Urinary System and Urethritis
by Robert Tallitsch, PhD | November 3, 2022
Video introduction to the urinary system and explanation of urethritis. Share this video with your class!
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Written by: Robert Tallitsch, PhD
The suffix “itis” means inflammation — hence the definition of urethritis is an inflammation of the urethra. Urethritis is typically caused by a bacterial or viral infection. This Brain Builder will discuss the anatomy of the male and female urethras, followed by a discussion of urethritis, its symptoms, causes, and treatment.
The urinary system is comprised of the kidneys, ureters, bladder, and urethra. To learn about the kidneys and ureters, please refer to our Kidney Stones Brain Builder. We will begin this Brain Builder with a discussion of the male and female urethras. The urethra is a musculoelastic tube connecting the urinary bladder superiorly to the exterior environment. The passage of urine is assisted by peristaltic contractions of the smooth muscle layers lining the wall of the urethra. The anatomy of the female and male urethras differs significantly.
The female urethra is significantly shorter than the male urethra. As it moves inferiorly it curves slightly, passing through the pelvic floor to the perineum. The external urethral sphincter, which allows for the voluntary control of the passage of urine through the urethra, surrounds the urethra at this location. (The internal sphincter, which is composed of smooth muscle and controlled by the autonomic nervous system, is located at the neck of the urinary bladder in both males and females.) The urethra opens into the vestibule that lies medial to the labia minora and anterior to the vaginal opening.
The male urethra, which has three segments, moves inferiorly from the bladder, through the pelvic floor, and ends at the external urethral orifice located at the tip of the penis. The three segments, moving superiorly to inferiorly, are the prostatic urethra, membranous urethra, and spongy (penile) urethra.
The prostatic urethra is surrounded by the prostate gland, which is located at the base of the urinary bladder. The male reproductive system is connected to the urinary system at the prostatic urethra, in that the ejaculatory duct of the male reproductive system empties into the prostatic urethra. This allows sperm to pass through the urethra and exit at the tip of the penis during ejaculation.
The membranous urethra is narrow and passes through the pelvic floor. The external urethral sphincter surrounds the membranous urethra at this location.
Spongy (Penile) Urethra
The spongy urethra, which is located within the center of the penis, is surrounded by one of the erectile bodies of the penis, the corpus spongiosum. The two bulbourethral glands, which are part of the male reproductive system, empty into the spongy urethra. The external urethral orifice is located at the distal end of the spongy urethra.
In addition to the anatomical differences between the female and male urethras, there are also significant clinical differences between these two structures. One of these differences is that the female urethra contains significantly more elastic tissue than the male urethra, making it much easier to dilate. This makes the passage of cytoscopes or catheters through the female urethra significantly easier clinically than it is in the male. In addition, infection of the female urethra is more common because the female urethra is open to the exterior through the vestibule of the vagina.
Urethritis may be caused by:
- sexually transmitted disease
- bacterial infection
- viral infection
- physical injury
- sensitivity to some chemical found in spermicides and contraceptive foams and jellies
Symptoms of urethritis include inflammation of the urethra accompanied by one or more of the following symptoms:
- painful urination
- a frequent and urgent need to urinate
- difficulty starting urination
- pain during sex
- abdominal and pelvic pain
- fever and chills
Treatment of urethritis depends on the cause of the infection. Urethritis caused by a bacterial infection will be treated by a variety of antibiotics. Urethritis resulting from a viral infection, such as the herpes simplex virus, is often treated with anti-viral medications such as Famvir, Valtrex, or Zovirax.
Urethritis is preventable and curable. However, if urethritis is left untreated for a prolonged period of time it can lead to permanent damage to the urethra as well as other pelvic organs, especially in females.
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