A hormone is a chemical that is secreted by glands in the endocrine system. Unlike neurotransmitters, they are released directly into the bloodstream. Hormones may act as neurotransmitters and attach to post-synaptic receptor sites. There are several different hormones that appear throughout the course. In this mini-unit on the biology of memory, I will focus on cortisol and adrenaline, the two key hormones of the stress...