3.6.4.1 Principles of homeostasis and negative feedback Flashcards
What is homeostasis in mammals?
Homeostasis in mammals involves physiological control systems that maintain the internal environment within restricted limits.
Why is it important to maintain a stable core temperature in mammals?
A stable core temperature is crucial because enzymes have an optimum temperature. Deviations reduce enzyme activity and may cause denaturation affecting metabolic reactions.
Why is it important to maintain a stable blood pH?
A stable blood pH is necessary to maintain the tertiary structure of enzymes. Extreme pH changes disrupt hydrogen and ionic bonds leading to enzyme denaturation and reduced efficiency.
What are the consequences of unstable blood glucose concentration for respiration?
Unstable blood glucose concentration affects the availability of glucose as a respiratory substrate impacting ATP production through respiration.
How does blood glucose concentration affect the water potential of blood?
High blood glucose lowers the water potential of blood leading to osmotic movement of water out of cells causing cellular dehydration.
What is negative feedback in homeostasis?
Negative feedback restores systems to their original level by reversing a change in a physiological condition.
Why is it beneficial for homeostasis to have separate mechanisms involving negative feedback?
Separate mechanisms for negative feedback control departures in different directions from the original state providing a greater degree of control.
What is an example of negative feedback in homeostasis?
Regulation of blood glucose concentration: When blood glucose levels rise insulin is released to lower it; when levels fall glucagon is released to increase it.
What is an example of positive feedback in biological systems?
During childbirth the release of oxytocin increases uterine contractions which further stimulates the release of more oxytocin.
How can you interpret information about positive feedback mechanisms?
Positive feedback amplifies a change away from the original state rather than reversing it often driving processes to completion.
How can you interpret information about negative feedback mechanisms?
Negative feedback counters changes by reversing deviations maintaining conditions within a set range or returning them to the original level.
