Urination occurs reflexively: a signal is sent to the central nervous system from the receptors of the bladder that its walls are stretched and, therefore, a lot of urine has accumulated. As a result, a signal comes from the nervous system, forcing the walls of the bladder to contract and get rid of urine. During urination, the sphincter located between the bladder and the urethra opens. The walls of the bladder contract, and urine under pressure flows into this channel.
Remember: The process of learning a person lasts a lifetime. The value of the same knowledge for different people may be different, it is determined by their individual characteristics and needs. Therefore, knowledge is always needed at any age and position.