Malpighian tubules are specialized structures found in the digestive systems of many arthropods, including most insects, that handle excretion and osmoregulation. The tubules are typically arranged in pairs and have a convoluted structure that increases their surface area.

Animals have evolved different strategies for excretion, the removal of waste from the body. Most waste must be dissolved in water to be excreted, so an animal’s excretory strategy directly affects its water balance.

After spending 3 to 10 hours in the large intestine, chyme loses a lot of water and becomes feces, the final product of digestion. Feces consist of undigested dietary fiber such as cellulose, mucus, sloughed-off epithelial cells, and microbes. The descending and sigmoid colon stores feces and uses haustral contractions to dry it out but retains enough water to give it a semi-solid texture.
The mass peristalsis then pushes the feces into the rectum, which stretches the rectal walls to activate...

The gastrointestinal elimination process involves a complex interplay of neural and hormonal mechanisms that coordinate the final waste removal from the body. This intricate operation encompasses the absorption of water and electrolytes, vital for transforming the remaining indigestible food matter into feces. The large intestine is pivotal in water and electrolyte absorption, forming feces from unabsorbed minerals, undigested food, bacteria, bile pigments, and shed epithelial cells. Essential...

Organisms must keep bodily fluids at a constant temperature and pH while maintaining specific solute concentrations in order to support life functions. Osmoregulation is the process that balances solute and water levels.

Urination, or micturition involves the coordination of the bladder's detrusor muscle and two sphincters to ensure controlled bladder emptying.
The process begins with bladder filling, where the bladder wall stretches as urine accumulates. This stretching activates the urine storage reflex, mediated by the sacral spinal segments and the pontine storage center. Efferent sympathetic impulses stimulate the detrusor muscle to relax and the internal urethral sphincter to contract, facilitating urine...