Bladder and Micturition

Question 1

2 fxns of the bladder

Answer 1

storing urine

emptying urine

Question 2

Parasympathetic innervation to the lower urinary tract

Answer 2

*most imp innervation in bladder

• innervates the detrusor muscle:
  activation results in detrusor muscle contraction and peeing

HAVE TO THINK OF SPP
sacral (S2-S4) - Pelvic n - parasympathetic

Question 3

Sympathetic innervation to the lower urinary tract

Answer 3

Opp of para:

• inhibits the detrusor contraction
• Increases tension IN muscle, bladder neck, prox urethra
• everything is inhibitory (not pee)

HAVE TO THINK OF THS
thoracolumbar (T10-L1) - hypogastric n. - sympathetic

Question 4

Types of urinary Incontinence

Answer 4

1. dysfxn of storage fxn
2. unmyelination of afferents –> dont work as well –> become activated
3. Efferent dysfxn –> can no longer inhibit peeing

Question 5

Parts of the brain that are inhibitory, and facilatory in peeing

Answer 5

Inhibitory: cortex
Facilatory: cerebellum, brain stem

Question 6

How does the DRG affect peeing?

Answer 6

Bladder –> DRG –> Brain

DRG carries sensory signals to the spinal cord

Question 7

Efferent responses to bladder

Affernt responses to bladder

Answer 7

Efferent: cortical inhibition of detrusor motor neuron –> inhibits peeing

Afferent: detects stretching –> tells you to pee

Question 8

Muscles in females responsible for continence

Answer 8

Intrinsic sphincter: comprised of:

1. bladder neck muscle
2. mid-urethral complex

Question 9

Muscles in males responsible for continence

Answer 9

Intrinsic sphincter comprised of

1. bladder neck muscle
2. membranous urethra
3. smooth muscle of prostate

Question 10

Causes of incontinence in men

Answer 10

Prostatectomy
Radiation
Neurogenic

Bladder neck muscle is almost an extra sphincter.

Question 11

Causes of incontinence in women

Answer 11

• childbirth
• pelvic muscle strain
• pelvic muscle tone loss
• estrogen loss/menopause

Question 12

Common causes of lower urinary tract obstruction in men

Answer 12

• 80% have bladder obstruction in 80 yr olds
• prostate/bladder/urethral cancer
• in younger men: think urethral stricture

More common in men

• weak stream
• difficulty peeing

Question 13

Bladder muscle

Answer 13

detrusor muscle (middle layer sandwiched between outer peritoneum + inner mucosal layer)

*NOTE that the mucosal layer is making the bladder water tight

Question 14

Micturition cycle

Answer 14

1. increase in bladder wall tension
2. Afferent input overcomes the pontine micturition center threshold and provides less cortical stimulation and micturition begins
3. Pudendal nerve activity stops, the external sphincter/pelvic floor relaxes, detrusor neurons are freed and discharge
4. Proximal urethra opens
5. bladder immediately contracts

Question 15

Pontine micturation center

Answer 15

tells the brain its time to go or not time to go

Question 16

Over active bladder (OAB)

Answer 16

urgency with or w/o incontinence usually with frequency and nocturia

(in absence of path or meta condition)

Question 17

Drug to treat overactive bladder

Answer 17

Oxybutynin