24 MANUAL FOR STABLE SERGEANTS. 



(/) Gastrocnemius (fi^. 7). This muscle originates at the lower and 

 back of the femur and is attached to the point of the hock. At the 

 back part of the leg the tendon of this muscle becomes closely asso- 

 ciated with the tendon of the superficial digital flexor, the two form- 

 ing the tendon of achilles, or hamstring. 



Action.— To extend the hock and flex the stifle joint. 



27. Synovial membranes (synovial bursse and synovial 

 sheaths) of tendons and muscles (figs. 8, 9, 10, 11) are thin-walled 

 sacs, similar to the synovial membranes of the joints. They secrete 

 synovia for the prevention of friction and are placed at points where 

 one structure moves upon another, as where a tendon plays over a 

 bone. 



The Digestive System. 



28. The digestive organs are the mouth, pharynx, esophagus, 

 stomach, small intestine, large intestine, and anus; all lined with 

 mucous membrane. 



29. The mouth extends from the lips to the pharynx and is 

 bounded on the sides by the cheeks and above by the hard palate. 

 Its floor is formed by the tongue and other muscular tissue. Separ- 

 ating the mouth from the pharynx is the soft palate, a fleshy curtain 

 suspended from the back part of the hard palate, which permits the 

 passage of food and water from the mouth to the pharynx but pre- 

 vents its passage in the opposite direction. The lips are the organs 

 of prehension (picking up) and possess the sense of touch. The 

 tongue is a muscular organ, situated between the branches of the 

 lower jaw. It is the organ of taste and assists in the processes of 

 mastication, insalivation, and swallowing. Opening into the mouth 

 are the ducts of the salivary glands—the parotid, submaxillary, and 

 sublingual. These glands are six in number, located in pairs on 

 either side of the mouth. The pharynx, see paragraph 50. 



30. The esophagus is a muscular tube extending from the 

 pharynx to the stomach. It passes down the lower left side of the 

 neck, through the middle portion of the thoracic cavity, pierces the 

 diaphragm and enters the stomach near the front of the abdominal 

 cavity. 



31 . The stomach (fig. 13) is a hollow, pear-shaped organ, situated 

 in the anterior and left side of the abdominal cavity, behlad the 

 liver. Its internal, or mucous, coat is divided into a right and a 



