bladder and micturition Flashcards
3 layers of lower urinary tract
outer peritoneum, smooth muscle/CT layer, inner mucosal layer.
Female vs male bladder neck
women: muscle fiber bundles slant downward and into urethra, maintaining continence. Males: muscle fiber bundles form complete ring around neck. Combine with muscle fibers of prostate to form urethral sphincter.
- Detail the parasympathetic and sympathetic innervation to the lower urinary tract
Parasympathetic: innervate the detrusor muscle; activation results in detrusor muscle contraction and micturition. Sympathetic: Inhibit detrusor contraction and increase tension in smooth muscle of bladder neck and proximal urethra, preventing micturition until parasympathetic stimulation.
Describe motor (somatic) innervation to lower urinary tract
motor innervation of the bladder, pelvic floor, and urethral sphincter arises from segments S2-S4 of the spinal cord. Sensations of bladder fullness or stretch are conveyed through long neurons from the spinal cord to the pons.
Functions of brain stem, cerebral cortex and cerebellum in micturition
Cortex: inhibitory (diseases such as dementia, stroke, parkinsons cause incontinence). Cerebellum and brain stem are facilitatory
ventral vs dorsal root
ventral root carries motor signals from spinal cord. Dorsal root carries sensory signal to spinal cord
Storage phase and result of dysfunction
Interrelated neural and neuromuscular responses, coordinated at a number of levels. Allows bladder to adapt to increasing volume with little change in pressure. Disturbance of this phase causes frequency, urgency and urge incontinence.
Storage reflexes- afferent response and result of dysfunction
Afferent activity is generated by filling of the bladder. Sensory fibers in the pelvic nerve enters the sacral cord via the sacral DRG. Spinal cord injury and mutiple sclerosis lead to reflex reorganization (unmyelinated C fiber afferents are activated)
Afferent activity is generated by filling of the bladder. Sensory fibers in the pelvic nerve enters the sacral cord via the sacral DRG. Spinal cord injury and mutiple sclerosis lead to reflex reorganization (unmyelinated C fiber afferents are activated)
Storage reflexes- efferent response and result of dysfunction
Efferent responses to bladder filling are controlled at supraspinal levels by activating somatic (pudendal) motor neurons in anterior horn of the sacral spinal cord. These responses are associated with inhibition of the detrusor motor neuron. Also, Cortical inhibition of detrusor activity. Stroke, frontal lobe lesions, MS and spinal cord injury all impair this, resulting in detrusor overactivity.
Efferent responses to bladder filling are controlled at supraspinal levels by activating somatic (pudendal) motor neurons in anterior horn of the sacral spinal cord. These responses are associated with inhibition of the detrusor motor neuron. Also, Cortical inhibition of detrusor activity. Stroke, frontal lobe lesions, MS and spinal cord injury all impair this, resulting in detrusor overactivity.
- Overview the micturition cycle
1 Increase in 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
Describe detrusor activity, external sphincter activity and symptoms for: cortical/brainstem lesion, spinal cord injury, overactive bladder, and sacral cord/nerve root lesion
cortical/brainstem lesion: hyperactive detrusor, normal sphincter, incontinence. spinal cord injury: hyperactive detrusor, hyperactive external sphincter, dyssingergia. overactive bladder: hyperactive detrusor, normal sphincter, overactive bladder symptoms. sacral cord/nerve root lesion: complete areflexia of detrusor, normal to hyperactive sphincter, inability to void.
- Categorize the types of urinary incontinence
Stress incontinence, urge (overactive bladder), overflow,
Urodynamics
Urodynamics (UDS) is an interactive evaluation of the storage and evacuation of urine by the lower urinary tract. Videourodynamics is a technique using synchronously recorded UDS and cystourethrography. Cystourethrography adds an anatomical dimension to the study thereby obtaining a clearer understanding of complex voiding dysfunction
Define overactive bladder/ urge incontinence
Urgency, with or without incontinence, usually with frequency and nocturia, in absence of pathologic or metabolic condtion that would explain these symptoms
Behavioral therapy for urinary incontinence
fluid and dietary modification, bladder retraining, pelvic floor re-education.
Method for pelvic floor education
Kegels: most incontinent men fail to effectively contract pelvic floor muscles. Stop urine flow during urination, feel vagina tighten, do not tighten glutes or ab
Pharmacologic therapy for overactive bladder and side effects
antimuscarinic agents inhibit involuntary bladder contractions and increase bladder capacity, thereby relieving the symptoms of OAB, including urgency, frequency, and urge urinary incontinence. Limited by side effects: dry mouth, dry eyes, constipation, GERD, CNS effects
Management of refractory OAB
Intravesicular botox will inhibit vesicular neurons for up to 9 months. Injections are done on the urethra (in striated sphincter at 4 locations) and bladder ( 30-40 sites in the detrusor. Also, interstim is a neurostimulator that can be used
What is stress incontinence
·Involuntary, sudden loss of urine during increases in intra-abdominal pressure (ie. Laughing, sneezing, exercising)
Two types of stress incontinence
Hypermobility (most common) poor urethral support. Intrinsic Sphincter Deficiency poor muscle tone in the wall of the urethra (continuous leaking)
Causes of stress incontinence in women
Pelvic muscle strain, Childbirth, Pelvic muscle tone loss, Estrogen loss/menopause
DeLanceys Hammock hypothesis
In the normal continent female, ‘increases in urethral closure pressure during a stress maneuver arise because the urethra is compressed against a hammock-like supporting layer, rather than the urethra being truly intra-abdominal’
causes of stress incontinence in men
prostatectomy, radiation, neurogenic (spina bifida, pelvic fracture)
Medical management of stress incontinence
Females: alpha agonists( pseudoephedrine, ephedrine) , Estrogen. Males: Kegels, biofeedback, electrical stimulation, artificial urinary sphincter
- Overview the common causes of lower urinary tract obstruction in men
Benign prostatic hypertrophy, prostate/bladder cancer, stricture after surgery, urethral cancer, diverticulum,
male lower urinary tract obstruction symptoms
frequency, urgency, urge incontinence, nocturia, straining, decreased stream, dysuria, dribbling
