The excretion of urine is carried out reflexively. Urine entering the bladder stretches its walls, irritating the receptors. Excitation occurs in them, which is transmitted to the center of urination, located in the sacral part of the spinal cord. From here, nerve impulses come to the muscles of the bladder, causing it to contract. The muscle sphincter at the exit from the bladder relaxes, urine enters the urethra and is removed from the body.
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