Objectives

• Explain what is meant by the term endocrine gland.

• Describe the cellular structure of an islet of Langerhans from the pancreas.

• Outline the role of the pancreas as an endocrine gland.

http://www-medlib.med.utah.edu/WebPath/ENDOHTML/ENDO032.html

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Pancreas

• Exocrine Gland: a gland that secretes externally through a duct

• Endocrine Gland: a gland that secretes hormones into the bloodstream.

Pancreas

• The pancreas has an exocrine portion that secretes digestive enzymes that are carried through a duct to the duodenum. The endocrine portion consists of the pancreatic islets, which secrete glucagons and insulin.

Objectives

• Explain how the blood glucose concentration is regulated by negative feedback control mechanisms, with reference to insulin and glucagon.

• Discuss the importance of homeostasis in mammals, and explain the principles of homeostasis in terms of receptors, effectors and negative feedback.

                                                                                                                                                                                                          

Hormones

• Most hormones circulate in blood, coming into contact with essentially all cells. However, a given hormone usually affects only a limited number of cells, which are called target cells. A target cell responds to a hormone because it bears receptors for the hormone.

• The effector is usually an organ.

Objectives

• Explain the advantages of treating diabetics with human insulin produced by genetic engineering.