AP Bio Unit 4: Day 1 Notes Homestasis, Feedback loops, Thermoregulation

Homeostasis

Maintenance of dynamic internal consistency to provide an optimal internal environment for body functions.

Feedback Loops

Mechanisms that help maintain homeostasis.

Negative feedback

A mechanism that counteracts the original stimulus to bring the body back to the set point, maintaining homeostasis.

Examples of Negative Feedback

1. Blood pressure regulation

2. Body temperature regulation

3. Ion concentration regulation

4. H2O concentration regulation.

Positive feedback

Amplifies the original stimulus but does not maintain homeostasis; important in specific biological processes.

Examples of Positive Feedback

1. Clotting factors
2. Childbirth
3. Milk secretion/lactation.

Thermoregulation

The ways in which heat is exchanged with the environment.

Metabolism in Thermoregulation

Chemical reactions that generate heat as a byproduct, relevant for maintaining body temperature.

Evaporation (Cooling Mechanism)

Sweating cools the body by taking heat away.

Convection (Cooling Mechanism)

Panting moves air to facilitate heat transfer.

Radiation (Cooling Mechanism)

Emission of energy, like from the sun.

Conduction (Cooling Mechanism)

Heat transference between surfaces.

Endotherms

Warm-blooded organisms that maintain body temperature using metabolism, regardless of external temperatures.

Ectotherms

Cold-blooded organisms whose body temperature changes with the environment.

Line A (Endotherm)

In lower temperatures, the oxygen consumption rate is higher; in higher temperatures, it is lower as body temperature is maintained.

Line B (Ectotherm)

Internal temperatures change with external temperatures, requiring behavioral adaptations to maintain ideal temperatures.