Environment: Temperature Control

Factors Affecting Body Temperature

Body temperature in organisms is influenced by external environmental conditions, metabolic rate and activity levels.
In humans, the normal body temperature is approximately 37 degrees Celsius. Significant deviations could result in health complications.
Variations in body temperature are detected by the hypothalamus in the brain, which serves as the body’s thermostat.

Mechanisms of Heat Production

Metabolism is the main source of body heat. Heat is generated through biochemical reactions inside cells, including respiration.
Skeletal muscles also generate heat, both through constant small contractions (shivering), and through higher intensity contraction during exercise.
Brown adipose tissue, or brown fat, has a unique metabolic function in heat production, a process called thermogenesis.

Mechanisms of Heat Loss

Heat loss occurs primarily through the skin, either through radiation (emitting warming infrared rays), conduction (direct heat transfer to a cooler item in contact), or convection (heat transfer to air which then moves away).
Evaporation of sweat from the skin surface also helps in cooling the body.
Respiration, especially panting, can also result in significant heat loss.
Vasoconstriction and vasodilation affect heat loss. Vasoconstriction reduces blood flow to the skin, conserving heat, while vasodilation increases it, promoting heat loss.

Regulatory Processes

Organisms use negative feedback mechanisms to maintain a steady body temperature.
In response to too high internal temperatures, the body will initiate cooling procedures. This includes sweating, vasodilation, and sometimes increasing breathing rate.
In response to too low temperatures, the body will work to conserve or generate heat. This involves reducing sweat production, vasoconstriction, and shivering.
Adaptations such as fur in mammals, blubber in marine animals, and feathers in birds provide insulation to conserve body heat.

In revising environment and temperature control, ensure to understand these mechanisms and how they interact to regulate body temperature. This is crucial for an organism’s survival, as maintaining body temperature within a normal range facilitates optimal biological function.