18 



THE FROG 



the frog and in man. Make comparisons with the drawing of air 

 in and out of a pipette and with the pumping up of a tire. Why is it 

 that a man can breathe through either his nose or mouth but the frog 

 can breathe only with its mouth closed? 



(d) Remove the esophagus, the lungs, the floor of the mouth 

 cavity, and the lower jaw by lifting up the end of the esophagus where 

 it was cut from the stomach and carefully cutting the attaching struc- 

 tures as you pull ; cut at the corners of the mouth as necessary. With 

 scissors, separate the removed piece into right and left halves by a 

 cut passing through the glottis and exactly along the mid-line. Ob- 



o/facfory /ode. 

 fro/7 fa/ s/nas 



^:y}G/')(yct// 3/nc/s 



mou/h coi^/Zc/ 

 /jard joo/afe. 

 ^r>grc/e 



f/o///5 

 voco/ 



cerebro/ /^em/sp/iera 



/)c/popfyys/s 

 c//enospiho/Qn 

 (//7/rc/ \^€nfr/ois) 



cerede//o/T7 

 -^L/ri'/j ye/7/r/c/3 



/??ecy(y//<7 

 £>o/'/- pc/Zo/iz 

 ep/^/o///s 



sp/na/ conjf 



esop/7c^s 



fnDC/'>iso^ 



Fig. 18. — The human head, showTi as if cut in the median, longitudinal plane; 



semidiagrammatic. 



serve the size and shape of the larynx as seen from the inside, and 

 find the openings into the lungs. The vocal cords are ribbonlike 

 structures attached to the side walls of the larynx. How do they 

 function? Compare this dissection with "half-frogs" prepared by the 

 instructor. Make a drawing ( X 3) of your dissection as seen from 

 the cut surface. Indicate by arrows the course of the air from the 

 outside to the lungs. Cut one lung lengthwise and observe its folded 

 lining. What are the functions of the lungs? 



