CIRCULATORY SYSTEM. 



Heart. 



Heart: (a) Pericardium, exhibiting endothelial layers and intervening fibrous 

 tissue; (b) Myocardium: (c) Endocardium, with its elastic fibres, substantia pro- 

 pria and endothelium; (d) Annuli flbrosi; (e) Anastomosing striated fibres; (f) 

 Nucleus; (g) Valve. 



A. Artery. B. 'Capillary and Vein. 



A. Artery: (a) Tunica adventitia; (b) Tunica media: (c) Tunica intima. 



B. Vein : (a) Tunica adventia; (b) Tunica media; (c) Tunica intima; (d) 

 Capillary. 



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