Even the best-made machines eventually break down. And the human body, made up of millions of tiny machine-like cells, is no different. Over the years, cells gradually wear from the grueling work of keeping you alive. To restore themselves, they devour their own broken parts. This morning, cell biologist Yoshinori Ohsumi was awarded the Nobel Prize in Physiology or Medicine for identifying the genes and underlying mechanisms that keep our cells in tip-top shape.

Related Content How Nature Inspired the Medicine Nobel Prize Winners to Fight Parasites

The cellular process known as “autophagy” (Greek for “self-eating”) has been known since the 1960s. As far as biological processes go, it’s one of the most important ones. Without being able to tear apart old, broken-down cells for parts, we would age much faster and be more vulnerable to diseases like cancer caused by error-riddled cells running amok.

In the 1950s, scientists discovered that cells of plants and animals are packed with tiny structures called organelles, which are responsible for cellular functions such as generating energy. Researchers noticed, however, that one of these organelles also contained bits and pieces of proteins and structures from the cell itself, "like a garbage dump," write Gina Kolata and Sewell Chan for the New York Times. This trash pile, dubbed the "lysosome," cannibalizes worn out parts of the cell for the raw materials to build anew, according to the Nobel Assembly at Stockholm’s Karolinska Institutet.

Before Ohsumi’s work, however, cellular biologists didn’t have a firm understanding of the inner workings of this process. Scientists knew that cells built little sacs around worn-out proteins and organelles for transport to the lysosome. But beyond this basic process, the cellular recycling remained a mystery, Ariana Eunjung Cha and Anna Fifield report for The Washington Post. By studying the inner workings of small, simple yeast cells, Ohsumi was able to identify the genes that make autophagy possible, how cells determine which parts need replacing and what happens when things go wrong.

"Looking into bodily processes, I found that we have an ongoing renewal process without which living organisms can't survive," Ohsumi tells the Japanese broadcaster NHK. "This recycling process did not receive as much attention as it deserved, but I discovered that we should be paying more attention to this autophagy process."

Ohsumi’s discoveries shed new light on some of the most important processes our cells use to stay healthy. By understanding how autophagy works, scientists hope to better understand the role it plays in aging and disease. Yet despite his accomplishments, Ohsumi remains humble, calling himself “just a basic researcher in yeast,” in an interview with the Canadian newspaper TThe Globe and Mail last year after he received the Canada Gairdner International Award. Perhaps—but some yeast researchers clearly rise to the top more than others.