. Diseases of the heart and thoracic aorta. onnection with all parts of the body.—A TextBook of Physiology, p. 174. 30 Diseases of ike Heart. cutting it across, and stimulating its inferior (peripheral) end no effectis produced ; while stimulation of its upper (central) end causes pain,retardation of the heart, and, as I shall afterwards more particularlypoint out, such a striking diminution of blood-pressure, that the termdepressor nerve has been given to it. The inferior cardiac branch leaves the vagus below the origin of theinferior laryngeal nerve, and proceeds directly to the heart. It is
. Diseases of the heart and thoracic aorta. onnection with all parts of the body.—A TextBook of Physiology, p. 174. 30 Diseases of ike Heart. cutting it across, and stimulating its inferior (peripheral) end no effectis produced ; while stimulation of its upper (central) end causes pain,retardation of the heart, and, as I shall afterwards more particularlypoint out, such a striking diminution of blood-pressure, that the termdepressor nerve has been given to it. The inferior cardiac branch leaves the vagus below the origin of theinferior laryngeal nerve, and proceeds directly to the heart. It is acardio-inhibitory nerve, and stimulation of its inferior cut-end gives riseto the same effects as stimulation of the vagus itself { stimulation abovethe origin of this branch), viz. (with weak currents) retardation of theheart from prolongation of the diastole, and (with stronger currents)complete arrest during diastole. In the rabbit the vagus gives two branches to the heart, a superiorand an inferior cardiac branch (see fig. i6).. Fig. \i,.—The last cervical and first thoracic ganglia in the rabbit. [Left side).{SomewJiatdiagrammatic, many of tJie various brandies being omitted.)—(After Foster.) Trach. Trachea. Ca. carotid artery, sh. subclavian artery. n. Vog. thevagiis trunk, n. rec. the recurrent laryngeal, sym. the cervical sympatheticnerve ending in the inferior cervical ganglion, gl. cerv. inf. Two roots of theganglion are shown, lad., the lower of the two accompanying the vertebral artery,A. vert., being the one generally possessing accelerator properties, gl. tlior. pr. The Inhibitory Action of the Vagtis. 31 In the human subject, two branches of the vagus seemto correspond to the superior cardiac branch of the vagusin the rabbit; while the inferior cardiac branch of thevagus of the rabbit seems to be (mainly at all events)represented in man by the large branch which leaves thevagus trunk at the lower end of the neck (inferior cervicalbranch). Now it has b
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