Fourth Day. 



Arterial System (continued). 



1. Trace the carotid arch, which gives off : 



(a) Two lingual arteries having a common point of origin near the 



carotid gland. 



(b) A carotid artery passing to the head. At its origin it is slightly 



swollen into the carotid gland. 



2. Trace the systemic arches which run backwards on each side of the 

 body, meeting posteriorly to form the dorsal aorta. Each systemic arch 

 gives rise to an artery which branches into :— 



(i) A scapular artery to the pectoral girdle, 

 (ii) A cutaneous artery to the skin. 

 (iii) A brachial artery to the arm. 

 Trace the dorsal aorta backwards, and note that it gives rise to the 

 cceliaco-mesenteric artery about midway between its origin and the origin 

 of the first pair of renal arteries. The dorsal aorta then passes between 

 the kidneys giving four renal arteries to each, and proceeds backwards and 

 divides into an internal iliac artery to each leg. This artery lies between 

 the femoral and the sciatic veins. From each of these arteries a branch is 

 given off which divides into : 



(i) An iliac artery to the muscles around the ilium, 

 (ii) A cutaneous artery to the skin of the body, just anterior to the 



leg. 

 (iii) A small artery to the anterior dorsal surface of the hind limb. 



3. Trace the pulmo-cutaneous arch, which gives off : — 



(a) A pulmonary artery, running along the outer side of the whole length 



of the lung. 



(b) A cutaneous artery, which at first runs forwards to the base of the 



arm, and becomes spread out on the skin of the back of the head. 



[In the Frog 



1 . The carotid arch gives off : — 



(a) A lingual artery supplying the tongue. 



(b) A carotid artery, running round the side of the oesophagus, and 



supplying the head. At its origin it is slightly swollen into the 

 carotid gland. 



2. The systemic arches run backwards on each side of the body, and meet 



posteriorly to form the dorsal aorta. Each systemic arch gives off : — 



(a) A subclavian artery to the shoulder and fore-limb. 



(b) An occipito-vertebral artery to the head and the vertebral column. 



(c) An oesophageal artery to the dorsal wall of the oesophagus. 



(d) A laryngeal artery to the larynx. 



At the point where the dorsal aorta is formed, note the origin of 

 the coeliaco-mesenteric artery which sends branches to the stomach, liver, 

 intestine, and spleen. 



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