Importance of the Endocrine System

8.1

Hormones

• chemical regulators produced by cells in one part of the body that affect cells in another part of the body

• endocrine hormones are secreted by endocrine glands directly into the blood

Endocrine System(Image on next slide from: http://scienceblogs.com/clock/2006/06/bio101_lecture_6_physiology_re.php)

Endocrine vs. Nervous

• both systems integrate and control organs and tissues

• nervous system helps body to adjust quickly to changes

• endocrine system maintains control over longer periods of time

Types of hormones

• nontarget hormones affect many cells throughout the body, e.g., growth hormone

• target hormones affect specific cells or tissues, e.g., ADH

Steroid vs. Protein Hormones

• differ in their chemical structure and their action

• steroid hormones are made from cholesterol, e.g., testosterone, estrogen

• protein hormones have chains of amino acids and are water-soluble, e.g., insulin

Steroid Hormones(Image from: http://nekaeportfolio.blogspot.com/2011/02/identifying-classes-of-hormones.html)

Animation…

• Narrated animation of steroid hormone action:

• http://highered.mcgraw-hill.com/olcweb/cgi/pluginpop.cgi?it=swf::535::535::/sites/dl/free/0072437316/120109/bio46.swf::Mechanism%20of%20Steroid%20Hormone%20Action

Protein Hormones(Image from: http://schoolworkhelper.net/2010/07/the-endocrine-system-function-and-structure/)

Animation…

• Narrated animation of protein hormones:

• http://highered.mcgraw-hill.com/sites/0072943696/student_view0/chapter10/animation__second_messenger__camp.html

The Master Gland

Pituitary Gland(Image on previous slide from: http://www.bing.com/health/article/mayo-126596/PraderWilli-syndrome?

q=prader-willi+syndrome&qpvt=prader+willi+syndrome)

• secretes hormones that control other endocrine glands

• produces and stores hormones, and is under the nervous control of the hypothalamus

Pituitary Gland(Image from: http://www.ualberta.ca/~somji/pituitary.html)

Pituitary Gland

• posterior lobe stores and releases hormones produced by the hypothalamus (ADH and oxytocin)

• anterior lobe produces and stores and releases hormones (growth hormone, TSH, ACTH, prolactin, MSH, FSH and LH)

Releasing Factors

• produced in hypothalamus

• control the release of hormones from the anterior pituitary

• dopamine inhibits secretion of prolactin

• somatostatin inhibits secretion of somatotropin (growth hormone)