The detrusor urinae muscle, also detrusor muscle, muscularis propria of the urinary bladder and (less precise) muscularis propria, is smooth muscle found in the wall of the bladder.
Frequency is the number of occurrences of a repeating event per unit time. It is also referred to as temporal frequency, which emphasizes the contrast to spatial frequency and angular frequency. The period is the duration of time of one cycle in a repeating event, so the period is the reciprocal of the frequency.
The number of cycles in a second is one Hertz (Hz), after the German physicist. Therefore 1Hz equals one cycle per second. Period: the time it takes to complete one cycle. (see Figure 03) Figure 03. Wavelength: The distance sound travels during one period, regardless of frequency.