Objectives:

Without using any resources, at the end of the Introduction to Physiology section you should be able to complete the following learning objectives:

1. Define the terms homeothermic and homeostasis.

2. Define the terms vasoconstriction and vasodilation, and indicate how heat flow from the core through the physiological shell is impacted by these processes.

3. List the three thermal insulators that comprise the physiological shell of poultry, and describe how each of the thermal insulators is able to contribute to controlling heat flow.

4. Explain how total heat production and heat production per unit body weight changes as body weight increases.

5. List the body temperatures of young (> three weeks) and older chickens, and explain why supplemental heat must be available for young birds.

6. List the four components of the thermal environment to which poultry are exposed.

7. Define the two major categories of thermoregulatory mechanisms.

8. Describe each of the temperature zones to which poultry may be exposed. For each zone, list the thermoregulatory mechanism(s) that may be used, including specific examples.

9. Describe how the range of temperatures in the thermoneutral zone changes as birds age.

10. Provide an explanation for spiraling hyperthermia that occurs in the intolerably hot zone, and explain the contribution of the Van't Hoff effect.

11. Provide a general description of sensible and insensible heat loss.

12. Define radiation, conduction and convection (as they relate to sensible heat loss), and give at least three real-world examples of heat transfer by each mechanism. Include references to vasodilation and vasoconstriction in your response.

13. Describe how insensible heat loss is affected by relative humidity.

14. Describe how the proportion of heat lost by insensible and sensible mechanisms is impacted by environmental temperature.

15. Explain why water is such a critical component of the body for temperature regulation.

16. Describe how panting can lead to dehydration, and may eventually lead to wet litter in a poultry house.

17. Describe how the following are affected by environmental temperature: feed intake, water intake, percentage and amount of water lost in the respiration vs. feces.

18. Describe how body size impacts the percentage of moisture lost in the feces vs. respiration.