A STUDY OF BLOOD MANUFACTURE 



85 



helps to separate the lower part of the throat cavity from the 

 upper parts that commu- 

 nicate with the nose cavity. 

 The Air Passages and the 

 Epiglottis. The cavity of 

 the throat is more or less 

 conical in shape, the apex of 

 the cone narrowing below 

 into the esophagus. The 

 windpipe (tra'chea) lies in 

 front of (or ventral to) the 

 gullet and conducts the air 

 from the throat cavity to the 

 lungs. At the top of the 

 windpipe is the voice box 

 (lar'ynx). This is readily 

 felt on the ventral surface 

 of the neck and is com- 

 monly known as "Adam's 

 apple." When the food is 

 being swallowed, it is of 

 course important that the 

 windpipe be closed, and this 

 is. accomplished by a little 

 trapdoor called the ep-i-glot'- 

 tis (Greek epi= upon -{-glottis 

 = opening from the throat 

 into the larynx). If one 

 puts one's finger on the 

 larynx region and then swal- 

 lows, one can feel this organ 

 rising to meet the epiglottis. 

 Breathing and Swallowing. 

 Thus far we have de- 

 scribed five openings con- 

 nected with the throat cavity : two for the food (one lead 



FIG. 29. Longitudinal Section of 

 Head and Neck, showing Food and 

 Air Passages. 

 a = vertebral column. 

 6 = esophagus, 

 c = windpipe. 

 d = larynx. 

 e = epiglottis. 

 / = soft palate and uvula. 

 g = opening of left Eustachian 



tube. 



h = opening of left tear duct. 

 i = hyoid bone. 

 k tongue. 

 I = hard palate. 

 m, n = base of skull. 

 >P>Q = upper, middle, and lower 

 turbinate bones. 



