Male internal genital Organ - Ductus Deferens, Seminal Vesicles & Prostate

Learning Objectives

By the end of this presentation, the students should be able to understand:

1. The gross features of male internal organs: Epididymis, Ductus Deferens, Seminal Vesicles & Prostate

2. Their blood supply , nerve supply & lymphatic drainage.

3. Know clinical correlation: Benign Prostatic Hyperplasia and clinical significance of High PSA levels.

Male Internal Genitalia

• Include.

1. Epididymis .

2. Ductus deferens.

3. Seminal vesicle.

4. Ejaculatory ducts.

5. Prostate.

6. Male urethra.

Epididymis

1. Epididymis is an organ made up of highly coiled tube.

2. At as reservoir for spermatozoa.

3. Parts .

1. Head .

2. Body.

3. Tail

4. Tail become continuous with ductus deferens.

Ductus deferens (vas deferens or deferent duct

Definition:

• Thick wall muscular tube.

• Transmit the spermatozoa from epididymus to ejaculatory duct.

• Has narrow lumen.

• Terminal dilated part called ampulla.

Location of ductus deferens

1. Length.

45 cm when straightened.

2. Course. Lies successively.

Within scrotum along the posterior border of testis.

In inguinal canal as part of spermatic cord.

Location of ductus deferens

3. In greater pelvis.

4. In lesser pelvis.

Course & relation of ductus deferens

1. Begins as continuation of tail of epididymus.

2. Along posterior border of the testis .

At 1st very tortuous .

Gradually straightens as ascend along the posterior border of testis.

Medial to epididymis.

3. In spermatic cord.

Lies vertically in posterior part of spermatic cord.

Runs upward to superficial inguinal ring.

Traverse inguinal canal.

4. Course in greater pelvis.

Leaves spermatic cord at deep inguinal ring.

Hooks round lateral side of inferior epigastric artery.

Passes backwards & medially crosses external iliac vessels.

Enter the lesser pelvis

5. Course in lesser pelvis.

Runs on lateral wall of pelvis deep to peritoneum.

Crosses the obliterated umbilical artery , obturator nerve & vessels & vesical vessels

Crosses ureter blends medially at right angle .

Enter the sacrogenital fold of peritoneum.

6. Reaching the base of urinary bladder.

7.Medial to seminal vesicle.

8. Approaches the opposite duct.

9. Reaches base of prostate

10. At base of prostate ductus deferens is joined at an acute angle by :

Duct of seminal vesicle to form ejaculatory duct.

Dilated part of ductus behind base of bladder is known ampula.

Arterial supply of ductus deferens

1. Supplied usually by terminal branch of superior vesical artery.

2. Occasionally by inferior vesical artery.

3. Anastomosis with testicular artery.

Venous & lymphatic drainage

1. Veins join the vesical venous plexus which open into the internal iliac vein.

2. Lymphatics accompany the blood vessels to nearest iliac nodes.

Nerve supply

1. Smooth muscles of ductus & seminal vesicles receive fibres from inferior hypogastic plexus.

2. They are mainly sympathetic fibres from 1st lumbar ganglion & are motor .

3. Paralysis produce sterility.

4. There is no emission or ejaculation.

Clinical Correlation

• Vasectomy:

Removal of part of vas deferens .

Done for purposes of family planning.

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

1. 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

A. Attached inferiorly to urinary bladder by ligaments

B. Posterior to pubic symphysis

C. Surrounds superior portion of urethra

D. 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 bladder

Prostatic urethra enters middle of base close to anterior surface

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

Lateral lobe

• Comprise the greatest mass of the gland

• Contain most secretory tissue

• Adenoma may arise in old age

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

a. Thin, milky, alkaline (looks like skim milk)

b. Discharged at ejaculation

c. c. Make up ~ 1/3 of semen

Age changes in prostate

Grows throughout life

Responsible for BPH

1. Small at birth

2. 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

1. Most common cancer in males

2. Metastasizes via blood (hematogenous) or lymph (lymphogenous)

3. 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 years

Thanks