing biological role o holding breath when lifting heavy object to make accessory muscles concentrate their strength in lifting by fixing up the rib cage in held breath Reflex response Larynx cannot be used in both sound generation vibrating and eating closed Framework Framework Hyoid bone actually supportive structure for root of tongue but suspends larynx and serves as attachment for extrinsic laryngeal muscles unique bone only bone in larynx system in that not attached to any other bone of skeleton o does not articulate with any other bones o everything else are cartilages o 3rd or 4th cervical vertebra held in position by complex system of muscle and ligament situated in neck at level of C3 with greater cornu directed posteriorly number of muscles run between root of tongue and hyoid bone Larynx hanging onto hyoid bone Greater cornu directed posteriorly Lesser cornu directed superiorly Framework Thyroid Cartilage largest laryngeal cartilage thyroid lamina angle of thyroid superior thyroid notch superior and inferior thyroid cornu horn Framework Cricoid cartilage shaped like signet ring located immediately above upper tracheal cartilage forms lower border of laryngeal framework arch quadrate lamina plate articular facets Framework Arytenoid cartilages paired cartilages on sloping border of quadrate lamina roughly resemble three sided pyramid muscular process vocal process vocal ligament o not part of arytenoid cartilage but attached to it o extends from each vocal process of arytenoid to the angle of thyroid meet at this point apex arytenoid thyroid cricoid cartilages are all hyaline cartilages May become bone like with aging Framework corniculate cartilages small bead like cartilages that cap each arytenoid no real importance Framework Epiglottis flexible leaf like structure o elastic cartilage located just behind hyoid bone and root of tongue attached inferiorly to thyroid angle thought to prevent food from entering larynx during swallow o flip down during swallow Cuneiform Cartilages embedded in aryepiglottic folds o membrane stretching between side of epiglottis and apex of arytenoid cartilage help support folds stiffen them to maintain opening to larynx no role in sound production Joints Cricoarytenoid saddle diarthroidial joint o moveable permits rocking and some gliding or sliding rocking movements of arytenoids moves vocal processes up and out or down and in Regulate opening and closing of vocal folds arytenoid is the moving structure Joints Cricothyroid pivot diarthroidial joint allows for decreased separation between thyroid and cricoid cartilages in anterior midline changes characteristics of vocal folds Lecture 18 March 11th Membranes Ligaments Extrinsic outside of larynx o connect laryngeal cartilages to external structures Intrinsic o interconnect laryngeal cartilages and help regulate extent and direction of their movements Extrinsic hyothyroid membrane attaches superior border of thyroid to body and greater horns of hyoid bone includes middle and lateral hyothyroid ligament o fill in the space between thyroid and hyoid bone o flexible soft tissue membrane Extrinsic Hyoepiglottic ligament attaches superior aspect of epiglottis to body of hyoid bone Extrinsic Cricotracheal membrane connects lower border of cricoid cartilage to upper border of first tracheal ring Intrinsic Cricovocal of vocal ligament membrane also known as conus elasticus continuous sheet that connects thyroid cricoid and arytenoid cartilages middle cricothyroid ligament connects cricoid cartilage to thyroid cartilage at the angle lateral cricothyroid membranes form lateral portions of conus elasticus originate from superior border of cricoid fibers terminate as free thickened margins from vocal process of arytenoid to thyroid angle called vocal ligament o prevent air escape o direct air to the tube in between the vocal ligament Intrinsic Quadrangular membranes arise from lateral margins of epiglottis and thyroid angle course posteriorly and inferiorly to medial surfaces of arytenoids terminate inferiorly as free thickened margins called ventricular ligaments terminate superiorly as aryepiglottic folds Laryngeal Cavities Supraglottal superior border is aditus laryngis entrance to larynx o triangular opening bounded by epiglottis anterior aryepiglottic folds lateral and arytenoid apex posterior pyriform sinus is deep depression lateral to aditus laryngis cavity vestibule lies below aditus laryngis o bounded inferiorly by ventricular false vocal folds ventricle lies just below ventricular folds glottis space in between the vocal ligaments o area between vocal folds Laryngeal Cavities Subglottal from vocal folds to lower border of cricoid cartilage vocal folds originate at anterior commissure attach to vocal process at posterior commissure variable sized opening between folds called glottis false vocal folds squeeze together when you want a tight larynx Lecture 19 March 13th Extrinsic Muscles one attachment to structures outside larynx o ie hyoid bone responsible for support and fixation of larynx in neck Suprahyoid and Infrahyoid Suprahyoid lies above the hyoid bone Digastric Stylohyoid Mylohyoid Geniohyoid Digastric paired muscle each consisting of 2 fleshy bellies o Anterior Belly Origin lower border of mandible near midline Course inferior and posterior Insertion lesser horn of hyoid via intermediate tendon o Posterior Belly Origin mastoid process of temporal bone Course inferior and anterior Insertion lesser horn of hyoid via intermediate tendon o Action raise hyoid bone Intermediate tendon take anterior and posterior belly to connect with hyoid o Elevated hyoid o Mandible has to be fixed o Stylohyoid long slender muscle lying just superficial to posterior belly of digastric Origin styloid process of temporal bone Course parallel to posterior belly of digastric Insertion body of hyoid bone at junction with greater horn Action draw hyoid bone superiorly and posteriorly Elevate hyoid posteriorly and superiorly Mylohyoid thin sheet of muscle fibers forming muscular floor of mouth Origin inner surface of mandible from mental symphysis to last molar