渡辺 泱

Hiroki WATANABE

渡辺記念長命研究所

Watanabe Memorial Choumei Research Laboratory

キーワード : bladder property, UEBW, urethral opening, AFMS, bladder absorption

現行の膀胱・尿道に関する解剖学・生理学において定説とされている5件の事項について，物理学・超音波医学の立場から，次のような修正すべき提言を行った．(1)蓄尿・排尿に際して，膀胱支配神経は膀胱の物性を2段階に変換させるためのon-off制御にしか関わっていない．(2)膀胱壁の厚さ，すなわち膀胱重量は，排尿に必要な収縮力（尿道抵抗）に応じて極めて速やかかつ動的に変動している．(3)尿道の主な機能は蓄尿時における閉鎖作用より排尿時における開大作用にあり，尿道の開大効果が排尿行動を主導しているらしい．(4)男性尿道は膀胱から前立腺を貫いて連続する長大な尿道筋束を有し，従来から外尿道括約筋と呼ばれている部分はその下端部分に過ぎない．(5)膀胱は，少なくとも睡眠時にはかなりの量の尿中水分を吸収している．

With respect to five established principles in conventional anatomy or physiology of the urinary bladder and urethra, the following revisions were proposed from the viewpoint of physics and ultrasound: (1)Throughout urinary storing and micturition, only involving action from the motor neurons into the bladder may be an on-off switching between two steps of bladder property as a material. (2)The weight of the bladder (thickness of the bladder wall) varies quickly and dynamically with the change in the stress necessary for contraction (urethral resistance). (3)The main function of the urethra may not be the closure during storing but rather opening during micturition, and this opening function may control the overall micturition behavior. (4)The male urethra is surrounded by a long-ranged muscle unit throughout the prostate. The so-called “external sphincter muscle” described in current anatomy is no more than the caudal end of that muscle unit. (5)The bladder may absorb a considerable amount of water from the urine inside it, at least while sleeping.