A Laboratory Guide for the Dissection of the Cat - Livres de poche

Purchase of this book includes free trial access to www.million-books.com where you can read more than a million books for free. This is an OCR edition with typos. Excerpt from book: THORACIC VISCERA. Remove the skin from the anterior part of the thorax, and cut aivay the ribs and sternum. 1. The Pleurae are the membranes which line the two sides of the thorax and are reflected over the lungs and great blood - vessels. They meet in the mid-line and form a double-walled septum, the mediastinum. The anterior part contains between its walls the heart and its pericardium. The posterior portion contains the oesophagus and blood-vessels. 2. The Lungs are the pinkish lobulated bodies lying on either side in the thoracic cavity. The lungs normally fill the entire thoracic cavity except that part occupied by the heart. When the thorax is opened they are usually found collapsed. The right lung is divided into four lobes and the left into two. The lungs may be artificially inflated to better demonstrate the lobes. 3. The Trachea may be seen, by pushing aside the heart and lungs, as a cartilaginous, annulated tube. This leads from the pharynx to the base of the lungs, where it divides into two bronchi, one of which goes to each lung and there subdivides into numerous smaller bronchi which penetrate the various lobes. 4. The Thymus Gland is the mass of glandulartissue which partially invests the trachea just anterior to the heart. It is of large size during immaturity, but atrophies in the adult. 5. The Heart is the muscular organ lying in the centre of the thoracic cavity. From the anterior part all of the great blood-vessels of the body arise. The heart is enclosed in a sac of fibrous tissue called the pericardium; this is filled with a serous fluid. The heart consists of four chambers, the two anterior called auricles, and the two posterior called ventricles. a. The Right Auricle occupies the anterior ventral portion of the heart. It consists of...