Rommel S A, Pabst D A, McLellan W A, Mead J G, Potter C W
Marine Mammal Program, National Museum of Natural History, Smithsonian Institution, Washington, D.C. 20560.
Anat Rec. 1992 Jan;232(1):150-6. doi: 10.1002/ar.1092320117.
Cetaceans possess cryptic testes that lie within the abdominal cavity, that are surrounded by primary locomotor muscles, and that are presumably exposed to core or above core body temperatures. It has remained a question as to how cetaceans produce and store viable sperm at these high temperatures. We offer anatomical evidence for a two layer arterio-venous countercurrent heat exchanger at the cetacean testis. Subcutaneous veins from the peripheral surfaces of the dorsal fin and flukes carry cool blood from the fins to the lumbo-caudal venous plexus. The lumbo-caudal venous plexus is juxtaposed to the spermatic arterial plexus, which supplies the testis. Venous plexus flow is form the ventro-lateral margins of the visceral cavity towards the vena cava. Arterial plexus flow is from the aorta towards the ventro-lateral margins of the visceral cavity and into the testis. The existence of a countercurrent heat exchanger suggests that cetaceans potentially compensate for detrimental effects of core temperatures on sperm viability and storage by regulating the temperature of blood flow to the testis.
鲸类动物拥有隐藏在腹腔内的睾丸，这些睾丸被主要的运动肌肉所包围，并且可能暴露于核心体温或高于核心体温的环境中。鲸类动物如何在这些高温下产生并储存有活力的精子，这一直是个问题。我们提供了解剖学证据，证明鲸类动物睾丸处存在两层动静脉逆流热交换器。来自背鳍和尾鳍外周表面的皮下静脉将来自鳍的冷血输送到腰尾静脉丛。腰尾静脉丛与为睾丸供血的精索动脉丛并列。静脉丛的血流是从内脏腔的腹外侧边缘流向腔静脉。动脉丛的血流是从主动脉流向内脏腔的腹外侧边缘并进入睾丸。逆流热交换器的存在表明，鲸类动物可能通过调节流向睾丸的血流温度，来补偿核心体温对精子活力和储存的不利影响。
