Final answer:
In cystic fibrosis, poor absorption of fat in the digestive system leads to a change in the appearance of stool, resulting in greasy and bulky stools due to a condition called steatorrhea.
Step-by-step explanation:
In cystic fibrosis, the poor absorption of fat in the digestive system changes the appearance of stool. The impaired digestion of fat leads to a condition called steatorrhea, where large amounts of lipids are excreted in the feces. This results in greasy and bulky stools that may float and have a foul odor.
The reason behind this change is that when fat absorption is impaired, free fatty acids are formed due to hydrolysis. These fatty acids react with free calcium to form insoluble calcium soap, resulting in the loss of calcium in the feces. This, in turn, affects the consistency and appearance of the stool.