Which part of the prostate is affected by BPH? What are the implications of this?
Middle lobule of Prostate
Compresses urethra = dysuria, nocturia, urgency
Describe the difference in PSA levels between BPH and prostatic malignancies:
BPH = normal or slightly raised PSA
Prostatic malignancies = markedly raised PSA
In which 2 ways does prostatic cancer commonly metastasise?
1) via lymph - to internal iliac and sacral nodes
2) via venous blood - to internal vertebral plexus - to brain and vertebrae
Which lobe of the prostate is palpated during a DRE?
Posterior lobe of prostate
To which lymph nodes does prostatic cancer metastasise to first?
- Internal iliac nodes
- Sacral nodes
Name the 3 erectile tissues present in the root of the penis:
2 x crura (of corpora cavernosum)
1 x bulb (of corpus spongiosum)
Name the 2 muscles in the root of the penis:
What is the function of the bulbospongiosum muscle, and in what part of the penis is it found?
- Expels last drops of urine from penis
- Maintains erection
- Root of penis
What is the function of the ischiocavernosum muscle, and in what part of the penis is it found?
- Compresses veins, maintaining an erection
- Root of penis
Name the 3 erectile tissues present in the body of the penis:
2 x corpora cavernosum
1 x corpus spongiosum
Which erectile tissue of the penis surrounds the urethra?
Th expansion of which erectile tissue forms the glans of the penis?
Name the arteries which lie either side of the corpus spongiosum:
Name the arteries which run through the middle of each corpora cavernosum muscle:
Deep arteries of the penis
Which part of the urethra is the least distensible, and why?
- Due to surrounding sphincter urethrae muscle, and perineal membrane
What is the arterial supply to the penis?
Internal pudendal artery (from int. iliac) forms:
- Dorsal arteries of penis
- Deep arteries of penis
- Bulbourethral arteries
What is the venous drainage of the penis?
- The cavernous spaces drain into venous plexuses, into the deep dorsal veins of the penis
- Skin and cutaneous tissue drains into superficial dorsal veins
Name the fibrous tissue which envelopes the corpora cavernosum:
How does an erection occur?
- Vasodilation of coiled arteries of the corpora cavernosum increases blood flow
- Tunica albuginea resists expansion, occluding the venous plexuses in the penis
- Contraction of bulbospongiosus and ischiocavernosus also occludes venous plexuses
= Penis becomes ingorged with blood = increased pressure
Where do the lymphatics of the penis drain to?
- Into deep inguinal nodes (femoral triangle)
Which nerves innervate the penis?
Sensory + Sympathetic = Dorsal nerve of the penis (Pudendal nerve) S2-4
Parasympathetic = Pelvic nerve S2-4
Which nerve causes ejaculation?
Dorsal nerve of the penis (Pudendal nerve) L1/2
Which nerve causes erection?
Pelvic nerve S2-4
List some physical causes of erectile dysfunction:
- Vasculogenic: CVD/hypertension/diabetes
- Neurogenic: MS/Parkingsons/Stroke
- Hormonal: Hypogonadism/Thyroid disease
- Anatomical: Peyronie’s disease
List some pharmacological causes of erectile dysfunction:
List some psychological causes of erectile dysfunction:
- Abuse-related conditions
How does viagra result in erection?
- Inhibits cGMP breakdown in corpora cavernosum
= NO stimulated vasodilation