1. What are the functions of the bladder?

• Collection and low pressure storage of urine

• Expulsion of urine at an appropriate time and place

• Aids in preventing organisms from ascending to the upper urinary tract

2. Outline the innervation of the bladder.

• PNS: the bladder's detrusor muscle has a rich parasympathetic supply that causes contraction. These nerves run from spinal segments S2, 3 and 4. It also causes sphincter relaxation

• SNS: these travel with the hypogastric nerves from L1, 2 and 3. Leads to α1 mediated contraction of the sphincter and β2 mediated relaxation of the detrusor

• These nerves combine to form a plexus at the base of the bladder

3. How is the bladder's sphincteric mechanism arranged in the male?

In males, there are two distinctive systems:

• Bladder neck mechanism: this is proximally placed. This not only provides urinary continence, but also prevents retrograde ejaculation

• Distal sphincter mechanism: this is a urethra-based system that lies at the apex of the prostate gland. This is able to maintain continence even in the face of injury to the bladder neck mechanism

4. How does this arrangement differ from that of the female?

• Bladder neck mechanism: in females, this system is poorly defined and may even be incompetent in the nulliparous

• Distal sphincter mechanism: this is relatively more important in females. It is longer than the male counterpart, extending along two-thirds of the urethra

5. At what bladder volume is the first urge to micturate felt?

150ml. At 400ml, there is a marked sense of fullness.