Thermoregulation
Overview
The human body uses a series of feedback systems to maintain homeostasis. These systems are constantly monitoring the internal and external conditions to see if it is deviating from the set point. If conditions are outside of optimal functioning range, the body initiates mechanisms to bring itself back towards the optimal range. This section explores feedback mechanisms that regulate the internal environment. All organisms exchange thermal energy with their environment through four mechanisms: 1. Conduction: the flow of thermal energy between molecules that are in direct contact 2. Convection: the transfer of thermal energy within a fluid (liquid or gas) 3. Radiation: the transfer of thermal energy in the form of electromagnetic radiation, can be lost and gained 4. Evaporation: water on the surface of the skin evaporating, absorbing thermal energy from the skin and causing it to cool |
Important Concepts
All animals can be categorized into two groups based on the stability of their body temperature:
1. Homeotherms:
2. Poikilotherms:
Both types of animals use different strategies to regulate their body temperature, resulting in different responses to changes in the external temperature. As a result, all animals can also be categorized into two types based on the mechanism they use to regulate their body temperature:
1. Endotherms:
2. Ectotherms:
1. Homeotherms:
- animals that maintain a stable body temperature regardless of the temperature of the external environment
- examples: birds, mammals
2. Poikilotherms:
- animals whose body temperature varies with, and often matches, the temperature of the external environment
- examples: fish, amphibians, reptiles, most invertebrates
Both types of animals use different strategies to regulate their body temperature, resulting in different responses to changes in the external temperature. As a result, all animals can also be categorized into two types based on the mechanism they use to regulate their body temperature:
1. Endotherms:
- Animals that maintain its body temperature by internal mechanisms
- examples: birds, mammals
2. Ectotherms:
- Animals that maintain its body temperature by absorbing thermal energy from the environment
- Examples: invertebrates, fish, amphibians, reptiles