What are the roles of CRF, ACTH, and Cortisol during stress?

When a person is stressed, CRF, or Corticotropin Releasing Factor is released by the hypothalamus and it goes to the pituitary gland, right below the hypothalamus. CRF causes the pituitary gland to secrete ACTH (adrenocorticotropic hormone) into the blood stream. When the ACTH reaches the adrenal glands (above the kidneys), it causes them to secrete cortisol, the "stress hormone." Cortisol increases blood pressure and blood sugar levels. It also increases the body's immune response for a short while.