Urinary Continence and Renal Pain Flashcards
What nerve fibres give sensory innervation?
Somatic sensory = sensations from body wall
Visceral afferent = sensations from organs
What nerve fibres give motor innervation?
Somatic motor = motor responses to body wall and stimulate skeletal muscle to contract
Parasympathetic/sympathetic = stimulate smooth and cardiac muscle and glands
What nerves modalities control ureteric peristalsis and bladder contraction?
Sympathetic and parasympathetic
What nerve modalities are responsible for urethral sphincter control?
Sympathetic and parasympathetic = internal sphincter
Somatic motor = external sphincter, levator ani
What nerve modality is responsible for the perception of pain from the kidneys, ureters and bladder respectively?
Visceral afferent nerve fibres
What nerve modality is responsible for pain from the urethra?
Visceral afferent in pelvis
Somatic sensory in perineum
What nerve modality is responsible for pain from the testes?
Visceral afferents with some somatic presentation also
What modalities are involved in the voluntary control of urinary elimination?
Sympathetic, parasympathetic, somatic motor, visceral afferent
Where do the lumbar and sacral plexuses supply?
Perineum and lower limbs = supply both somatic motor and sensory
How many pairs of spinal nerves are there?
31 pairs in total = 12 pair of cranial nerves
What is the only way any type of nerve fibre can communicate with the CNS?
By being carried within the cranial or spinal nerves
Where do sympathetic fibres leave the CNS?
Within spinal nerves between T1-L2 (thoracolumbar outflow) = join somatic motor and sensory fibres
How do sympathetic fibres reach the smooth muscle and glands of the body wall?
Within spinal nerves
How do sympathetic fibres reach the smooth muscle and glands in the body?
Within the splanchnic nerves = cardiopulmonary or abdominopelvic
How do sympathetic fibres reach the head?
Follow the arteries which supply the same structure
What level do sympathetic fibres leave the cord at to supply the urinary system?
Between T10-L2 levels = enter sympathetic chain bilaterally but don’t synapse
What do sympathetic fibres leave the sympathetic chain with when travelling to supply the urinary system?
Abdominopelvic splanchnic nerves
Where do sympathetic fibres synapse when travelling to the urinary system?
Synapse at the abdominal sympathetic ganglia = located around the abdominal aorta
Where do post-synaptic sympathetic fibres pass to once they leave the abdominal sympathetic ganglia?
Pass onto the surface of the arteries which head towards the organs
What is a peri-arterial plexus?
Collection of nerve fibres found on the outside of arteries = also contain parasympathetic and visceral afferent fibres
How do parasympathetic fibres leave the CNS?
Within four cranial nerves = CN III, VII, IX and X
Within the sacral spinal nerves
Do parasympathetic fibres supply the smooth muscle and glands of the body wall?
No = supply smooth muscle and glands of head and body
How do parasympathetic fibres reach the hindgut and pelvic organs?
Via pelvic splanchnic nerves = also carried briefly within sacral spinal nerves
What cranial nerve carries parasympathetic fibres to the kidneys and ureters?
Vagus nerve (CN X)
What nerves innervate the bladder?
Pelvic splanchnic nerves = S2-4
Where do somatic motor fibres supply?
Only structures of the body wall
What parts of the renal system receive somatic motor fibres?
Only parts within the perineum = urethra distal to the pelvic floor, external urethral sphincter, levator ani
What are some nerves that carry somatic motor fibres to the urinary system?
S2-4, pudendal nerve
Where is pain from the kidney felt?
Dull, achy pain felt in loin = posterior aspect of flank on affected side, usually felt in dermatomes
Where is pain from the bladder felt|?
Midline in the suprapubic region = dull, achy pain
Where is pain from the perineal part of the urethra felt?
Quite localised in the perineum
Where is pain caused by a calculus obstructing the ureter felt?
Radiates from loin to groin on affected side
Where is pain from the distal urethra felt?
Localised within perineum = sharp pain
Where is pain from the testes felt?
Often felt in scrotum but can radiate to groin and anterior lower abdomen
Where do visceral afferent fibres from the kidney travel?
Run alongside sympathetic fibres back to spinal cord = enter spinal cord between T11 and L1
What are some differentials for loin pain?
Skin origin (e.g shingles), muscular pain, vertebrae pain, spinal nerve root compression, lower lobe pneumonia
Where do visceral afferent fibres from the ureters enter the spinal cord?
Between T11 and L2 level = pain may be felt anywhere along their path
What are some differentials of groin pain?
Hernias (inguinal, femoral), lymphadenopathy, testicular pathology
What part of the bladder do visceral afferent fibres carry pain from?
The part that touches the peritoneum = return to spinal cord at T11-L2 level
Where do visceral afferent fibres from parts of the bladder not touching the peritoneum enter the spinal cord?
Run alongside parasympathetic fibres back to spinal cord between S2-4
What are some differentials of supra-pubic pain?
Hindgut organ pain, other single midline pelvic organs whose superior aspect touches the peritoneum
What part of the urethra do visceral afferent fibres innervate?
Proximal urethra (above levator ani and in pelvis) = run alongside parasympathetic fibres back to spinal cord at S2-4 level
Where do somatic sensory fibres that supply the areas of the urethra not innervated by visceral afferent fibres enter the spinal cord?
Carried within pudendal nerve to S2-4 level = pain localised in perineum
What are some differentials of perineal pain?
Vaginal tear, anal canal fissure, perineal genital ulcers
Why do visceral afferent fibres from the testes run alongside the sympathetic fibres?
Due to their embryological descent = enter spinal cord at T10-11
Why can pain from the testes sometimes be felt in the L1 region?
Due to their close relationship with the scrotal wall = pain may be localised to scrotum or groin
What are the differentials of scrotal pain?
Skin lesions, strangulated inguinal hernia
What level of the spinal cord is essential in controlling urine flow?
S2-4
What modalities are present at S2-4 level?
Visceral afferents entering
Pelvic splanchnic nerves (parasympathetic) leaving
Pudendal nerves formed at this level = carry somatic sensory and motor nerve fibres
What happens when the bladder fills?
Sensed by stretch receptors at end of visceral afferent fibres = relayed to CNS at S2-4 levels
What bladder reflex only occurs in males?
Reflex to empty bladder by stimulation of detrusor muscle and inhibition of internal sphincter muscle
Why are adults and potty trained children able to over-ride reflexive bladder voiding?
Have action potentials within inhibitory nerve fibres from the cortex which pass inferiorly
What are adults able to do in regards to the bladder that infants cannot?
Voluntarily contract external sphincter and levator ani muscles
What happens when an adult decides to void their bladder?
Detrusor contracts (parasympathetic) Internal urethral sphincter (parasympathetic), external urethral sphincter and levator ani relax (somatic motor)
Why do the anterolateral abdominal wall muscles contract during bladder voiding?
Increases intra-abdominal pressure and forces urine out of the external urethral orifice = under somatic motor control
What forms nerve plexuses?
Anterior rami of spinal nerves
What nerves does the sacral plexus give rise to?
Pudendal nerve = S2-4
Sciatic nerve = L4-S3
What are some nerves given off by the lumbar plexus?
Iliohypogastric and ilioinguinal nerves = L1 level
Lateral cutaneous nerve of the thigh = L2-3 levels
Femoral and obturator nerves = L2-4 levels
Genitofemoral nerve = L1-2 levels
What structure is the femoral nerve located under?
The inguinal ligament = supplies anterior compartment of thigh, becomes saphenous nerve
What structure does the obturator nerve pass through to supply the medial compartment of the thigh?
Obturator foramen
How does the sciatic nerve reach the posterior compartment of the thigh?
Goes via the gluteal region = splits into tibial nerve and common fibular nerve
Where does the tibial nerve supply?
Posterior compartment of leg and intrinsic muscles of foot
Where does the common fibular nerve supply?
Deep branch = anterior compartment of leg
Superficial branch = lateral compartment of leg
What nerves form the sural nerve?
Tibial and common fibular nerves = supplies sensation to lateral aspect of foot
What supplies the first web space of the foot?
Deep fibular nerve
What supplies sensation to the plantar aspect of the foot?
Tibial nerve
What controls ureteric peristalsis?
Automatic action initiated and propagated by ureteric cells which have their own auto-rhythmicity
What controls bladder contraction?
Parasympathetic fibres from S2-4 via pelvic splanchnic nerves stimulate detrusor muscle to contract
What causes the internal urethral sphincter to contract in males?
Stimulation by sympathetic fibres = occurs during ejaculation
What causes the internal urethral sphincter to relax?
Stimulation by parasympathetic fibres = allows urine to flow through urethra
What causes the external urethral sphincter to contract?
Somatic motor fibres within the pudendal nerve (S2-4)
What causes the levator ani to contract?
Somatic motor fibres within the nerve to levator ani (S3-4)
