Male Reproductive System

https://sciencewithsusanna.com has diagrams, notes, and practice questions. Quizlet: https://quizlet.com/_6qh8ot The scrotum contain the testes. The scrotum has muscles that can adjust how close the testes are held to the body wall; for sperm development they need to be 3 degrees cooler than body temperature. Testes: produce sperm within seminiferous tubules. Testosterone causes the development of sperm. FSH and LH from the pituitary gland regulate testosterone production in the testes. Epididymis: sperm mature and are stored here Vas Deferens: Tube that sperm travel through to join the urethra. Clipped during a vasectomy as a permanent method of birth control. Seminal Vesicles: Produce the majority of the semen. Contents are alkaline to protect the sperm from the acidity of the female's vagina, the seminal fluid also contains fructose to nourish sperm for up to 5 days, and a sticky protein that allows the semen to stick to the cervix. Prostate Gland: smooth muscles contract just before ejaculation to close off the upper portion of the urethra so that urine cannot leave at the same time as sperm. Also adds some fluids to the semen. The prostate gland may enlarge with age and squeeze on the urethra, preventing urination despite a full bladder. Bulbourethral/Cowper's Gland: produces an alkaline pre-ejaculate that neutralizes the acidity of the urethra so that the sperm are not damaged leaving the body. During sexual arousal, parasympathetic nerves dilate blood vessels in the penis, allowing the corpus cavernosum to engorge with blood and become erect. Erectile Dysfunction is often treated with medications that dilate these blood vessels. Sympathetic nerves cause rhythmic contraction of smooth muscles that cause semen to leave the body. Ejaculate contains about 2-5mL of fluid and contains about 200 million sperm.