Slide 1

Student SampleChristopher Duncan1What is Homeostasis? homeo = same; stasis = standingHomeostasis is the term we use to describe the constant state of the internal environment.Homeostasis is a state of balance in the body.The processes and activities that help to maintain homeostasis are referred to as homeostatic mechanisms

Neural and endocrine control

Sensory receptors detect change in a monitored variable The body must have good internal communication, using the endocrine and nervous systems, to maintain homeostasis.

Nervous system and/or endocrine system responds

Feedback Loop

All homeostatic mechanisms use negative feedback to maintain a constant value (called the set point).

Negative feedback never maintains perfectly, but constantly fluctuates about the set point. An efficient homeostatic system minimizes the size of the fluctuations.

Thermoregulation(click on the tabs below)What happens when the body becomes imbalanced?

Variations in hormone concentration and target cell sensitivity have noticeable effects on the body

Hypo secretion inadequate hormone releasetumor or lesion destroys glandhead trauma affects pituitary glands ability to secrete ADHdiabetes insipidus = chronic polyuria

Hyper secretion excessive hormone releasetumors or autoimmune disordertoxic goiter (graves disease) antibodies mimic effect of TSH on the thyroid

The Bodys Stress Reaction

Stress =

Hormone Secretion=

Unbalanced SystemWhat are the major glands and hormones involved in Homeostasis?

Hypothalamus (Master Gland)Thyrotropin-releasing hormoneGrowth HormoneGonad releasing hormoneCorticotropin-releasing hormoneMajor Gland and HormonesPancreasInsulinGlucagonSomatostatinAmylin

Major Glands and HormonesThyroid GlandThyroxineTriiodothyronineCalcitonin

SummaryHomeostasis is the process by which the human body maintains comparative steadiness of internal conditions. Homeostasis is retained through negative feedback loops.Homeostasis is achieved through neural and endocrine processes.

Works CitedTeachers' Domain, Blood Flow and Thermoregulation, published August 9, 2007, retrieved on March 15, 2009,http://www.teachersdomain.org/resource/lsps07.sci.life.reg.heatexchange/A.D.A.M. Inc., Multimedia Encyclopedia, 1997-2008, retrieved on March 14, 2009-03-15, http://www.adam.com/multimediaencyclopedia.aspxJohnson, Michael. Human Biology: Concepts and Current Issues (4th Edition) (The Human Biology Place Series). San Francisco: Benjamin Cummings, 2007. "Physiological Homeostasis." Biology Online. 1 Jan. 2000. 13 Mar. 2009. http://www.biology-online.org/4/1_physiological_homeostasis.htm