Ejaculation is a biological process in males involving the release of semen from the reproductive system. This event is a part of sexual reproduction, facilitating the delivery of sperm to potentially fertilize an egg. It occurs at the peak of sexual excitement.
The Mechanics of Ejaculation
Ejaculation unfolds in two phases: emission and expulsion. The emission phase involves the collection of semen in the prostatic urethra. During this stage, sperm move from the epididymis through the vas deferens. The seminal vesicles and prostate gland also contribute their fluids, mixing with the sperm to form semen.
Once semen gathers in the prostatic urethra, the expulsion phase begins with the ejection of semen from the body. This is achieved through rhythmic contractions of various muscles, including those of the urethra and perineum. Simultaneously, the bladder neck closes to prevent semen from entering the bladder. The entire process is a reflex reaction, involuntary once initiated. Sensory input from the penis, particularly the glans, transmits signals to the sacral spinal cord, triggering this reflex.
What is Semen Made Of?
Semen is a whitish-gray fluid designed to transport, protect, and nourish sperm. Its composition is a mix of secretions from several male reproductive organs. Sperm, making up 1% to 5% of the volume, originate in the testes and mature in the epididymis.
The majority of semen volume, about 65% to 75%, comes from the seminal vesicles, contributing fluids rich in fructose, a sugar that serves as an energy source for sperm. The prostate gland provides another significant portion, 20% to 30% of the volume, with its fluid containing enzymes, citric acid, and zinc. Minor contributions, around 1% to 5%, come from the bulbourethral and urethral glands, which secrete a clear, mucus-like fluid that helps to lubricate and prepare the urethra. Ejaculate volume ranges from 2 to 5 milliliters, and it initially coagulates before liquefying over about an hour, a process aided by prostatic enzymes.
Understanding Ejaculatory Variations
Variations in the ejaculatory process can occur, leading to different conditions that may impact sexual function and fertility. Premature ejaculation (PE) is a common male sexual dysfunction, defined by ejaculation occurring consistently sooner than desired, often within one minute of vaginal penetration. It can be lifelong, present from the first sexual experience, or acquired, developing after a period of normal function. Its global prevalence is estimated to be around 30%.
Delayed ejaculation (DE) is characterized by a delay in reaching climax and releasing semen, despite adequate sexual stimulation. Men with DE may require 30 minutes or longer of stimulation to ejaculate, or they might only be able to ejaculate during masturbation and not during partnered sexual activity. This condition can stem from physical causes like nerve damage or certain medications, as well as psychological factors such as anxiety or relationship issues.
Retrograde ejaculation occurs when semen travels backward into the bladder instead of exiting through the penis during orgasm. This happens because the bladder neck, a muscle that normally closes during ejaculation, remains open. While not harmful, it can cause infertility and is often associated with prostate surgery, certain medications for high blood pressure or depression, or nerve damage from conditions like diabetes or multiple sclerosis.
Anejaculation refers to the complete absence of ejaculation, even with orgasm. This condition means sperm are produced but not expelled. It can be categorized as total, where ejaculation never occurs, or situational, where it happens only under specific circumstances, such as during masturbation but not intercourse. Causes can range from nerve damage due to spinal cord injuries or neurological disorders, to psychological factors or obstructions in the ejaculatory ducts.
Painful ejaculation, also known as dysorgasmia or orgasmalgia, involves discomfort or burning sensations in the penis, scrotum, or perineal area during or after ejaculation. This symptom can range from mild to severe and may last for several hours. Common causes include inflammation or infection of the prostate gland (prostatitis), certain antidepressant medications, cysts or stones in the ejaculatory ducts, or nerve damage. Sexually transmitted infections can also lead to painful ejaculation.