Endocrine System Hormones Homeostasis AP Biology 2009 2010

Endocrine System Hormones & Homeostasis AP Biology 2009 -2010

Homeostasis u _________________ organism must keep internal conditions stable even if environment changes also called “____________” u example: body temperature ___________________________ w ________________________ Regents Biology ___________________________ w ________________________

Regulation How we maintain homeostasis u _____________ u nerve signals control body functions _________________________ chemical signals control body functions Regents Biology

Nervous System Control Feedback Controlling Body Temperature nerve signals brain sweat high body temperature low brain constricts surface shiver blood vessels Regents Biology nerve signals dilates surface blood vessels

Hormones Why are hormones needed? chemical messages from one body part to cells in other parts of body u communication needed to coordinate whole body u ____________ u Regents Biology growth hormones

Endocrine System Endocrine system releases hormones u __________________________ chemicals cause changes in other parts of body slow, long-lasting response w growth hormones w sex hormones w response hormones w metabolism hormones Regents Biology w and more….

Responding to hormones _________________ u _________________ _________ Regents Biology can’t read signal ______ can’t read signal

Glands ______________ u insulin, glucagon _______ u adrenaline _______ u thyroxine _______ u many hormones: master gland _______ u melatonin estrogen _______ u testosterone Regents Biology

Feedback Maintaining homeostasis hormone 1 lowers body condition gland high specific body condition low raises body condition Regents Biology gland hormone 2

Negative Feedback Response to changed body condition u if body is high or low from normal level u signal tells body to make changes that will bring body back to normal level once body is back to normal level, signal is turned off gland hormone 1 lowers body condition high Regents Biology specific body condition

Endocrine System Control Regulation of Blood Sugar Feedback insulin liver stores sugar body cells take up sugar from blood pancreas high liver blood sugar level (90 mg/100 ml) low triggers hunger Regents Biology liver releases sugar liver pancreas glucagon reduces appetite

Everyone’s doing it, so Ask Questions!! AP Biology 2006 -2007