What is cortisol known for?

Cortisol is a steroid hormone produced by the adrenal glands that plays a crucial role in regulating various bodily functions, particularly in response to stress. It is well-known for its ability to help manage how the body uses carbohydrates, fats, and proteins, effectively regulating metabolism. Additionally, cortisol contributes to the body's response to stress by increasing blood sugar levels, enhancing brain use of glucose, and curbing non-essential functions in a fight-or-flight situation.

In contrast, the other options refer to processes or substances that are not related to cortisol's primary functions. For example, neurotransmitters are chemical messengers in the brain, blood flow to the brain involves different regulatory mechanisms, and sleep-wake cycles are primarily controlled by hormones such as melatonin rather than cortisol itself, although cortisol levels can fluctuate in a daily rhythm that relates to sleep patterns. Thus, the role of cortisol in regulating metabolism and stress responses is clearly significant and well-documented in the field of biopsychology.