The Endocrine System The body’s “slow” chemical communication system. Under “normal” circumstances works in parallel with the parasympathetic NS to sustain our basic processes. In a crisis works to support the actions of the sympathetic NS.

Example... While walking down the street, a man pulls a gun on you… the hormone epinephrine (adrenalin) released into the bloodstream, sustaining the body’s defensive reaction (“fight or flight” response) the endocrine system finishes what your sympathetic NS started, keeping your heart pounding and muscles tense, ready for action

Hormones Hormones are chemicals synthesized by the various endocrine glands and secreted in the bloodstream…have similar structure/function as many neurotransmitters DIFFERENCES BETWEEN… HormonesNeurotransmitters Speed of transmissionSlow (minutes)Fast (seconds) Length of influenceLast longer (wks)Brief duration Method of transmissionBloodstreamNeurons *they are the same thing, just manufactured and located in different parts of the body Neurotransmitters- made in neurons, in the nervous system Hormones- made by gland, in the body and bloodstream

Pituitary Gland “master gland” Attempts to keep all endocrine responses under tight control Pituitary gland is under the control of the hypothalamus…sends out hormone signals to the other endocrine glands

Thyroid & Parathyroid Glands Regulate metabolic, physical growth and development and calcium rate. Adrenal Glands & Pancreas Adrenal glands regulate “fight or flight” response & metabolism. Pancreas regulates level of sugar (glucose) in the blood.

Gonads Regulate bodily development (secondary sex characteristics) and maintain reproductive organs in adults (produce sperm/eggs). produces testosterone produces estrogen & progesterone