The brain and the spinal cord.

The body’s “slow” chemical communication system; a set of glands that secrete hormones into the bloodstream.

The bundled axons that form neural cables connecting the central nervous system with muscles, glands, and sense organs.

The endocrine system’s most influential gland. Under the influence of the hypothalamus, it regulates growth and controls other endocrine glands. Releases growth hormone, oxytocin (pair bonding, cohesion, social trust).

The information highway. Connects PNS to brain. Governs reflexes.

Hormone that enables contractions associated with birthing, milk flow during nursing, and promotes pair bonding, group cohesion, and social trust.

A simple, automatic response to a sensory stimulus, such as the knee-jerk response.

The chemical messengers that are manufactured by the endocrine glands, travel through the bloodstream, and affect other tissues. Chemically identical to neurotransmitters.

Our brain’s neurons clusters that work in groups. Like cities. They can have short, fast connections.

The pair of endocrine glands that sit just above the kidneys and secrete hormones (epinephrine and norepinephrine) that help arouse the body in times of stress.