(4) Micturition (SD Wang) Flashcards
What is micturition?
How your body gets rid of urine!
What is considered the upper urinary tract?
What is the considered the lower urinary tract?
Upper urinary tract = Kidney & Ureter
Lower urinary tract = Bladder, Urethra
State what type of muscle lines each sphincter
Internal Urethral Sphincter
External Urethral Sphincter
Internal Urethral Sphincter = Smooth muscle
External Urethral Sphincter = Skeletal muscle
What are the three demarcations of the trigone?
(2) Urethral openings
(1) Internal urethral sphincter
Function of the trigone?
Senses “fullness” of the bladder
Clinical Correlations:
Blockade of Urethral Outflow
Caused by?
What results?
Caused by= blockage in ureter
What results= increase in hydrostatic pressure, ureteral dilation, hydronephrosis
Clinical Correlations:
Anatomic Constrictions
Where can this occur?
Where can this occur =
- Ureteropelvic junction
- testicular/ovarian a./v.
- external iliac a./v.
- bladder wall
Clinical Correlations
Vesicoureteral Refulx
What is occuring?
Ureteral openings don’t fully close…
Leading to urine traveling back up the ureter
*Increased risk of pyelonephritis (kidney infection)
Describe the pathway for afferent (sensory) system of the bladder
Intravesical pressure stretch signals –>
Sensory nerve fibers (run w/ pelvic splanchnic n. and hypogastric plexus) –>
S2-S4 (sacral micturrition center)
What fibers transmit bladder fullness signals to the brain?
A (delta) fibers - myelinated
What fibers transmit bladder pain signals to the brain?
C fibers (unmyelinated)
Describe the efferent (motor)
PARASYMPATHETIC
What spinal level?
What nerve?
What does activation of this nerve this cause?
Neurotransmitter?
Receptor?
S2-S4
Pelvic splanchnic n.
Contraction of the detrusor m. and internal sphincter relaxation
ACh
mAChR (M3)
Describe the efferent (motor)
SYMPATHETIC
What spinal level?
What nerve?
What does activation of this nerve this cause?
Neurotransmitter?
Receptor?
L2
Hypograsteric n.
Detrusor m. relaxation and internal sphincter contraction
NE
Adrenergic
Describe the efferent (motor)
SOMATIC
What spinal level?
What nerve?
What does activation of this nerve this cause?
Neurotransmitter?
Receptor?
S2-S4
Pudendal n.
External urethral sphincter contraction
ACh
nAChR
What are the two bladder reflexes?
- Storage reflex
- Voiding reflex