The Endocrine System
functions Controls body functions and helps maintain homeostasis by using hormones. hormone – chemical messenger made in one cell or tissue that causes a change in another cell or tissue elsewhere in the body. gland – a group of cells that make special chemicals for your body.
organs hormones glands – pituitary – hypothalamus – pineal – thyroid – pancreas – adrenal – ovaries – testes
pineal: Produces hormones that help control sleep, aging, reproduction and body temperature. pituitary and hypothalamus: Produces hormones that help control growth and the release of hormones from other glands. “control center” thyroid: Produces hormones that help control your metabolism (how fast your body uses energy) thymus: Immune system cells develop here adrenals: Produces adrenaline that helps control your heart beat and breathing rate. pancreas: Produces insulin that helps control glucose movement to the cells. ovaries: Produces female reproductive hormones like estrogen. testes: Produces male reproductive hormones like testosterone.
Hormones travel through the bloodstream. They travel from the gland that makes them to every cell in the body. But, only certain cells can respond to certain hormones. – target cell – the cell a certain hormone can affect. vDM
Controlling hormone levels The endocrine glands help keep the body in homeostasis by maintaining the right level of hormones. feedback mechanism – a cycle of events in which information from one step controls or affects another step
negative feedback – effects of a hormone in the body cause the release of that hormone to be turned down.
positive feedback – effects of a hormone in the body cause the release of more of that hormone.
The endocrine system and the nervous system both send messages around the body. – Nervous system sends quick signals. – Endocrine system sends long lasting signals.
The endocrine system controls levels of growth hormone and tells your body when to stop producing it. Too much = gigantism Not enough = pituitary dwarfism