Physiology of the Urinary Tract - McCormick Flashcards
What pathways carry conscious bladder sensations?
Afferent pathways
Parasympathetic fibers function?
Which nerve?
Via pelvic splanchnic n
Stimulate detrusor m
Inhibit contraction of internal urethral sphincter
Sympathetic fibers function?
Which nerve?
Via the hypogastric n
Inhibits detrusor constriction
Constricts internal urethral sphincter
Somatic motor neurons function?
Which nerve?
Via pudendal n - Voluntary
Constrict external urethral sphincter
Pontine micturition center
Pons
Descending impulses control SMC and thoracolumbar sympathetic outflow
Coordinates activity
How does urine travel in ureter?
Peristalsis
Supplied with parasympathetics (increase) and sympathetics (decrease)
As radius of the bladder increases, what happens to wall tension and pressure?
Wall tension increases
T = Pr/2
Pressure stays the same preventing prolapse
When bladder stretch receptors are activated, what happens in SMC?
Activates parasympathetics
When bladder stretch receptors are activated what happens in brainstem/cerebral cortex?
Suppress parasympathetic impulses
During later bladder filling, parasympathetic impulses from sacral cord lead to?
Stimulate bladder contraction and inhibit contraction of internal urethral sphincter
Student Doctor Lee has been on a 3 month bender in preparation for her impending wedding. She needs to drink alcohol to make her tolerable to others. On a Friday night, right before her Renal final, she has decided to numb the pain. She imbibes a 12 pack of Natural Light. As she crawls across the KCU parking lot she feels the need to micturate. How does her bladder empty when she feels it let go, ruining her Louis Vuitton shoes?
Passively.
