Thermoregulation in Extreme Environments

Why ectotherms match environmental temperature?

They lack internal mechanisms to regulate core body temperature.

Why endotherms still fail in extreme cold?

Regulatory mechanisms can only compensate up to a limit; extreme cold → hypothermia.

Define Hypothermia

Core body temperature drops below normal because heat loss exceeds heat production.

Define Hyperthermia

Core body temperature rises above normal because cooling mechanisms can’t keep up.

Define Heat Stroke

Severe hyperthermia where cooling mechanisms fail and body temperature rises uncontrollably.

CoolMitt cooling technology

Cools blood via palms → cooled blood circulates → lowers core body temperature.

Best body regions for heat loss?

Palms, soles, and face (high surface blood flow).

Why muscles feel tired in heat?

Internal temperature rises → protective mechanisms reduce activity to prevent overheating.

Emperor penguin cold adaptations

Huddling, thick insulation, standing on toes to reduce surface area.

African penguin heat adaptation

Red eye spot with blood vessels dissipates heat.

Jack rabbit heat adaptation

Large ears with dense vasculature for heat dissipation.

Arctic rabbit cold adaptation

Thick fur for insulation.

Why climate change threatens thermoregulation?

Temperature changes faster than animals can evolve adaptations.

Steps of thermoregulation

Sense temperature → integrate signal → respond.

Torpor (in cold environments)

Regulated lowering of body temperature via sensory receptors and neuronal signaling.