ANATOMY AND PHYSIOLOGY 



The veins are conspicuous and dark-colored while the arteries are 

 usually colorless and inconspicuous. Can you explain this difference? 

 Arteries and veins are distributed throughout the body in a similar 

 manner. 



(b) Cut through the muscle layer a little to one side of the 

 median line and open the body cavity, or ccElom. Cut and pin back 

 the muscle layer as you did the skin in order that, the viscera, as the 

 organs of the body cavity are called, can be seen. In the region of the 

 arms it will be necessary to cut through certain bones, the arrange- 

 ment of which should be observed in a prepared skeleton. Do not cut 

 too deep and injure large blood vessels in this region. 



Exercise 4. — Identification of the Organs in the Ccelom. 



(c) In the following identification of organs they may be dis- 

 placed and pushed aside as necessary but must not be cut or removed 



reprod(Jct/Ve 

 na3o/ cay/ty t>Po/n sp/na/ corof organ A/dnei/ 





'stomach /' ' o\//ofuct 



/ ureter / c/oaca 

 / / 



anas 



tong'ua ^ , 

 £^ustochion tubel I / 



g/ottis-' l/ari}nx\ \[\\ \, \ \^^^,y^p/eeyr:S unhang b/oMer 



vocal cord-^ aunde \ . \ • > , — -■ — ^^ - \ " 



ventricle}, liver ^ pancreas 5/77a// /nt^sijne^ coe/om 



pencard/al cav/tt/ hall b/aafdcr 



Fig. 9. — The frog, shown as if cut in the median, longitudinal plane; 



semidiagrammatic . 



until specific directions are given. Work with care, and do not injure 

 structures that will be studied in detail later. Some familiarity with 

 the position of the organs can be gained from Fig. 9. 



(d) At the anterior end of the ccelom the heart will be seen sur- 

 rounded by a thin membrane, the pericardium. In a recently killed 

 frog the heart will be beating; observe how it contracts. Immediately 

 posterior to and at the sides of the heart are the three lobes of the liver. 

 Between the right and median lobes of the liver is the round, green- 

 ish gall bladder. Lift up the left lobe of the liver and find the 

 stomach, which is continuous anteriorly with a short esophagus lead- 



