Male accessory glands Flashcards
Seminal vesicles
What are they?
Function?
Paired, elongated, high-coiled tubular glands on the posterior wall of the urinary bladder
Function of seminal vesicles
Secrete and store seminal fluid
These alkaline secretions form 60-70% of seminal fluid and are expelled in the second fraction of the ejaculate to
- wash sperm out of the ejaculatory duct & urethra
- dilute the thick mass of sperm so they can be motile
- neutralize acidity of vagina
- energy source for sperm via fructose
Describe the seminal vesicle secretion
- Fructose - source of energy for spermatozoa
- Prostaglandins - stimulate contractions to transport sperm
- Fibrinogen - precursor of fibrin to clot the semen deep in the vagina
Appearance of seminal vesicle
- One large lumen that stores seminal fluids
- Convoluted folds in mucosa to increase secretory surface area
- Pseudostratified columnar epithelium w
- tall non-ciliated secretory columnar cells
- short, round basal cells
- simple columnar cells
- Connective tissue lamina propria w elastic fibers
- Muscularis - inner circular & outer longitudinal for ejaculation
Are there sperm in here?
no - this is the seminal vesicle (seminal fluid)
The secretory funciton and morphology of the seminal vesicles is controlled by
testosterone
What kind of epithelium do seminal vesicles have?
Pseudostratified columnar
note: basal cells at the arrows
How can you differentiate the oviduct ampulla form teh seminal vesicle?
Oviduct folds don’t connect because it wants to let the ovum through; its more round; it has peg cells
Prostate surrounds the __ just below the ___
Surrounds the urethra
Just below the urinary bladder
It’s the largest accessory male sex gland
Prostatic fluid function
-
Clotting enzymes and fibrinolysin
- Clotting enzymes act on fibrinogen from seminal vesicles -> fibrin, which clots the semen in deep vagina -> fibrinolysin breaks down the seminal clot to release motile sperm in the female tract
-
Prostate-specific antigen (PSA): serine protease to liquefy coagulated semen
- Usually very low in the blood, but
Prostate gland function
-
Secretes and stores a thin, milky, slightly alkaline fluid that constitutes 25-30% of seminal fluid
- Expelled in the first ejaculate fraction (mixed seminal + prostatic fluid in the ejaculatory duct)
- PSA, clotting enzymes, and fibrinolysin
What cells of the prostate gland produce the enzymes?
epithelial cells
PSA - clinical marker
Prostate cancer patients & Prostatitis (benign prostatic hyperplasia) have a lot of PSA misdirected into the blood
The only way to differentiate is via biopsy or rectal exam
Previously PAP was used instead of PSA as a marker for prostate cancer
Prostate gland structure
30-50 tubuloalveolar exocrine glands embedded in fibromuscular stroma and emptying into excurrent ducts that open to the urethra.
What is the brownish bluish part that makes up the majority of this photo?
Fibromuscular stroma of the prostate!
smooth muscle mixed w collagenous ct
Prostatic glandular epithelium
Has all kinds!
- Mostly simple columnar
- Patches of simple cuboidal, squamous, pseudostratified (pictured)
- Changes to transitional epithelium near opening of ducts into urethra
5a-reductase
in prostate
converts testosterone & adrenal androgens to DHT (most potent androgen)–> growth of normal prostatic epithelium and proliferation
DHT responsible for the growth of BPH and prostate cancer.
Identify
Tubuloalveolar glands
&
fibromuscular stroma (red smoothmuscle + pale ct)
= prostate gland
Prostatic concretions (corpora amylacea)
Characteristic feature of prostate in the alveoli
Concentric lamellated bodies formed by precipitation of secretory material around cell fragments
Increases w age (like brain sand in pineal gland)
How to differentiate between prostate gland and the lactating mammary gland?
Mammary gland has
- clear lobules
- no concretions, just milk
- no smooth muscle
Division of adult prostatic parenchyma into 4 zones
Peripheral zone surrounding distal urethra
Central zone surrounding the ejaculatory duct
Transitional zone surounding the proximal urethra
Periurethral zone next to proximal urethra
Prostate cancer is most common in which region of the prostate?
Peripheral zone is most susceptible to inflammation and prostate cancer - this is what we’re palpating upon digital recti exam
Because it’s only surrounding the distal urethra, early prostate cancer usually doesn’t come w clear symptoms
What zone of the prostate is responsible for benign prostatic hyperplasia (BPH) and ~34% of prostate cancers?
Transitional zone surrounding proximal prostatic urethra
–> patients have problems urinating during BPH because of the nodular masses compressing the urethra
In the later stage of BPH, the ____ zone may undergo pathologic growth but mainly from the __ compartment
Periurethral zone
Mainly stromal compartments –> worsens urethral compression & urine retention in the bladder
The fibromuscular stroma of the prostate gland is ___ connective tissue w large amts of ___muscle fibers occupying the __ surface of the prostate gland.
The fibromuscular stroma of the prostate gland is dense irregular ct w large amts of smooth muscle occupying the anterior surface of the prostate gland.
Prostate cancer review
Which side is abnormal for the prostate gland? Whats wrong?
Left side is prostate cancer - not as much stroma bc so many cells invade the basement membrane
Prostate cancer treatment
Orchiectomy (testis removal) & radiation, but hormone therapy is the best:
- GnRH agonists or antagonists to reduce circulating androgens
- Androgen receptor antagonists
Almost always leads to recurrence -> mortality
Orchiectomy
remove testis in prostate gland
low T & DHT –> high LH & FSH
GnRH antagonists and GnRH agonists in response to prostate cancer
GnRH antagonists work bc they immediately stop LH to suppress T –> low LH, T, DHT, and FSH
GnRH agonists will produce an initial surge in LH, FSH, T, and DHT, but the continuous (nonpulstaile) pituitary stimulation will downregulate and desensitize the GnRH receptor –> ow LH, T, DHT, and FSH
Cowper’s / Bulbourethral glands
function
Secrete a clear, mucus-like pre-ejaculate to lubricate the urethra for sperm transport
Neutralizes acidic urine in urethra
Flush out residual urine or foreign matter
Semen
pre-ejaculate, first fraction, second fraction
10% sperm, 90% plasma
Pre-ejaculate: bulbourethral gland
First fraction of ejaculate: sperm & prostatic fluid
Second fraction: seminal vesicle secretion
Recap on glands
contribution of excretory system to sperm production
BPH
Not all BPH pts have high PSA
BPH treatment
Remember that DHT is the main androgen at play
three erectile tissues of the penis
corpora cavernosa- 2 dorsal masses
copora spongiosum - 1 ventral mass
tunica albuginea wraps the whole thing
Corpora Cavernousa
- Contains most of the blood
- Contain numerous wide, irregularly shaped vascular spaces lined with endothelium
- Surrounded by thin trabeculae (collagen+elastic fibers+smooth muscle), which is why blood tends to go more here instead of spongiosum
-
Central artery that gives off corkscrew-shaped helicine arteries (if flaccid)
- Helicine arteries are distributed through trabeculae and open into vascular spaces; dilates during erection
corpus cavernosa
you can see corkscrew-shaped helices arteries
corpus spongiosum
spongiosum
