CHAPTER XIX 

 THE M TRITK >N OF THE HE MM 



THE BLOOD SUPPLY 



In cold blooded animals, such as the I 

 by blood soaking into it Prom the heart chambi hich i ? 



form definite cavities as in the mammalian heart, bul an inl 



men! of muscular tissue. In the hearts of higher animal 

 lature is supplied bj Bpecial arteri( coronar igh a • 



amount of blood may still pass directly from the card 

 the musculature through the veins of Thebesiu 



The relative importance of the various branches of tl >nary a '• 



in maintaining an adequate nutrition of the heart lias l n Btudi< 



observing the effect of occlusion of one or more of them W T P • 

 Occlusion of t 1m- circumflex branch of the left coronar} artery 

 arrest <>f the heartbeal in aboul v " per cent i 

 usually accompanied bj fibrillary contraction. Occlusii the ri 



coronary arrested the ventricular contraction in about 20 per cent 

 the cases. Smaller branches may i eluded without any evid 



change in the heartbeat. 



These results indicate thai the capillary areas supplied ! 

 of the coronary artery <h> n«.t freely anastomose with mother, l 



are more or N-ss terminal arteries; that is. each branch supplies a dist 

 region of the cardiac muscle If oi > of the smaller bi 

 nary is occluded, although there is no imme< stoppaj 



■ mi- time the area supplied by that branch usualh 

 gain indicating that collateral 

 ished I' is interesting, hoi 

 that anatomic studies have shown thai -tain amount 



CCUr hrtv. pillar: 01 hrali.-i 



• huit, from the above observations, that no adequate 

 becomi i through tins anastomosi 



PERFUSION OF HEART OUTSIDE THE BODY 



In order that the blood supply through I 

 ai lcipiat i-l\ maintain tl mnl nutrit 



