Lung M A
Department of Physiology, Faculty of Medicine, University of Hong Kong.
J Anat. 1993 Dec;183 ( Pt 3)(Pt 3):619-30.
It is known that parasympathetic nerve stimulation elevates venous pressure in the dog submandibular gland, and that the venous pressure wave is transformed to that of the arterial pulse. The vascular arrangements and histological characteristics of the dog submandibular gland were therefore examined to establish which anatomical structures are responsible for the change in venous pressure during salivation induced by parasympathetic stimulation. The acinar and ductal circulations were found to be arranged in parallel and arteriovenous anastomoses were identified in both. Microsphere injection studies demonstrated the opening of arteriovenous anastomoses in actively secreting glands. Smooth muscle cells were rarely found in venous blood vessels but venous valves were abundant in both circulations. Dense connective tissue was observed to enclose the ductal system and its accompanying structures (blood vessels, lymphatic vessels and nerves); it was most abundant in the hilum and diminished aborally. The mechanism responsible for elevating venous pressure during parasympathetic salivation is thus probably related to opening of the arteriovenous anastomoses; the increase in the amount of surrounding dense connective tissue in a central direction may facilitate the preservation of the transmitted arterial pressure and pulse in the venous system.
已知副交感神经刺激可升高犬下颌下腺的静脉压，且静脉压波会转变为动脉脉搏波。因此，对犬下颌下腺的血管分布和组织学特征进行了研究，以确定在副交感神经刺激引起的唾液分泌过程中，哪些解剖结构导致了静脉压的变化。发现腺泡和导管循环并行排列，且两者均存在动静脉吻合。微球注射研究表明，在活跃分泌的腺体中，动静脉吻合开放。静脉血管中很少发现平滑肌细胞，但在两种循环中静脉瓣都很丰富。观察到致密结缔组织包绕导管系统及其附属结构（血管、淋巴管和神经）；在腺门处最为丰富，向口外逐渐减少。因此，副交感神经唾液分泌过程中静脉压升高的机制可能与动静脉吻合的开放有关；向中心方向周围致密结缔组织量的增加可能有助于在静脉系统中保留传递的动脉压和脉搏。
