MRS - Seminal vesicles Flashcards
What is the function of the seminal vesicles?
They have a key role in the production of normal functioning semen.
The fluid from seminal vesicles are included in late ejection fractions. These fluids contain:
1) Alkaline fluid - neutralises the acidity of the male urethra and vagina, in order to facilitate the the survival of the spermatozoa.
2) Fructose - provides an energy source for the spermatozoa.
3) Prostaglandins - has role in suppressing the immune response of the female reproductive system.
4) Clotting factors - designed to keep the spermatozoa in the female reproductive tract post-ejaculation.
Anatomical position and structure?
These are glands that are located between the bladder fundus and the rectum (separated from the latter by the rectovesicle pouch and the rectoprostatic fascia).
The most important anatomical relation is the vas deferens, which combines with the duct of the seminal vesicles to form the ejaculatory duct, which subsequently drains into the prostatic urethra.
Internally, the gland has a honeycombed, lobulated structure with a mucosa lined by pseudostratified columnar epithelium. The columnar cells are highly influenced by testosterone, growing taller with higher levels, and are responsible for the production of seminal secretions
Embryology?
The seminal glands, the epididymis, the ejaculatory ducts and the ductus (vas deferens) are derived from the mesonephric ducts, the precursor structure of the male internal genitalia.
The acronym SEED can be used to remember this.
Vasculature?
The arteries are derived from the:
1) inferior vesicle
2) internal pudendal
3) middle rectal
All of these stem from the internal iliac artery.
Innervation?
It is sympathetic in origin.
Memory aid: Point and Shoot to remember this. Erection, or pointing, receives parasympathetic innervation, while ejaculation (including the smooth muscle of the seminal vesicles) is sympathetic innervation.
Lymphatics?
Drainage of this gland is into the external and internal iliac lymph.
Clinical relevance - seminal gland abscess?
Inflammation of the seminal vesicles (also called vesiculitis or spermatocystitis) may result after microbial infection of the urethra and prostate gland. Symptoms such as vague perineal pain or penile pain, discomfort during ejaculation and haemospermia (blood in the ejaculate) are suggestive of such infection.
Treatment consists of proper antibiotic regimens. In rare cases, obstruction of the seminal vesicle duct may lead to abscess formation. In such cases, paracentesis is the mainstay treatment. Drainage of these abscesses may be facilitated by transrectal ultrasound (TRUS) guided aspiration.
Clinical relevance - examinationa and investigation?
Physical examination of the seminal glands via DRE is difficult.
A laboratory investigation examining the fructose content of the seminal vesicle may provide indirect evidence of the seminal vesicle dysfunction, obstruction or congenital absence.
