Thisisessentialforspermproduction coolingmechanisms

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Unformatted text preview: lar Thermoregulation Sperms are not produced at core body temperature In the scrotum, the testes are kept 2­3°C cooler than in the pelvic cavity. This is essential for sperm production. Cooling mechanisms The cremaster muscle contains strips of the internal abdominal oblique muscle (skeletal muscle) around the spermatic cord. It can elevate or lower the testes. The dartos muscle is a subcutaneous layer of smooth muscle that wrinkles skin reducing surface area of scrotum. Can lifts testis upwards The pampiniform plexus is an extensive network of veins that surround the testicular artery in the spermatic cord, keeping the testes cooler countercurrent heat exchange that cools arterial blood entering testis The Scrotum The Scrotum Figure 27.2 Cremaster muscle Countercurrent Heat Exchanger Countercurrent Pampiniform plexus Connection between testis and the body body The structures that connect the testis with the body are enclosed within a connective tissue sheath called the spermatic cord Blood vessels Nerve fibers PNS and SNS Vas deferens Cremaster muscle The Testes The Testes Each testis is surrounded by two tunics: The tunica vaginalis, derived from peritoneum The tunica albuginea, the fibrous capsule of the testis Septa divide the testis into 250­300 lobules, each containing 1­4 seminiferous tubules Seminiferous tubules­ where ____ is pro...
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