 Section 1 of Grey's Anatomy, Part 5. This is a LibriVox recording. All LibriVox recordings are in the public domain. For more information or to volunteer, please visit LibriVox.org. Recorded by Larianne Walden. Anatomy of the Human Body, Part 5 by Henry Gray. Splankology. Under this heading are included the respiratory, digestive and urogenital organs and the ductless glands. The Respiratory Apparatus. Apparatus Respiratorius Respiratory System. The Respiratory Apparatus consists of the larynx, trachea, bronchi, lungs, and pluri. Development. The rudiment of the respiratory organs appears as a median longitudinal groove in the ventral wall of the pharynx. The groove deepens and its lips fuse to form a septum which grows from below upward and converts the groove into a tube, the laryngeotracheal tube, the cephalic end of which opens into the pharynx by a slit-like aperture formed by the persistent anterior part of the groove. The tube is aligned by endoderm from which the epithelial lining of the respiratory tract is developed. The cephalic part of the tube becomes the larynx and its next succeeding part, the trachea, while from its caudal end, two lateral outgrowth, the right and left lung buds, arise, and from them the bronchi and lungs are developed. The first rudiment of the larynx consists of two arytenoid swellings which appear, one on either side of the cephalic end of the laryngeotracheal groove, and are continuous in front of the groove with a transverse ridge, furcula of hiss, which lies between the ventral ends of the third brachial arches and from which the epiglottis is subsequently developed. After the separation of the trachea from the esophagus, the arytenoid swellings come into contact with one another and with the back of the epiglottis, and the entrance to the larynx assumes the form of a T-shaped cleft, the margins of the cleft adhere to one another, and the laryngeal entrance is, for a time, occluded. The mesodermal wall of the tube becomes condensed to form the cartilages of the larynx and trachea. The arytenoid swellings are differentiated into the arytenoid and corniculate cartilages, and the folds joining them to the epiglottis form the aryepiglottic folds in which the cuneiform cartilages are developed as derivatives of the epiglottis. The thyroid cartilage appears as two lateral plates, each contrafied from two centers and united in the mid-ventral line by membrane in which an additional center of contrafication develops. The cricoid cartilage arises from two cartilaginous centers, which soon unite ventrally and gradually extend and ultimately fuse on the dorsal aspect of the tube. J. Ernest Frazier has made an