The Endocrine SystemChapter 25 Section 3

Objectives:•Explain why the endocrine system is

important to the body

• Identify the glands of the endocrine system, and describe what their hormones do

•Describe how feedback mechanisms stop and start hormone release

•Name 2 hormone imbalances

Hormones as Chemical Messengers:•Purpose: to control body functions by using

chemicals that are made by the endocrine glands

•Gland: a group of cells that make special chemicals for your body

•Hormone: a chemical messenger made in one cell or tissue that causes change in another cell or tissue in another part of the body

The Endocrine System:

http://www.innatehealthsolutions.com/images/hormones1.jpg

The Endocrine Glands & Their Functions:1. Pituitary2. Thyroid3. Parathyroid4. Thymus5. Adrenal6. Pancreas7. Ovaries8. Testes

The Pituitary Gland:•Location: The brain

•Function: secretes hormones that affect other glands and organs▫Stimulates skeletal growth▫Helps the thyroid gland work properly▫Regulates the amount of water in your

blood▫Stimulates the birth process in women

http://www.tvscoop.tv/pituitary_gland.gif

The Thyroid Gland:•Location: the neck

•Function: Increase the rate at which you use energy▫Very important during childhood and infancy▫Controls the secretion of growth hormones

for normal body growth▫Control the development of the CNS▫Control metabolism

http://www.abc.net.au/health/library/img/thyroid_gland_diag.gif

The Parathyroid Gland:

•Location: behind the thyroid gland

•Function: regulated calcium levels in the blood

http://www.clarian.org/ADAM/doc/graphics/images/en/8890.jpg

The Thymus Gland:

•Location: behind the breastbone

•Function: important to the immune system▫Killer T cells grow and mature here▫Helps protect the body against pathogens

http://www.dana.org/uploadedImages/Images/Spotlight_Images/DanaGuide_CH16C52_P532_spot.jpg

The Adrenal Gland:•Location: on the kidneys

•Function: help the body respond to danger▫Release epinephrine (adrenaline) – increases HR

and respiration; “fight or flight” response

http://www.web-books.com/eLibrary/Medicine/Physiology/Endocrine/adrenal_gland.jpg

The Pancreas:•Location: deep in the abdomen

•Function: regulates blood glucose levels▫Insulin ▫Glucagon

http://www.nlm.nih.gov/medlineplus/ency/images/ency/fullsize/8883.jpg

The Ovaries:

•Location: in the female pelvis

•Function: produce hormones needed for reproduction▫Estrogen ▫Progesterone

http://graphics8.nytimes.com/images/2007/08/01/health/adam/19263.jpg

The Testes:

•Location: male pelvic region

•Function: produce hormones needed for reproduction▫Testosterone

http://www.soc.ucsb.edu/sexinfo/images/10-07-testes.jpg

Controlling Endocrine Glands:

•Similar to the feedback mechanism in the nervous system

•Ex: Pancreas▫Has specialize cells that make 2 hormones:

insulin & glucagon▫Insulin lower blood glucose levels – tells

liver to convert glucose into glycogen▫Glucagon tells liver to convert glycogen

into glucose to release into the blood

Pancreatic Hormones:

http://biomed.brown.edu/Courses/BI108/BI108_2002_Groups/pancstems/stemcell/pancreas.gif

Hormone Imbalances:

•Sometimes an endocrine gland makes too much or not enough of a hormone

•Diabetes Mellitus: when the pancreas does not make enough insulin

•Imbalance in the Pituitary Gland: not enough growth hormone

Diabetes Mellitus:

http://www.ghsa.net/files/images/Checking_Blood_Sugar.jpg http://www.ghsa.net/files/images/Insulin_Pump.jpg