BIOL226Lec11 Scrotum,Prostate

7/28/2019 BIOL226Lec11 Scrotum,Prostate

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PROSTATE GLAND


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I. Introduction/General Information

A. Attached inferiorly to urinary bladder by

ligaments

B. Posterior to pubic symphysis

C. Surrounds superior portion of urethraD. Anterior to rectum (palpation, ultrasound)

E. Conical shape


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Introduction, Prostate Gland, continued

F. Walnut sized

1. 4 cm trans x 2 cm A/P x 3 cm Sup/Inf

G. Lightly encapsulated

1. Fibrous connective tissue

2. Smooth muscle3. Capsule extends into lobes


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II. Prostate Gland: Detailed Anatomy

A. Largest male

accessory

gland

B. Located in

subperitoneal

compartment(between pelvicdiaphragm &

peritoneum)Prostate Gland, Mid-sagittal Section


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Prostate Gland: Detailed Anatomy

C. Enclosed in fascial sheath

(aka: prostatic sheath)

1. Inferiorly, sheath is continuous

with superior fascia of

urogenital diaphragm

2. Posteriorly, sheath forms part of

retrovesical septum


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Prostate Gland: Detailed Anatomy

D. Double Capsule

1. Fibrous portion contacts gland2. External capsule formed by pelvic

fascia

3. Venous plexus lies between


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Male Reproductive System, Posterior View


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Detailed Anatomy, contined

E. Conical shape with base (sup), apex (inf),

four surfaces

1. Surfaces: posterior, anterior, right &left inferolateral

2. Base (aka: vesicular surface): superior

a. Attached to neck of urinary bladder

b. Prostatic urethra enters middle of

base close to anterior surface


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Prostate Anatomy

Prostatic Urethra


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3. Apex: inferiora. Rests on superior fascia of urogenital

diaphragm muscle

b. Associated with sphincter urethraec. Contacts medial margins oflevator ani

muscles


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4. Posterior surface: triangular, flat

5. Anterior surface: narrow, convex

6. Inferiorolateral surfaces

a. Meet with anterior surface

b. Rest on levator ani fascia above

urogenital diaphragm


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F. Lobes of the Prostate

1. Divisions are arbitrary, indistinct

2. Usually divided into

a. two lateral lobesb. one median lobe

c. anterior and posterior lobes


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Lobes of the Prostate, continued

3. Median lobe

a. Lies posterior and superior toprostatic utricle and ejaculatory

ducts

b. May project into urinary bladder

c. Utricle lies within lobe1. Vestigial remains of uterine

homolog

2. Sometimes called uterus

masculinis


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4. Lateral lobes

a. Comprise the greatest mass ofthe gland

b. Contain most secretory tissue

c. Are continuous posteriorly

5. Glandular tissue with varying amounts

of fibrous tissue


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Prostate Glandin situ


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Detailed Anatomy, continued

G. Blood & lymph

1. Arteries derived

from:

a. Internal pudendalartery

b. Inferior vesicalartery

c. Middle rectalartery


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Blood & Lymph, continued

2. Veins

a. Form venous plexusb. Drain into internal iliac veins

c. Communicate with vesical &

vertebral venous plexuses


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3. Lymphatics

a. Most terminate in internal iliac &sacral nodes (unable to palpate)

b. From posterior: to external iliac

nodes (unable to palpate)


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H. Glandular tissue

1. 30 - 50 different glandular elements

a. Serous glands

b. 20 - 30 ducts empty into prostaticurethra

2. Most are posterior & lateral to urethra


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3. Prostatic secretionsa. Thin, milky, alkaline (looks like

skim milk)

b. Discharged at ejaculation

c. Make up ~ 1/3 of semen


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Detailed Anatomy, continued

I. Prostate size changes

1. Small at birth2. Enlarges at puberty

3. Maximum at about 13

4. Progressive enlargement after 40

5. Sometimes: undergoes atrophy


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III. Pathology

A. Benign

prostatichypertrophy

(BPH):

1. Affects ~90%

of men >50


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BPH, continued

2. Common cause of urethral obstruction:

causes

a. Nocturiab. Dysuria

c. Urgency

d. Back-pressure effects

e. Complete obstruction can occur


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Pathology, continued

B. Prostate cancer1. Most common

cancer in males


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2. Metastasizes via blood (hematogenous)

or lymph (lymphogenous)3. Common sites: vertebrae, pelvis

a. Via venous plexus surrounding

prostateb. Bone or direct metastasis most

common


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Prostate Cancer: Routes of Metastasis


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C. Prostatitis (accompanied by cystitis)

1. Inflammation of gland

2. Gland enlarges, becomes tender

3. Causes: gonorrhea? Other UTIs?

STDs?

4. May require antibiotics, massage5. Symptoms: chills, painful urination,

back pain


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A. Prostatic concretions (aka: corporaamylacea [starch bodies])

1. Small spherical or ellipsoid bodies

2. Number increases with age

3. May become calcified as male ages4. May simulate carcinoma


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Digital Rectal Exam


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E. Rarely, prostatic abscesses develop1. Frequently caused by gonorrhea2. May rupture through to rectum, bladder,

perineum

3. Other causes:a. Urethritis

b. Epididymitis

BIOL226Lec11 Scrotum,Prostate

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