Cell homeostasis is the tendency of a cell to continue to function properly and efficiently by interacting with both inner and outer stimuli. Ideal cell homeostasis would require the cell to continue to maintain harmony within itself, despite constant changes in its environment. Most of the time, cells are able to do this, though no cell function is absolutely perfect. If that were true, living things would not have genetic deformities, illnesses, or nutrient deficiencies. Any organism in relatively good health, though, is generally defined as being able to maintain excellent cell homeostasis.
A very large part of cell homeostasis involves maintaining a healthy environment inside the cell. This requires the cell to perform a wide range of functions correctly and efficiently. The term homeostasis literally translated means “staying the same.” The temperature, metabolic rate, amount of waste, and energy production inside a cell must remain the same for the cell to stay healthy. Under ideal circumstances, a cell will receive exactly the right amount of nutrients each day, process those nutrients quickly, expel the waste, and remain at a temperature conducive to all of these processes.
Unfortunately, very few organisms live in a space that allows them to function under ideal circumstances all the time, so cells must adapt. For instance, if cells aren’t getting enough of a certain vitamin, the organism will start to crave things that contain that vitamin. A human with a vitamin D deficiency may crave dairy items, desire the warmth of the sun, or eat a salad filled with kale and other vitamin-rich greens. Animals may also seek out nutrient-rich items in a similar fashion, looking instinctively for things that they need to maintain cell homeostasis.
If the nutrient deficiency is not met, the organism generally pulls its energy toward maintaining vital systems, redirecting nutrients from non-vital places. For instance, a plant attempting to maintain cell homeostasis in its stem and root system may pull energy out of the leaves. This often shows as leaf discoloration or wilt. When the nutrient deficiency is addressed, the plant will begin to renew itself by pushing energy back into the rest of the organism.
A similar process happens in ill humans and animals. A person who is sick with a cold often experiences coughing, sneezing, headache, and congestion. These symptoms are responses to something in the body that shouldn’t be there. The body is trying to maintain cell homeostasis by fighting off the virus attempting to replicate inside the cells. When the virus is gone, cell function should return to normal.