Biology Chapter: Homeostasis

Maintaining constant internal conditions within a narrow range, even with external changes. This is crucial for optimal body functioning.

The fluid that surrounds cells, providing them with nutrients and a stable environment.

Maintaining a stable internal environment requires continuous feedback and regulation.

A model of how the body maintains equilibrium. External changes are buffered by internal mechanisms to minimize disruption.

Glucose levels, ion concentrations, and osmotic pressure all need to stay within specific ranges for normal body function.

Most cells have no direct contact with the outside world, so the internal environment becomes their lifeline.

These can be drastic, demanding significant adaptation by the body to maintain balance.

These small changes are the result of constant fine-tuning and regulation by homeostatic mechanisms.

A process that counteracts changes in a controlled variable, bringing it back to its set point.

The level at which a controlled variable is maintained.

The mechanisms that detect and respond to deviations from the set point, bringing the controlled variable back to normal.

The ability to maintain a relatively constant internal body temperature, regardless of external changes.

The ability to change body temperature with the environment, often seen in reptiles and amphibians.

The process of converting glucose into glycogen for storage in the liver.

The process of breaking down glycogen into glucose for use as energy.

Animals that gain heat from their surroundings, such as sunlight or warm water, and rely on behavioral methods like basking or seeking shade to regulate their body temperature.

Animals that generate their own body heat through internal processes, like burning energy from food, to maintain a stable internal temperature.

Ectotherms have a lower metabolic rate, conserve less energy for thermoregulation, and rely on external heat sources for activity.

Endotherms have a high metabolic rate, use significant energy to maintain a constant temp, and can stay active across diverse environments.

Ectothermic animals like fish maintain a body temperature similar to their surroundings, with some exceptions like 'hot' fish.

Ectothermic land animals use behavioral strategies like basking, seeking shade, or wallowing to regulate their body temperature, as air fluctuates more than water.

Some invertebrates, like social insects or flying insects, can regulate their body temperature internally despite being predominantly ectothermic.

Ectotherms rely on external heat sources to maintain a comfortable body temperature. Their thermoregulation is heavily influenced by the environment.

The range of environmental temperatures where an endotherm's metabolic rate is stable and independent of temperature.

The minimal amount of energy an endotherm needs to function while at rest in the thermoneutral zone.

When an animal's internal temperature drops below the thermoneutral zone, it raises its metabolic rate to generate more heat.

When an animal's internal temperature exceeds the thermoneutral zone, it lowers its metabolic rate to dissipate heat.

Narrowing of blood vessels to reduce blood flow to the skin surface, helping conserve heat.

Widening of blood vessels to increase blood flow to the skin surface, facilitating heat loss.

A mechanism where a change in a controlled variable triggers a response that counteracts the change, bringing it back to its set point.

The hypothalamus and skin sensors detect deviations in body temperature.