Others e.g. glomerulonephritis, erectile problems etc

Question 1

What is involved in the process of an erection (neurovascular phenomenon under hormonal control)

Answer 1

Arterial dilation
Smooth Muscle relaxation
Activation of the corporeal veno occlusive mechanism

Question 2

What are the 3 shafts of the penis

Answer 2

2 corpora cavernosa

Corpus spongiosum

Question 3

What covers the corpora cavernosa

Answer 3

Tunica albuginea

corpus spongiosum has a similar thinner tunica

Question 4

What is contained in the 2 Corpora Cavernosa

Answer 4

Spongy vascular erectile tissue - trabeculated smooth muscle lined by endothelial cells

Question 5

What structure is found in the Corpus spongiosum

Answer 5

Urethra

Question 6

Describe arterial supply of the penis in order

Answer 6

Internal Iliac
-Internal pudendal artery:
Dorsal penile artery, Cavernosal artery (deep penile arteries), Bulbar artery

Question 7

Describe venous drainage of the penis sinusoids

Answer 7

Subtunical plexus:

to circumflex veins to deep dorsal vein

Question 8

Describe venous drainage of the corpora cavernosa

Answer 8

Cavernous veins:

to crural veins to internal pudendal veins

Question 9

Autonomic supply of penis

Answer 9

Parasympathetic - erectile S2-4

Sympathetic - T11 to L2

Question 10

What nerve carries both types of fibres that supply penis

Answer 10

Cavernous nerve (passes posterolateral to prostate thus risk damage in prostatectomy)

Question 11

Describe physiology of flaccid state of penis

Answer 11

sympathetic tone
arterioles constricted
Sympathetic nerve terminal releases neuropeptide Y and noradrenaline
Vascular endothelium releases endothelin and prostanoids
all act on smooth muscle cells

Question 12

Describe physiology of erect state

Answer 12

Parasympathetic stimulation – arteriolar dilatation, trabecular smooth muscle relaxation
Parasympathetic nerve terminal releases Vasoactive intestinal polypeptide, Nitric oxide that act one smooth muscle cells
Parasympathetic nerve terminal also releases Acetylcholine and Calcitonin gene related peptide. ACh inhibits sympathetic nerve terminal and (like calcitonin gene related peptide) increases production of nitric oxide from vascular endothelium.
Prostanoids also secreted by vascular endothelium and act on smooth muscle cell

Question 13

Where is the central control of erections

Answer 13

Higher stimuli:
Hypothalamus, oxytocin pro-erectile pathways
Spinal reflex

Question 14

Give example of a hormone required for normal erectile function

Answer 14

Testosterone

Question 15

Examples of testosterone deficiency

Answer 15

Acquired: Primary or Secondary

Congenital e.g. Kleinfelters

Question 16

Where is problem in primary testosterone deficiency

Answer 16

Pituitary gland or Hypothalamus

Question 17

Where is problem in secondary testosterone deficiency

Answer 17

Testes - tumour, injury, drugs

Question 18

Describe the peripheral control of erections

Answer 18

Smooth muscle mediated - arteriolar dilation and trabecular relaxation
Nitrous oxide release

Question 19

Why is the release of nitrous oxide important

Answer 19

Acetylcholine effect on endothelium
In smooth muscle cell stimulates Guanylate Cyclase enzyme which converts GTP to cGMP. This then stimulates the enzyme protein kinase G (PKG) to close L-type calcium channels and open Potassium channels.
Results in decreased cytoplasmic calcium concentration and smooth muscle relaxation.

Question 20

How does phosphodiesterase work?

Answer 20

Returns penis to flaccid state

Question 21

Example if Phosphodiesterase inhibitor

Answer 21

Sildenafil (Viagra)

Question 22

Define erectile dysfunction

Answer 22

The persistent inability to attain and maintain an erection sufficient to permit satisfactory sexual performance.

Question 23

Risk factors of ED

Answer 23

Lack of exercise
Obesity
Smoking
Hypercholestrolaemia
Metabolic syndrome (diabetes at x3 risk)

Question 24

Surgical cause of ED

Answer 24

Post-radical prostatectomy

Question 25

Indicators of psychological aetiology

Answer 25

Sudden onset of ED
Good nocturnal and early morning erections
Situational ED
Younger patient

Question 26

Assessment of ED

Answer 26

Bloods and Examination often normal
Sexual Hx (International Index for Erectile Function)
Physical examination - BP, HR, Hepatosplenomegaly, Genitalia (Peyronies disease), Prostatic enlargement or cancer, Hypogonadism (small testes or other)

Question 27

Lab testing of ED

Answer 27

Fasting glucose
Lipid profile
Morning testosterone (if low then perform prolactin, FSH, LH)

Question 28

Treatment of ED (non-pharmacological)

Answer 28

Identify and treat reversible causes of ED
Lifestyle and risk factor modification
Patient and partner involvement in education and counselling

Question 29

When is ED curable

Answer 29

Hormonal causes such as testosterone deficiency, thus testosterone replacement
Psychosexual counselling (variable results)

Question 30

Treatment of ED (pharmacological)

Answer 30

Lifestyle and risk factor modification should accompany ED treatment. If a cause of ED is detected it should be treated first.
1st line = Phosphodiesterase (PDE5) inhibitors
2nd line = Apomorphine SL; Intracavernous injections; Intraurethral alprostadil; vacuum devices

Question 31

Describe physiology of first line therapy of ED

Answer 31

PDE5 inhibitors result in increased arterial blood flow, vasodilatation, and erection
Action on Nitric oxide
3 PDE5 inhibitors have been approved. Not initiators of erections – require sexual stimulation