title: Physiological considerations of the morphologic changes of the testicles during erection and ejaculation: a canine study.
abstract: OBJECTIVE
  We investigated the hypothesis that testicles and scrotal skin undergo morphologic changes that would serve the mechanism of erection and ejaculation.
  
  
  METHODS
  Testicular and scrotal skin changes during erection and ejaculation were studied in 9 dogs. Testicular volume was measured by ultrasound, testicular temperature by digital thermometer and testicular vascularity by color duplex Doppler ultrasonography. Dartos muscle activity was studied by electromyography.
  
  
  RESULTS
  Testicular volume increased during erection and diminished at ejaculation. Testicular consistency became softer during erection and firmer at ejaculation. During erection and ejaculation the testicles were elevated closer to abdominal wall. Testicular temperature increased in the erectile phase followed by reduction during ejaculation. Doppler ultrasonography recorded increased testicular vascularity during erection and diminished vascularity at ejaculation. A dartos muscle electromyogram exhibited increased activity in the erectile and ejaculatory phases.
  
  
  CONCLUSIONS
  During erection and ejaculation, testicles underwent changes which apparently serve the erectile and ejaculatory functions of penis.
authors.affiliation: Department of Surgery and Experimental Research, Faculty of Medicine, Cairo University, Cairo, Egypt. shafik@ahmedshafik.com
authors.forename: Ahmed
authors.initials: A
authors.lastname: Shafik
authors.forename: Ali A
authors.initials: AA
authors.lastname: Shafik
authors.forename: Ismail A
authors.initials: IA
authors.lastname: Shafik
authors.forename: Olfat
authors.initials: O
authors.lastname: El Sibai
mesh_terms: D000818:Animals; D001831:Body Temperature; D004285:Dogs; D004542:Ejaculation; D004576:Electromyography; D008297:Male; D009119:Muscle Contraction; D010410:Penile Erection; D012611:Scrotum / Q000033:anatomy & histology / Q000502:physiology; D013737:Testis / Q000033:anatomy & histology* / Q000098:blood supply / Q000000981:diagnostic imaging / Q000502:physiology*; D018615:Ultrasonography, Doppler, Color