麻豆淫院

Many bilaterally symmetrical animals, including humans, possess a continuous digestive tract that extends from the mouth to the anus, allowing food digestion and absorption while expelling waste. This type of gut is a recent evolutionary development in metazoans; its function requires precise control of both the mouth and anus.

In a published in Nature Communications, the authors used sea urchin larvae, which have a simple digestive system, as a model to investigate the specific underlying mechanisms for this regulation.

The group discovered that in sea urchin larvae, the pylorus (entrance) and the anus (exit) open in response to light. Interestingly, each reacts to different wavelengths, so it is exceedingly rare for both to open simultaneously. When one opens, the other remains closed, and vice versa, allowing food to be retained in the digestive tract, for efficient digestion and nutrient absorption, and suggesting that this mechanism likely evolved to ensure optimal digestive efficiency.

The findings suggest that light-regulated control of the digestive tract may have contributed to metazoans' success by helping them efficiently adapt to changes in their external environment.

Further research into how the nervous system regulates the opening and closing of the digestive tract's entrance and exit will provide new insights into how the evolution of digestion is linked to the development of the nervous system and the brain.