Journal: What is the function of the endocrine system? After you complete this journal, hand in your journals. You should have at least 15 entries. Series of organs and glands that secrete hormones into your bloodstream What does the Endocrine System control? 1. Growth & development 2. Reproduction 3. Reducing body stress 4. Maintaining water, electrolyte and nutrient balance 5. Regulating cellular metabolism and energy balance 6.Maintain homeostasis Major Endocrine Glands Hypothalamus & Pituitary Glands Thyroid & Parathyroid Gland Capsule Adrenal Glands Pancreas Chemical messengers released by endocrine glands that are released into the blood stream and travel all over your body Cause a widespread response Chemical Messenger Comparison Neurotransmitters Hormones Chemical Messenger Chemical Messenger Released at chemical synapse Intended for close target Released into bloodstream Effect happens quickly Effect takes time Effect wears off quickly Effect lasts longer Affects single cell Affects many cells Travels to distant targets Hormones bind to receptors on the outside or inside of target cells • If the receptor is on the outside… It changes cell membrane permeability It changes enzyme activity inside the cell • If it binds to receptors inside the cell… Its called a steroid Interact directly with the cell’s DNA to change cell activity Most endocrine organs are active all the time, but the amount of hormone produced changes Homeostasis including the amount of hormones produced is regulated through positive and negative feedback loops Neural Control • Hormone levels controlled by the nervous system Ex: Adrenal gland secretes hormones to prolong sympathetic response Hormonal Control • Glands are arranged in a hierarchy and each regulate the gland below them in the chain Ex: Hypothalamus controls the pituitary gland which controls the adrenal gland which produces a hormone called cortisol, which allows humans to deal with stress Humoral Control • Hormone levels controlled by body fluids Ex: Pancreas secretes insulin in response to rising blood sugar