Micturition Flashcards
What is the urteral-renal reflex?
blockade in ureter –> pain –> increased sympathetics –> constriction of renal arterioles –> decreased urine output –> decreased pain
What type of nerve fibers sense bladder fullness?
alpha delta myelinated
S2-S4
What type of nerve fibers sense bladder pain?
C unmyelinated fibers
S2-S4
What are the 4 anatomic constrictors that can possibly compress the ureter?
ureteropelvic jxn
testicular/ovarian A and V
external iliac A and V
bladder wall
What are the parasympathetic nerves to the urinary system?
What is the neurotransmitter and receptor?
S2-S4 = pelvic splanchnic N
Ach –> M3 receptors
What are the sympathetic nerves to the urinary system?
L2 = hypogastric N
What are the somatic nerves to the urinary system?
What is the neurotransmitter and receptor?
S2-S4 = pudendal N
Ach –> nAChR
What is the storage reflex?
through spinal cord!
bladder filling –> sends signals to spinal cord –> sympathetic and somatic outflow –> detrusor m releases and external sphincter contracts
What is the voiding reflex?
through the brain!
bladder full –> spinal cord and brain –> parasympathetic outflow and inhibition of S and somatic –> detrusor contracts and ext sphincter relaxes
What are the 3 parts of the brain that are involved in bladder reflexes?
cerebral cortex
PAG in the midbrain
PMC in the pons
What does the cerebral cortex do in bladder reflex?
interprets sensation
can partially inhibit micturition reflex by stopping PAG –> PMC signaling
What does the PAG do in bladder reflex?
receives afferent bladder signals
primary excitation input to PMC
higher brain centers can suppress or activate input of PAG –> PMC
What does the PMC do in bladder reflex?
receives signals from cerebrum and PAG
activates external sphincter relaxation and parasympathetic outflow
controls/coordinates S2-S4
