Thermoregulation

Thermoregulation

Overview of Homeostasis

• Homeostatic Systems: maintain an equilibrium (balance)
• Negative Feedback (-): a change triggers the system to counteract this change
• Positive Feedback (+): a change triggers the system to amplify this change
• Thermoregulation: body temperature regulation
• Osmoregulation: solute and water regulation

Types of heat exchange

• Conduction: direct transfer of heat between molecules in direct contact
• Convection: mass movement of warm air or fluid to or from a body/object
• Radiation: emission of electromagnetic waves
• Evaporation: loss of heat energy from the surface of a liquid losing molecules as gas

Ectotherms

• Ectothermic: Do not use metabolism to regulate body temperature
• Most reptiles
• Behavioral thermoregulation: Move between sun and shade to maintain optimal temp
• Requires far less energy to support ectotherm (10%)

Endotherms

• Endothermic: Do use metabolism to regulate body temperature
• Hypothalmus: sensors in brain that regulate internal temperature
• Thermostat of the body
• Countercurrent exchange: the transfer of heat between fluids (blood) moving in opposite directions
• helps reduce heat-loss to cold environment Example: Cold blood heading to the heart is heated by warm blood leaving the heart