5.3 Homeostasis Flashcards
What is homeostasis ?
The body maintaining a dynamic equilibrium , with small fluctuations over a narrow range of conditions.
What are some factors affected by homeostasis ?
Blood pH, blood glucose concentration levels, urea concentration, temperature, water content.
What are 2 factors that are vital for homeostasis ?
Receptor and effectors as they detect and respond to change.
What is a negative feedback system ?
When a small change in one direction is detected by sensory receptors, effectors work to reverse the change. They work to reverse the initial stimulus.
What occurs in a negative feedback system when a increase is directed ?
An increase is detected, causing a reduction in levels to return back to ideal conditions.
What occurs in a negative feedback system when a decrease is directed ?
A decrease is detected, causing an increase in levels to return back to ideal conditions.
What is a positive feedback system ?
A change in conditions caused a reinforcement of the change.
Eg, blood clotting, contractions, depolarisation.
What is thermoregulation ?
Maintenance of a relatively constant core body temperature to maintain optimum enzyme activity.
What are ectotherms ?
Most animals are ectotherms and they use their surroundings to warm up their body temperature.
What are endotherms ?
Mammals and birds are endotherms. They rely on metabolic processes to warm up.
What are behavioural responses ?
Changing behaviour to control temperature of the body to warm up or cool down.
What are physiological responses ?
Body features that help to warm up or cool down the body. Eg, dark fur.
Why don’t ectotherms thermoregulate ?
They have a high heat capacity of water and many live in water.
Why do ectotherms require less food ?
They require les food due to requiring less energy to regulate temperature.
