The function of the urinary bladder in a frog is to store and excrete urine, collect excess fluid and reabsorb glucose that is destined for excretion. A frogâ€™s skin must remain moist, which is why they store fluids in the bladder for later use during droughts and times of water stress.
A frog’s bladder is made up of a permeable membrane, which easily allows water to flow in and out. Essentially, it is a vascularized sac or storage unit that is sensitive to ions and regulates glucose levels. According to ResearchGate, the Rana sylvatica frog’s urinary bladder reabsorbs glucose that is destined for excretion to aid in its winter survival tactic of extreme hyperglycaemia. In other words, reabsorbing glucose, which is a form of energy, aids in the frog's survival.
Much like the mammalian bladder, the primary function of a frog’s bladder is to store and excrete urine, or toxic waste. However, a frog’s bladder also is able to move foreign or unwanted objects from other parts of the body into the bladder for excretion. According to ABC Science, a research study demonstrated that tree frogs expelled tiny beads implanted in their bodies through their urinary bladders. Tissue grows out of the bladder and captures the bead by enveloping it, then draws the bead into the bladder. Scientists believe that frogs have this adaptation because they eat insects, and sharp insect parts sometimes become lodged in the body. The bladder helps to expel them, which keeps the object from roaming around in the body.