Human Reproduction and Development The Male and Female Reproductive Systems
The Male Reproductive System – External Structures EXTERNAL ORGANS - The external organs produce, store, and release the sperm. VOCABULARY 1. Penis – Contains 3 cylinders of spongy, erectile tissue that fill with blood during sexual arousal, causing an erection. The glans is the highly sensitive tip of the penis. 2. Scrotum – Inside are 2 testicles. Maintains testes at a temperature of about 5 degrees F BELOW core body temperature (93F). This is the best temperature for sperm production. Male Reproductive SystemMale Reproductive System- Diagrams
Internal Organs - The internal organs are a series of glands and ducts that store, nourish, and transport the sperm cells once they are produced. VOCABULARY 3. Testicles (testes) – Produce sperm and manufacture the male hormone, testosterone. Testosterone is mainly responsible for development of the male secondary sexual characteristics such as facial and body hair, deepening voice, and broadening of shoulders.
More internal structures… 4. Epididymis – Once fully formed, the sperm produced by the testes move into a tightly coiled tube called the epididymis that curves over the top of each testicle. Sperm mature here while they are stored. 5. Vas deferens – From each epididymis, the sperm travel into a tube called the vas deferens. This tube carries sperm up into the body prior to ejaculation.
6. Seminal Vesicles – a pair of glands that produce a seminal fluid used to provide nutrients to the sperm and increase their mobility. 7. Prostate gland – The 2 vas deferens empty into a single tube that passes through a chestnut-shaped structure called the prostate gland. The fluid contributed from the prostate increases mobility and helps protect sperm against the acidic environment of the vagina. 8. Cowper’s glands – These 2 glands secrete preejaculatory fluid that lubricates the urethra and neutralizes any acid that may remain in the urethra after urination. IT IS POSSIBLE FOR A PREGNANCY TO OCCUR FROM PREEJACULATORY FLUID!
9. Urethra – Tube that starts at the bladder and runs through the penis to its end. It carries urine and semen out of the body, but these substances do not mix because of the sphincter, which is a valve that closes off the bladder during an erection.
Possible Problems with the Male Sexual Organs 1. Cryptorchidism (undescended testicles)- During fetal development, the testes develop in the abdominal cavity of the male fetus. In 2%-4% of male births, 1 or both testes fail to descend. TREATMENT: In most cases, the testicles descend by themselves before puberty. Others are treated with surgery and/or hormones before the age of Phimosis – In this condition, the foreskin is so tight that it cannot be pulled back to expose the glans. Diagnosis usually occurs at puberty; extremely painful erection. TREATMENT: Circumcision (cutting of foreskin)
More possibilities… 3. Testicular Torsion – rare condition that occurs when the testicle twists out of normal position, causing a kink in the vas deferens. Extremely painful. TREATMENT: Untwisting of the testicle (needs to be immediate). 4. Epididymititis – inflammation of the epididymis, most often caused by the STI chlamydia. TREATMENT: Antibiotics 5. Testicular Cancer – Most common type of cancer in men aged Curable if treated early. TREATMENT: Depends on how far along cancer is. Medication, removal of tumor, removal of testicle, or combination.