In the primitive form a single anterior aorta is given off from the ventricle, the two together representing the dorsal blood-vessel of Chaetopods.
To the left of the vena cava is the Spigelian lobe, which lies in front of the bodies of the tenth and eleventh thoracic vertebrae, the lesser sac of peritoneum, diaphragm and thoracic aorta intervening.
In more specialized forms a posterior aorta passes backwards from the ventricle, as in Gastropods and the majority of Lamellibranchs.
The aorta gives off a large branch (the anterior aorta) very near its origin, from which arise - first, the left axillary, and afterwards the right axillary and the two carotid arteries.
A, View of the heart of a dog infested with Filaria immitis Leidy; the right ventricle and base of the pulmonary artery have been opened: a, aorta; b, pulmonary artery; c, vena cava; d, right ventricle; e, appendix of left auricle; f, appendix of right auricle.
The blood leaves the heart past three semi-lunar valves, by the right aorta, this being alone functional, a feature characteristic of, and peculiar to, birds.
The dorsal vessel is prolonged anteriorly into an aorta, through which the blood is propelled into the great After Miall and Denny, The Cockroach, Lovell body-cavity or haemoReeve & Co.
" Amyloid " occurs as a pathological product, and also in the healthy aorta and in old cartilage.
The heart is not contained in the pericardium, lies dorsad of the rectum and gives off a single aorta anteriorly.
- Shell globular, covering only a small portion of the vermiform body; heart on ventral side of rectum; a single aorta; siphons long, united and furnished with two posterior calcareous " pallets."
Both present the appearance of diminutive clusters of grapes, at the anterior end of the kidneys, close to the suprarenal bodies, separated from each other by the descending aorta and by the vena cava where this is formed by the right and left vena iliaca communis.
The heart in Patella consists of a single auricle (not two as in Haliotis and Fissurella) and a ventricle; the former receives the blood from the branchial vein, the latter distributes it through a large aorta which soon leads into irregular blood-lacunae.
Scorpio certainly comes nearer to Limulus in the high development of its arterial system, and the intimate relation of the anterior aorta and its branches to the nerve centres and great nerves, than does any other Arthropod.
Welch produced oedema of the lungs experimentally by increasing the pressure in the pulmonary vessels by ligature of the aorta and its branches, but this raised the blood pressure only about one-tenth of an atmosphere, while in some of Loeb's experiments the osmotic pressure, due to retained metabolic products, was equal to over thirty atmospheres.
- Spinal ganglion -Spinal nerve Aorta- From A.
B, buccal mass; m, retractor muscles of the buccal mass; ov, ovary; od, oviduct; i, coils of intestines; ao, aorta; c', left auricle; c, ventricle.
The aorta is not independent as in Chitons, but is a sinus like the other channels of the circulation.
In short, the single corporeal element of the Ionian physicists was, to borrow a phrase from Aristotle, a permanent aorta having 7r1cOrj which change; but they either neglected the iraOn or confounded them with the oboia.