ANATOMY IX A NUTSHELL. 



245 



oblique vein from the back of the left auricle which is the remnant of the obliter- 

 ated left vena cava called duct of Cuvier. This great coronary sinus ends in 

 the right auricle between the inferior vena cava and the auriculo-ventricular 

 opening. The opening of this sinus is guarded by a semilunar fold of the lining 

 membrane of the heart called the coronary valve or Thebesii. 



7. Venae Thebesii are minute veins which drain the cardiac muscular sub- 

 stance and open directly into the right auricle by the foramina of Thebesii. 



LESSON LXVII. 



Nerve Supply. — The nerves to the heart are derived from the cardiac 

 plexuses, formed by the pneumogastric and sympathetic nerves. Its actions 

 are involuntary. The nerves of the heart are derived from three sources: 



PLATE XCIX. 



UPPER INTER- 

 VERTEBRAL NOTCH 



SUP.ARTICPROC'S. 

 TRANSVERSE 

 PROC'S. 



OEMIFACET FUR HEAD OF RIB. 

 LOWER INTERVERTEBRAL NOTCH. 



A Dorsal Vertebra, With Long Spine. 



1. From nerve cells buried in its own substance and known as the intrinsic 

 ganglia. 



2. From the tenth pair (pneumogastric) of cranial nerves. 



3. From the sympathetic nervous system. 



The intrinsic ganglia keep the heart beating, and the other two sets of 

 nerves control the rate and force of the beat. 



Systole is contraction of the heart and arteries tor propelling the blood 

 and thus carrying on circulation. The expansion of the hearl is called diastole. 



The heart has two sounds. The first is longer in duration and lower in pitch 

 than the second. It is made by those sounds which take place during ventri- 

 cular systole. (1) Muscular contractions. (2) friction of blood rushing through 



