Department of Biological Sciences and Institute for Global Health, Vanderbilt University, VU Station B 35-1634, Nashville, TN 37235-1634, USA.
J Exp Biol. 2010 Feb 15;213(4):541-50. doi: 10.1242/jeb.035014.
The insect circulatory system transports nutrients, signaling molecules, wastes and immune factors to all areas of the body. The primary organ driving circulation is the dorsal vessel, which consists of an abdominal heart and a thoracic aorta. Here, we present qualitative and quantitative data characterizing the heart of the mosquito, Anopheles gambiae. Visual observation showed that the heart of resting mosquitoes contracts at a rate of 1.37 Hz (82 beats per minute) and switches contraction direction, with 72% of contractions occurring in the anterograde direction (toward the head) and 28% of contractions occurring in the retrograde direction (toward the tip of the abdomen). The heart is tethered to the midline of the abdominal tergum by six complete and three incomplete pairs of alary muscles, and propels hemolymph at an average velocity of 8 mm s(-1) by sequentially contracting muscle fibers oriented in a helical twist with respect to the lumen of the vessel. Hemolymph enters the heart through six pairs of incurrent abdominal ostia and one pair of ostia located at the thoraco-abdominal junction that receive hemolymph from the abdominal hemocoel and thoracic venous channels, respectively. The vessel expels hemolymph through distal excurrent openings located at the anterior end of the aorta and the posterior end of the heart. In conclusion, this study presents a comprehensive revision and expansion of our knowledge of the mosquito heart and for the first time quantifies hemolymph flow in an insect while observing dorsal vessel contractions.
昆虫循环系统将营养物质、信号分子、废物和免疫因子输送到身体的各个部位。推动循环的主要器官是背血管，它由一个腹脏心脏和一个胸主动脉组成。在这里，我们呈现了定性和定量的数据，描述了蚊子（Anopheles gambiae）的心脏。通过肉眼观察，休息状态下的蚊子的心跳频率为 1.37Hz（每分钟 82 次跳动），并且会改变收缩方向，其中 72%的收缩是向前（向头部），28%的收缩是向后（向腹部末端）。心脏通过六对完整的和三对不完整的翅肌附着在腹部背板的中线上，并通过依次收缩相对于血管腔呈螺旋扭曲排列的肌纤维，以 8mm/s 的平均速度推动血淋巴。血淋巴通过六个腹向入口和一个位于胸-腹交界处的入口进入心脏，这两个入口分别从腹部血腔和胸静脉接收血淋巴。血管通过位于主动脉前端和心脏后端的远端流出开口排出血淋巴。总之，本研究全面修订和扩展了我们对蚊子心脏的认识，并首次对昆虫的血淋巴流动进行了量化，同时观察了背血管的收缩。
