Thermoregulation PDF

Thermoregulation : Keeping Cool and Staying Warm This Photo by Unknown Author is licensed under CC BY  The process by which organisms maintain their internal body temperature within a certain range Crucial for su...

Thermoregulation : Keeping Cool and Staying Warm This Photo by Unknown Author is licensed under CC BY  The process by which organisms maintain their internal body temperature within a certain range Crucial for survival and optimal functioning of bodily What is processes Involves various physiological and behavioral Thermoregulation? mechanisms Helps organisms adapt to different environmental conditions Types of Thermoregulators Homeotherms/Endotherms: Maintain a constant internal body temperature. They typically generate heat through metabolic processes Example: Humans, most mammals, and birds Poikilotherms/Ectotherms: Internal body temperature varies with the environment Example: Most fish, amphibians, and reptiles Thermoregulation in Humans Humans are homeothermic endotherms Normal body temperature range: (36.5°C - 37.5°C) Controlled by the hypothalamus in the brain Involves both heat production and heat loss mechanisms Heat Production in Humans Metabolic processes: Cellular respiration generates heat Muscle contractions: Shivering increases heat production Hormonal regulation: Thyroid hormones increase metabolic rate Brown fat activation: Generates heat in infants and some adults  Heat Loss in Humans Radiation: Heat transfer to cooler surroundings Conduction: Direct heat transfer through physical contact Convection: Heat loss through air or water currents Evaporation: Cooling through sweat and respiratory moisture Thermoregulation Mechanisms in Humans Vasodilation: Blood vessels expand to increase heat loss Vasoconstriction: Blood vessels constrict to conserve heat Sweating: Evaporative cooling through skin Piloerection: Goosebumps trap air for insulation Behavioral changes: Seeking shade, changing clothing, etc.  Thermoregulation in Other Animals Diverse strategies across species Adaptations depend on habitat, size, and metabolic needs Some animals use a combination of methods Ectotherm Strategies Basking: Absorbing heat from the sun Seeking shade or water to cool down Thi s Photo by Unknown Author i s l icensed under CC BY-NC-ND Color changes: Darker colors absorb more heat Behavioral adaptations: Burrowing, changing activity patterns  Endotherm Strategies Fur or feathers for insulation Countercurrent heat exchange in blood vessels Panting or gular fluttering for cooling Huddling for warmth in social animals Specialized Thermoregulation: Torpor Definition: A state of decreased physiological activity Characterized by reduced body temperature Thi s Photo by Unknown Author i s l icensed under CC BY-SA and metabolic rate Usually lasts for short periods (hours or days) Examples: Hummingbirds, bats, and some small mammals Thi s Photo by Unknown Author i s l icensed under CC BY-NC-ND  Specialized Thermoregulation: Hibernation Extended period of torpor lasting weeks or months Thi s Photo by Unknown Author i s l icensed under CC BY-NC Significant drop in body temperature, heart rate, and breathing Occurs during winter in temperate or polar regions Examples: Bears, ground squirrels, and some bats Thi s Photo by Unknown Author i s l icensed under CC BY-SA Specialized Thermoregulation: Estivation Similar to hibernation but occurs during hot, dry periods Involves inactivity and lowered metabolic rate Helps conserve water and energy Examples: Lungfish, desert tortoises, and some frogs Thi s Photo by Unknown Author i s l icensed under CC BY-NC