Andrew Huberman· PhD
What you have is a muscle that is a smooth muscle tissue, unlike skeletal muscle, which is striated muscle, that is temperature dependent. So it has certain nerve endings, and it has certain receptors on it that allow it to respond to local temperature and then to relax in order to essentially let the testicles to descend further from the body or to contract and bring the testicles closer to the body in order to try and maintain the optimal temperature range.