NORMAL HISTOLOGY. 



CHAPTER XI. 



THE CIRCULATORY SYSTEM. 



The circulatory system includes the heart, arteries, veins, and 

 capillaries. It is derived from the mesoderm of the embryo. Its 

 nervous supply is received from the sympathetic system. The fol- 

 lowing outline exhibits the structural elements which enter into 

 its various organs : 



OUTLINE OF CIRCULATORY SYSTEM. 



Heart 



Arteries 



Veins 



Cavities . . . 



Valves 



Tunica ad- 

 ventia. . . 



Tunica me- 

 dia. . 



Tunica in- 

 tima . . 



Visceral endo- 

 thelium. 



Pericardium <j Fibrous tissue. 



| Areolar tissue. 

 [ Parietal endo- 



thelium. 



Muscular layer, or 

 myocardium { Striated fibres. 



Endocardium. . 



Auricles. 

 Ventricles. 



Elastic fibres. 

 Substantia pro- 



pria. 

 Endothelium. 



Tunica ad- 

 ventia. . 



Tunica me- 

 dia.. 



Tunica in- 

 tima . . 



( Fibrous connective tissue. 

 ( Endocardium. 



j Fibrous connective tissue. 

 ( Elastic fibres. 



j Involuntary muscle. 

 ( Elastic tissue. 



T Internal elastic membrane. 

 < Sub-endothelial tissue. 

 I Endothelium. 



f Connective tissue. 

 <j Elastic fibres. 

 ^ Smooth muscle. 



f Involuntary muscle. 

 I Elastic tissue. 



{Internal elastic membrane. 

 Sub-endothelial tissue. 

 Endothelium. 

 Valves. 



