How does scrotum regulates the temperature of testes?
There are three mechanisms for regulating the temperature of the testes:
- Dartos muscle
- Cremaster muscle
- Pampiniform plexus
Dartos muscle
- This is a subcutaneous layer of smooth muscle.
- When scrotum is exposed to cold temperature, this muscle contracts.
- This makes the scrotum tight and wrinkled.
- This action holds the testes closely against the warm body and reduces the surface area of the scrotum, thus reducing the heat loss.
Cremaster muscle
- This is an extension of the internal oblique muscle that descends through the spermatic cord.
- When the scrotum is exposed to cold temperatures, cremaster muscle contracts and draws testes closer to the body to keep them warm.
- On the contrary, when scrotum is exposed to warm or high temperature, cremaster muscle relaxes and the testes are drawn farther from the body.
Pampiniform plexus
- This is an extensive network of veins from the testes.
- These veins surround the testicular artery in the spermatic cord.
- The plexus prevents warm arterial blood from overheating the testis,which would inhibit sperm production.
- It acts as a countercurrent heat exchanger.
- Blood ascending the testes is relatively cool, about 35℃ and absorbs heat from the warmer blood, about 37℃ descending through the testicular artery.
- By the time the arterial blood reaches the testis, it is 1.5 to 2.5 degrees cooler than it was when it left the pelvic cavity.
Other articles: - Scrotum FAQ
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