Seminal vesicles and Prostate gland S-IV RM25
Learninig Objectives
At the end of the lecture student will able :
To define the seminal vesicles and prostate of male reproductive system.
Explain the relation and anatomical position of these gland.
Discuss the clinical associations of these gland
Seminal vesicles
Thin walled lobulated sacs situated b/w bladder & rectum.
Each vesicle is about 5 cm long. Applied base of bladder above prostate.
Directed upwards & laterally.
Produce 60% of seminal fluid.
Their tops are just covered by peritoneum of rectovesical pouch.
Rectovesical fascia lies behind them.
Each lies lateral to ampulla of the ductus deferens of its own side.
At lower end of ampulla behind prostate the duct of seminal vesicle join ductus to form ejaculatory ductus.
Arterial supply of seminal vesicle
Supplied by branches from.
› Inferior vesical arteries.
› Middle rectal arteries
Prostate
Definition
Accessory gland of male reproduction .
Secretion of prostate , seminal vesicles & bulbourethral glands form seminal fluid. Largest male accessory gland
Located in lesser pelvis
Gross Features:
Conical shape with:
› base (sup)
› Apex (inf),
Surfaces:
› Posterior
› Anterior
› right & left inferolateral
Relations
Attached inferiorly to urinary bladder by ligaments
Posterior to pubic symphysis
Surrounds superior portion of urethra
Anterior to rectum
Anterior Surface
Ant. Surface lies at the back of retropubic space
Connected to body of pubic bone by puboprostatic ligament.
Posterior Surface:
Post.surface lies anterior to rectum
Separated from it by retrovesical fascia(Denonvillier’s fascia)
Ejaculatory duct pierces this surface
Inferolateral surfaces are related to the inferior fibres of levator ani
Base (aka:vesicular surface): superior › Attached to neck of urinary
› Prostatic urethra enters middle of base close to anterior surface
› bladder
Apex: inferior
› Prostatic urethra emerges from front of apex to become membranous urethra
› Surrounded by sphincter urethrae
› Contacts medial margins of levator ani muscles
Capsule of prostate gland
Double Capsule:
True capsule: Formed by a thin layer of connective tissue at the periphery
False Capsule: Lies outside the true capsule and is formed by condensation of the pelvic fascia
B/W these lies the prostatic plexus of veins
Lobes of the prostate gland
Anterior lobe
Connects the two lateral lobes in front of the urethra
Contains little or no glandular tissue
Rare site for adenoma
Posterior lobe
Connects the two lateral lobes behind the urethra
Lies behind median lobe
Site of origin for primary carcinoma
Adenoma never occurs here
Median lobe
Lies posterior and superior to prostatic utricle and ejaculatory ducts
May project into urinary bladder Utricle lies within lobe
Vestigial remains of uterine homolog
Sometimes called “uterus masculinis”
Common site for adenoma
LOBES
The "lobe" classification is more often used in anatomy.
Histological zones
Peripheral zone:
Upto 70% of prostate
Surrounds distal urethra
Accounts for 70-80% of prostatic cancer
Central zone:
Upto 25% of prostate
Surrounds ejaculatory duct
Accounts for 2.5% of prostate.cancers
Transition zone:
Upto 5% of prostate area
Surrounds proximal urethra
Accounts for 10-20% of prostatic cancers
Blood supply of Prostate
Arteries derived from:
a. Internal pudendal artery
b. Inferior vesical artery
c. Middle rectal artery
Veins:a. Form venous plexus b. Drain into internal iliac veins
c. Communicate with vesical & vertebral venous plexuses
Lymphatics: a. Most terminate in internal iliac & sacral nodes (unable to palpate)
b. From posterior: to external iliac nodes
Prostatic secretions
Thin, milky, alkaline (looks like skim milk)
Discharged at ejaculation
c. Make up ~ 1/3 of semen
Age changes in prostate
Grows throughout life
Responsible for BPH
Small at birth
Enlarges at puberty
3. Maximum at about 13
4. Progressive enlargement after 40
5. Sometimes: undergoes atrophy
Benign Prostatic Hyperplasia(BPH):
Affects ~90% of men >50 years of age
Characterizied by Hyperplasia of prostatic stromal and epithelial cells
Forming discrete nodules in the periurethral region of the prostate, compressing urethra and causing symptoms of:
› urinary hesitency
› frequent urination
› Dysuria › urinary retention
BPH
Diagnosis
Rectal examination
transrectal US (TRUS)
PSA level.
Drug treatment
Alpha blockers,5 alpha inhibitors.
Surgery…..TURP(Transurethral resection of prostate). Shown in the diagram.
Prostate cancer
Most common cancer in males
Metastasizes via blood (hematogenous) or lymph (lymphogenous)
Common sites: vertebrae, pelvis
a. Via venous plexus surrounding prostate
b. Bone or direct metastasis most common
PSA (Prostate Specific Antigen)
Glycoprotein, kallikrein related serine protease
Produced by secretory epithelium, drains into ductal system
cleaves and liquefies seminal coagulum formed after ejaculation
The traditional PSA threshold level of 4.0 ng/mL is considered reasonable for further evaluation of Prostate Cancer
Annual PSA testing recommended for:
› men 50+
› men 40+ at increased risk
The age to begin screening is linked to risk: › At age 50 years for average-risk men
› At age 45 years for higher-risk men (African American ethnicity or first-degree relative with prostate cancer before age 65 years)
› At age 40 years for appreciably higher-risk men (multiple family members diagnosed with prostate cancer before age 65 years)
Prostate cancer screening is not recommended in men with a life expectancy of less than 10 year