Watch the next lesson: https://www.khanacademy.org/test-prep/nclex-rn/rn-reproductive-system-physiology/rn-reproductive-system/v/anatomy-of-the-male-reproductive-system?utm_source=YT&utm_medium=Desc&utm_campaign=Nclex-rn Missed the previous lesson?https://www.khanacademy.org/test-prep/nclex-rn/rn-integumentary-system-physiology/rn-integumentary-system/v/thermoregulation-by-muscles?utm_sourceā¦