Urethra in Human Anatomy and Physiology

We can understand the Uthera as a thin tube or a duct that interlinks the urinary bladder to the urinary meatus so that urine can pass out from both males and females. The urethra function is only for urinating in females, but males use their urethra for ejaculation and urination. In other words, the male urethra transports both urine and semen. The female urethra is about 1.5 inches long, and the female urethra is as long as the penis – about 7 to 8 inches in length. The urethra is held by the urethral sphincter – a muscular structure that helps keep urine in the bladder until voiding can occur. Now that we have touched the basics of the urethra function let us dovetail into its other nitty-gritty.

To answer the question – what is urethra – with adequacy, we have to analyze the organ's functions deeply. The primary urethra function is to let the urine pass from the bladder out of the body. It happens when the brain tells the bladder that it is time to squeeze and the splinter muscle relaxes, releasing the urine through the urethra. Likewise, the exact mechanism is also used in cases of male ejaculation during copulation. When males ejaculate, the sperm is carried through the urethra. The primordial difference between urination and ejaculation is that in the latter, instead of the brain, bladder sphincter muscle communicating, men have nerves in the spinal cord, vas deferens, seminal vesicles, and prostate that work in conjunction to close the opening of the bladder. They work together to enable the semen to move down the penis and through the urethra. Now let us explore the anatomy of the urethra.

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Urethra Anatomy

• The Male Urethra – It is divided into four parts as per the location. The first part is the pre-prostatic urethra. It is the intramural part of the male urethra engulfed by the urethral sphincter and ranges from 0.5 and 1.5 cm in length, depending upon the fullness of the bladder. After that, we have the prostatic urethra. It starts at the neck of the bladder and is located in the prostate. It is the widest part of the urethra and is surrounded by a sphincter muscle that holds the urine until its due time. After that, the spongy urethra makes up the bottom portion of the urethra, which has several subdivisions like the bulbous and penile urethra. The penile urethra is the most extended section of the urethra and runs from the urogenital diaphragm to the penis top. It is noteworthy to highlight that all parts of male urethra have their supply of arteries that facilitate blood flow. The prostatic urethra utilizes the inferior vesical artery. The membranous urethra uses the artery located at the penis' bulb. The spongy urethra utilizes the pudendal artery found deep in the pelvis.

• The Urethra Female – To begin with, the female urethra anatomy is far more straightforward than its male counterpart. The female urethra covers less distance, and hence it is less complex. It starts at the bladder and parallels along the pelvic floor. It opens onto the perineum after passing through the sphincter muscle. The female urethra comprises three layers – muscular, erectile, and mucous layer. The female urethra, as we have already mentioned, is about 4 cm long. It exists between the clitoris and the vagina and extends from the internal to the external urethral orifice. 

Anatomical Variations in Male and Female Urethra 

We can observe congenital conditions in some people's urethra that inhibit its functions. Among men, the urethra opening may not be at the top of the penis, resulting in a condition known as hypospadias. It has to be corrected surgically during infancy or early childhood. Sometimes, the urethra is shorter than its desirable size, and other times there may be a blockage of the urethral stricture. Other conditions related to the urethra include its infection that results in purulent urethral discharge. Cancer can also develop along the lining of the urethra.

Top 4 Facts of the Human Urethra

• To begin with, the length of the urethra varies across genders. The length of the female urethra is usually around 4 to 5 cm, whereas the male urethra is 20 cm or longer.

• The job of the female urethra is solely to facilitate urination. On the contrary, the responsibility of the male urethra is urination and ejaculation.

• The voluntary control associated with urination comes from the striated muscle known as the external urethral sphincter.

• Urethral cancer is a rare cancer type found only among 1 or 2 people diagnosed with cancer. There are different types of urethral cancer, such as adenocarcinoma, transitional cell carcinoma, and squamous cell carcinoma. 

In conclusion, we have tried to aptly answer the question – what is urethra – and examine its various functions. All human body organs have their integral role, and the slight malfunction of one organ or even one single cell can wreak havoc.