seminalvesicles

Question 1

what are the seminal vesicles

Answer 1

(also known as the vesicular or seminal glands) are a pair of glands found in the male pelvis, which function to produce many of the constituent ingredients of semen. They ultimately provide around 70% of the total volume of semen.

Question 2

anatomical position of the sg

Answer 2

The seminal glands are a pair of 5cm long tubular glands. They are located between the bladder fundus and the rectum (separated from the latter by the rectovesicle pouch and the rectoprostatic fascia).

Their most important anatomical relation is with the vas deferens, which combine with the duct of the seminal vesicles to form the ejaculatory duct, which subsequently drains into the prostatic urethra.

Question 3

structure of the sg

Answer 3

Internally the gland has a honeycombed, lobulated structure with a mucosa lined by pseudostratified columnar epithelium. These columnar cells are highly influenced by testosterone, growing taller with higher levels, and are responsible for the production of seminal secretions.

Question 4

embryology of the sg

Answer 4

The Seminal glands, along with the Ejaculatory ducts, Epididymis and Ductus (vas) deferens, are derived from the mesonephric ducts, the precursor structure of male internal genitalia.

These structures can easily be remembered using the acronym SEED.

Question 5

secretions of the sg

Answer 5

The secretions of the seminal gland have a key role in the normal functioning of semen, making up 70% of its total volume.

It is notable however that the first fractions of expelled semen contain mainly spermatozoa and prostatic secretions; the fluids from the seminal vesicles are included in the late ejaculate fractions. These fluids contain:

Alkaline fluid – neutralises the acidity of the male urethra and vagina in order to facilitate the survival of spermatozoa.
Fructose – provides an energy source for spermatozoa.
Prostaglandins – have a role in suppressing the female immune response to foreign semen.
Clotting factors – designed to keep semen in the female reproductive tract post-ejaculation.
The remaining volume of semen is made up of testicular spermatozoa, prostatic secretions and mucus from the bulbourethral gland.