Psychology: Hormones and Neurotransmitters

Hormones and Behavior

• Hormones are chemicals that affect behavior, but unlike neurotransmitters, they are secreted by glands in the endocrine system, not released by neurons.
• Hormones are released directly into the bloodstream, which means they take longer to produce changes in behavior than neurotransmitters, but their effects can last longer.

Types of Hormones

• Adrenaline (Epinephrine): secreted by the adrenal glands, responsible for arousal and the "fight or flight" response, and plays a role in emotional memory formation.
• Cortisol: secreted by the adrenal glands, helps control blood sugar levels, regulate metabolism, reduce inflammation, and assist with memory formation.
• Melatonin: secreted by the pineal gland, signals relaxation and lower body temperature, helping with restful sleep.
• Neuropeptide Y (NPY): produced by the hypothalamus, acts as a neurotransmitter in the brain, stimulates food intake, reduces anxiety and stress, reduces pain perception, and affects circadian rhythm.
• Oxytocin: produced by the hypothalamus and secreted by the pituitary gland, acts as a neurotransmitter, plays a role in mother-child attachment, and social bonding and trust between people.
• Testosterone: produced by the testes, plays a facilitative role in aggressive behavior, higher levels of testosterone result in higher levels of aggression.

Adrenaline and the Fight or Flight Response

• Adrenaline activates the fight-or-flight response, a hormone cascade where hormones trigger more hormones.
• The release of adrenaline is part of the hypothalamic-pituitary-adrenal axis (HPA axis).
• When a stimulus threatens us, the hypothalamus responds by activating the pituitary gland, which releases a hormone that activates the adrenal glands, releasing cortisol and adrenaline into the bloodstream.

Learn about the difference between hormones and neurotransmitters, their release and function in the body, and their impact on behavior.