Bowel and bladder control involve spinal reflex arcs that are located in the sacral region of the spinal cord. In both instances two sphincter muscles, an internal sphincter of smooth muscle and an external sphincter of skeletal muscle, control the passageway out of the body. How would a transection of the spinal cord at the L1 level affect an individual's bowel and urinary bladder control?
What will be an ideal response?
487) In this case the defecation (bowel) and micturition (urinary) reflexes would still exist. This is because the reflexes are controlled at the sacral level, and damage to the cord is in the lumbar region. However, voluntary control of such reflexes would be lost, since the voluntary control of the external sphincters originates in the cerebral cortex. In this case the axons of the upper motor neurons connecting to the lower motor neurons are severed. The individual
would therefore have no voluntary control over defecation and urination, similarly to a newborn.
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