Understanding Bladder Control: Sympathetic, Parasympathetic, And Somatic Nerves

Understanding Bladder Control: Sympathetic, Parasympathetic, And Somatic Nerves

Describe nerve supply to urinary bladder with a neat diagram. What is micturition reflex?
Answer:

Nerve supply of urinary bladder:

• Urinary bladder is innervated by

1. Efferent nerve supply

1. Sympathetic supply
   • Sympathetic fibres arises from the grey matter of L1L2 segments of spinal cord
   • These fibres descend down and form presacral nerve
   • Presacral nerve next divided into two hypogastric nerve which end in hypogastric ganglia Post ganglionic fibres from here supply the bladder
   • Parts innervated and its action:
   • Resultant effect is retention of urine
2. Parasympathetic supply
   • Preganglionic fibres lie in the grey matter of sacral segments of spinal cord
   • These fibres descend down and form pelvic nerve which end in hypogastric ganglia Post ganglionic fibres from here supply the bladder
   • Parts innervated and its action:
   • Resultant effect is emptying the bladder
3. Somatic nerve supply
   • Arises from the sacral segments of spinal cord
   • Passes through the pudendal nerve
   • Supplies posterior urethra and external sphincter
   • It helps during the micturition reflex as it is voluntary reflexed

2. Afferent nerve supply

Actions:

• Carries stretch sensations from bladder along parasympathetic nerve
• Carries pain sensation from bladder along sympathetic nerve

Micturition reflex:

• It consists of impulses initiated by the stretch receptors on the bladder wall, sensory signals, sacral segments of spinal cord, pelvic nerve then back urinary bladder and parasympathetic nerves

Mechanism: