Hormonal Communication – Basic Facts

Note

Some of the material in this sheet refers to the human reproductive system

Hormones are chemical messengers produced by various endocrine glands throughout the body. The Endocrine system is the classic system to consider for the concept of Homeostasis as for every hormone released there is usually another to counteract its effects.

Fact - Excess hormones are broken down in the liver.

For this section, it is usual to focus on the hormonal regulation of blood glucose levels, osmoregulation & the reproductive system.

• Blood glucose: the Pancreas secretes Insulin which is involved in glucose uptake by cells. See http://www.revisionworld.com/node/8568 for diabetes information.
• Osmoregulation: the kidneys & hypothalamus secrete hormones to regulate body water balance (ADH)
• Reproductive system: control & management of pregnancy

The Reproductive System & Hormones

Do you have an understanding of:

• The hormonal control of the female sexual cycle?
• The roles of FSH, LH, oestrogen and progesterone?
• The detection and significance of oestrus in a named farm animal?
• the use of HRT (hormone replacement therapy) in treating the symptoms of the menopause, including oestrogen (oral or patch) and progestin;
• cyclic & continual therapy methods for taking HRT.

Activity

Discuss the merits & disadvantages of using HRT to manage the symptoms of the menopause.

Activity

Comment on the ethical issues surrounding the use of technology in manipulating reproduction.

Fact - The endocrine system has a Feed-forward mechanism which means it releases certain hormones prior to their actual need in the body. Insulin is one such hormone.

http://www.unmc.edu/physiology/Mann/mann2.html This website is a bit long but there are some useful charts & graphs to look at – concentrate on those! scroll down about half-way to find feed forward examples.