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Flashcards in Bladder & Micturition Deck (30):

What begins the lower urinary tract?



What are the 3 layers of the bladder?

Outer peritoneum

Layer of smooth muscle and connective tissue (detrusor muscle)

Inner mucosal layer


What's the difference between the bladder neck (intrinsic sphincter) muscle fibers between men and women?

Women have bundles that slant downwards into the urethra that are instrumental for maintaining continence.

Men have muscles that form a complete ring around the neck. Together with smooth muscle fibers of the prostate, they form the urethral sphincter.


Does the bladder have smooth or skeletal muscle?



What does the rhabdosphincter muscle do?

Skeletal muscle that can close the urethra if you want to stop peeing.


What is micturition?



Is the control of micturition autonomic or CNS?

Both. It involves both autonomic and CNS systems


What is the most important innervation of the lower urinary tract?

Parasympathetic nerve fibers that innervate the detrusor muscle. Activation results in detrusor muscle contraction and micturition.

If you don't have this, you can't urinate.


What does sympathetic innervation do for the lower urinary tract?

Sympathetic activation inhibits the detrusor muscle contraction and increases tension in the smooth muscle of the bladder neck and proxima urethra, preventing micturition until parasympathetic stimulation occurs.


Explain the motor (somatic) innervation of the lower urinary tract

S2-S4 controls the bladder, pelvic floor, and urethral sphincter. Sensations of bladder fullness or stretch are conveyed through long neurons from the spinal cord to the pons.

"S2, 3, 4 keeps the penis off the floor"


Explain this diagram *know this*

The S2-4 gives rise to pelvic nerves and pudendal nerves. The pudendal nerves are the somatic innervation that control the external urethral sphincter and muscles of the pelvic floor. The pelvic nerves are the parasympathetic innervation for the bladder.


T10-L2 gives rise to hypogastric nerves which give sympathetic innervation to the bladder.


The cortex of the brain is predominantly inhibitory. How can damage to the cortex effect micturition?

Loss of central cortical inhibition over sacral centers occurs in diseases like dementia, stroke, parkinsonism. This causes incontinence.


When you have the urge to urinate due to bladder filling, the cortex is what allows your to say "no". Damage to this causes incontinence.

Babies don't have a fully developed cortex and that's why they don't have the inhibition either.


The dorsal root carries ____ signals to the spinal cord and the ventral root carries _____ signals from the spinal cord.

sensory, motor


The bladder is made of smooth muscle and can expand to hold more volume. If there is a problem with storage function, what 3 things occur?

What happens if there is a problem with voiding function? What 3 things can occur?

  • Storage function problems
    • increased frequency of urination
    • increased urgency
    • urge incontinence
  • Voiding function problems
    • Hesitancy
    • Weak stream
    • Incomplete bladder voiding


Explain the afferent and efferent responses of storage reflexes for the bladder.

Afferent activity is generated by filling of the bladder. Sensory fibers in the pelvic nerve enters the sacral cord via the sacral dorsal root ganglion.

Efferent responses to bladder filling are controlled at supraspinal levels by activating somatic (pudendal) motor neurons in the anterior horn of the sacral spinal cord. These responses are associated with inhibition of the detrusor motor neuron with cortical inhibition of detrusor activity.


What are the 5 steps of the micturition cycle? Do they have to be in order?

*know this*

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

These must be in this exact order.


What is incontinence and how is this an issue?

It is the unintentional release of urine. It can be embarrassing and unpredictable.

Causes patients to:

  • avoid an active lifestyle
  • shy away from social situations
  • constantly search for the nearest bathroom
  • become too embarrassed to talk to their doctor


What past history is significant for incontinence?

Diabetes mellitus (diabetic neuropathy)

Bowel problems/constipation

Neurological disorders

Past surgical history (e.g. radical pelvic surgery, prostatectomy, spinal surgery, bladder outlet procedures)


What is urodynamics?

It's an interactive evaluation of the storage and evacuation of urine in the lower urinary tract. It is one with a catheter.


What physical exercise can be done to help incontinence?

Kegel exercises


What are the main agents for pharmacologic therapy for over active bladder?

Antimuscarinic agents. Oxybutynin

Remember "No pee, no see, no spit, no shit"


Oxybutynin is a tertiary amine that is a smooth muscle relaxant that facilitates bladder storage.


How can botox (botilinum toxin) be used to treat over active bladder?

Botox can be injected into the bladder which causes paralysis. However, it's not permanent so you have to do it from time to time


What is stress urinary incontinence?

Involuntary, sudden loss of urine during increases in intra-abdominal pressure

E.g. laughing, sneezing, coughing, exercise or even routine activity.


Do men or women typically get stress urinary incontinence? Why?


It is usually from childbirth causing pelvic muscle strain and tone loss. It can be from estrogen loss from menopause.


What drugs can be given to help with increasing bladder outlet resistance for women with stress urinary incontinence?

  • Alpha-agonists (e.g. phenylpropanolamine, pseudoephedrine, ephedrine)
    • modest effect in minimal SUI
    • systemic side effects include HTN, anxiety, and arrhythmias
    • possible interaction with estrogen
  • Estrogen


What is the most common cause of urinary tract obstruction in men?

Prostate (usually benign hypertrophy).

Can also be prostate or bladder cancer or stricture from surgery or trauma but the most common is benign prostate hypertrophy.


What are symptoms of male lower urinary tract obstruction?

  • storage symptoms
    • frequency
    • urgency
    • urge incontinence
    • nocturia
  • emptying symptoms
    • hesitancy
    • straining
    • decreased stream
    • dysuria
    • dribbling


True or False: benign prostate hypertrophy (BPH) is a problem that happens with aging


By age 80, 80% of males will have BPH and 50% will be symptomatic.

At age 50, 25% of men have BPH and numbers increase w age


How do you treat BPH?


  • alpha receptor blockers to decrease tone



Urethral stricture in younger men is usually from