1 62 RESPIRATION 



Abnormal Respiration. The term eupnea is used to de- 

 scribe normal, tranquil breathing. Apnea is suspended res- 

 piration. Hyperpnea is exaggerated respiration. Dyspnea 

 is labored breathing. Asphyxia is essentially a want of O 

 characterized by convulsive respirations, and later by irregu- 

 lar shallow breathing. The last two named deserve some at- 

 tention. 



Dyspnea may be due to either a deficiency of O or an ex- 



FIG. 51. The heart in the first stage of asphyxia. 



The left cavities are seen to be distended; the left ventricle partly overlaps 

 the right; La., left auricle; l.v., left ventricle; a, aorta; p.a., pulmonary artery; 

 p.v., pulmonary vein; r.a., right auricle; r.v., right ventricle; v.c.d.. descending 

 vena cava; v.c.a., ascending vena cava. (Kirkes after Sir George Johnson.) 



cess of CO2 in the blood. When an animal is made to 

 breathe in a small, confined space the amount of O soon be- 

 comes insufficient even though the amount of CO2 in the 

 blood be not increased. Again, if an animal be caused to 

 breathe air containing the usual amount of O and a large 

 amount of CO2, it will suffer from dyspnea also. In either 

 case the manifestations are practically the same slow, deep 

 and labored respiration. In cardiac disease, hemorrhage, 

 pulmonary diseases, etc., dyspnea is from lack of O in 

 the tissues, because of enfeebled action of the heart, deficient 



