Urinary bladder collects in the bladder, fed from the two ureters that connect the bladder with the kidneys. Urine leaves the bladder via the urethra, a single muscular tube ending in an opening – the urinary meatus, where it exits the body. Anatomists divide the bladder into:. The apex (prev."vertex") is directed forward toward the upper part of the pubic symphysis, and from there the median umbilical ligament continues upward on the back of the anterior abdominal wall to the umbilicus. The peritoneum is carried by it from the apex on to the abdominal wall to form the middle umbilical fold. The
Ludwieg tube Ludwieg tube A Ludwieg tube is a cheap and efficient way of producing supersonic flow. Mach numbers up to 4 in air are easily obtained without any additional heating of the flow. With heating, Mach numbers of up to 11 can be reached. A Ludwieg tube is a wind tunnel that produces supersonic flow for short periods of time. A large evacuated dump tank is separated from the downstream end of a convergent-divergent nozzle by a diaphragm or fast acting valve. The upstream end of the nozzle connects to a long cylindrical tube, whose cross-sectional area is significantly larger than