Page 334 - Biology_F5

Chapter
Seven

Regulation
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(Homeostasis)

Introduction

The internal environment of multi-cellular organisms is made up of tissue fluids whose
conditions, such as pH, temperature, pressure, glucose concentration and salt contents,
are always kept at a relatively constant level regardless of the fluctuations of the external
environments. The ability to maintain a constant internal body environment enables
an organism to survive in a variety of habitats. In this chapter, you will learn about
body regulation in mammals which include feedback mechanisms, urine formation,
and osmoregulation. The competences developed will enable you to understand how
organisms adapt, and survive in different environments.

in mammals. He described variation in
Think glucose concentration in the blood. His
study revealed that the concentration of
The mammalian body incapable of glucose in the blood of mammals remained
regulating its different internal condition
relatively constant regardless of variation
7.1 The concept of regulation in diet. For example, dogs that were well
fed with food rich in meat or sugar had
Task 7.1 similar glucose concentration in the blood
Search from the internet sources, as starving dogs. From these results, he
the simulations on homeostasis of
temperature and blood sugar, then concluded that mammals must have a
explain what you have observed. control mechanism that keeps their internal
environment constant, despite the changes
The importance of regulation (homeostasis) in external environment. This tendency
in animals was first pointed out by the French enables them to exploit a wide variety of
physiologist Claude Bernard in 1857. In one habitats. For example, in human beings,
of his researches, he used dogs to study the the internal mechanism maintains constant
importance of constant internal environment body temperature of about 37 C despite a
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