Anatomy of urethra, ureter and urinary bladder. скачать в хорошем качестве

Anatomy of urethra, ureter and urinary bladder.

Two ureters. These narrow tubes carry urine from the kidneys to the bladder. Muscles in the ureter walls continually tighten and relax forcing urine downward, away from the kidneys. If urine backs up, or is allowed to stand still, a kidney infection can develop. About every 10 to 15 seconds, small amounts of urine are emptied into the bladder from the ureters. Bladder. This triangle-shaped, hollow organ is located in the lower abdomen. It is held in place by ligaments that are attached to other organs and the pelvic bones. The bladder's walls relax and expand to store urine, and contract and flatten to empty urine through the urethra. The typical healthy adult bladder can store up to two cups of urine for two to five hours. Upon examination, specific "landmarks" are used to describe the location of any irregularities in the bladder. These are: Trigone: a triangle-shaped region near the junction of the urethra and the bladder Right and left lateral walls: walls on either side of the trigone Posterior wall: back wall Dome: roof of the bladder Two sphincter muscles. These circular muscles help keep urine from leaking by closing tightly like a rubber band around the opening of the bladder. Nerves in the bladder. The nerves alert a person when it is time to urinate, or empty the bladder. Urethra. This tube allows urine to pass outside the body. The brain signals the bladder muscles to tighten, which squeezes urine out of the bladder. At the same time, the brain signals the sphincter muscles to relax to let urine exit the bladder through the urethra. When all the signals occur in the correct order, normal urination occurs.