14 - homeostasis and thermal regulation

14 - homeostasis and thermal regulation - BIOLOGY 325H...

Info iconThis preview shows pages 1–2. Sign up to view the full content.

View Full Document Right Arrow Icon
BIOLOGY 325H Homeostasis and Thermal Regulation 2/18/08 One of the central themes of biology is homeostasis, a general name for those physiological mechanisms by which an organism can maintain an internal environment that is beneficial for the survival and function of its tissues. As we have already discussed, multicellular animals use different organs to exchange chemical compounds (O 2 , CO 2 , nutrients, and metabolic waste products) with their environment and large animals have evolved active means of mixing body fluids to insure that all cells within the body are exposed to roughly the same chemical milieu. This is one example of homeostasis. Homeostasis also refers to the means by which an organism protects its own internal environment from unpredictable fluctuations in the external environment. Today we will focus on thermal homeostasis, i.e. the ways in which some - but not all - animal species actively regulate their body temperature to maintain internal conditions that are optimal for survival. Learning goals 1. What is the primary source of heat in an animal’s body? What is the ultimate destination of that heat? 2. What is meant by the phrase 'negative feedback', and why is it critical for homeostasis? You should be able to describe in general terms the three necessary components of a control system that can produce homeostasis by negative feedback. Where is the ‘thermostat’ located in humans? 3. In mammals, what two physiological mechanisms are used to generate extra body heat (= thermogenesis) in response to low external temperatures? Do birds employ one or both of these mechanisms? 4. Animals show a number of adaptations that help them to retain body heat, i.e. retard its loss to the environment. What organ is primarily responsible for heat loss? How have mammals adapted their anatomy to insulate against heat loss? Why do marine mammals need greater heat retention, and how do they accomplish it? How have birds adapted the anatomy of their body surface to insulate against heat loss? 5. How does your body change the pattern of blood flow in order to conserve or lose heat?
Background image of page 1

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Image of page 2
This is the end of the preview. Sign up to access the rest of the document.

This note was uploaded on 05/14/2008 for the course BIO 325H taught by Professor Staff during the Spring '08 term at University of Texas at Austin.

Page1 / 8

14 - homeostasis and thermal regulation - BIOLOGY 325H...

This preview shows document pages 1 - 2. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online