Recently I've been playing volleyball with some friends. I think that during our games, I experience anxiety and "stressful" moments whenever there are plays that require agile movements. The feeling of anxiousness increases when the scores reach matchpoints, where every move must contribute positively to the team and not commit service, receive, or spike errors.
After studying the endocrine system, I have come to realize that the adrenal gland contributes to my response during such "stressful" moments when I am playing volleyball. The adrenal medulla secretes adrenaline which dilates the air passages that provide muscles with much oxygen. In times of "critical" plays of volleyball, I often feel that I have more heat in my body and I can feel that I have better overall control and force with the ball. I have learned that adrenaline, also called epinephrine, is part of the fight-or-flight response of the body.
Going beyond our lecture, I also learned that the pituitary gland and hypothalamus synthesize endorphins. Endorphins provide a short-lasting euphoric state after intense activity. That's why I have realized that after jumping strenuously and sweating profusely, the happiness I feel is influenced by the endorphins in my body.