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.

https://www.youtube.com/watch?v=gjmS4_7kvDM

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