Lecture notes chapter 40

Can transfer heat between objects that are not in

Info iconThis preview shows page 1. Sign up to view the full content.

View Full Document Right Arrow Icon
This is the end of the preview. Sign up to access the rest of the document.

Unformatted text preview: in environments with stable temperatures Are endotherms always homeotherms? No, some animals will enter inactive states in which they maintain lower body temperatures Hummingbirds decrease temperature set point at night – torpor Balancing heat loss and gain Four physical processes allow for the exchange of heat between an organism an its environment RadiaBon: Emission of electromagneCc waves. Can transfer heat between objects that are not in direct contact ConvecBon: Transfer of heat by movement of air or liquid past a surface blood, wind EvaporaBon: Removal of heat from the surface of a liquid that is loosing some of its molecules as gas ConducBon: Direct transfer of heat between molecules of objects in direct contact with each other Note: heat is transferred from an object of high temperature to one of lower temperature Several mechanisms are involved in thermoregula2on Several of these mechanisms involve the Integumentary System: Skin, Hair, and nails Outer layer of skin Inner layer of skin Raised Feathers InsulaBon: Hair, feathers, layers of fat – major thermoregulatory adapCon in birds and mammals Marine mammals that live in near freezing water have a thick layer of fat called blubber * heat transfer in water occurs 50 to 100x faster than heat transfer in air Blubber allows marine mammals to maintain a body temperature between 36 and 40 °C without acquiring more food energy than land animals of similar size Circulatory AdapBon: VasodilaBon: increase the diameter of blood vessels found near the body surface (superficial) Example: An increase is the diameter of blood vessels size will increases the transfer of body heat to the environment that occurs by radiaCon, conducCon and convecCon. VasoconstricBon: decrease in the diameter of the superficial blood vessels Example: A decreases in the diameter of blood vessels will decrease the transfer of heat from the environment to the body that occurs by radiaCon, conducCon and convecCon Countercurrent Heat Exchangers: involves the anCparallel arrangement of blood vessels Arteries transfer heat to veins Heat exchange occurs along the enCre length of the exchanger As blo...
View Full Document

Ask a homework question - tutors are online