Principles of Homeostasis (16) Flashcards
What is meant by homeostasis?
maintaining a constant internal environment
Why must core temperature remain stable?
to maintain stable rate of enzyme-controlled reactions and prevent damage to membranes
What happens if core temperature is too low?
enzyme and substrate molecules will have insufficient kinetic energy
What happens if core temperature is too high?
enzymes become denatured
Why must blood pH remain stable?
to maintain stable rate of enzyme-controlled reactions and optimum conditions for other proteins
What happens if pH is too low (acidic)?
hydrogen ions will interact with H-bonds and ionic bonds in enzymes tertiary structure, causing these bonds to break so the tertiary structure changes shape and no ES complexes form
What is a negative feedback loop?
when self-regulatory mechanisms return internal environment to optimum when there is a fluctuation
What is a positive feedback loop?
when a fluctuation triggers changes that result in an even greater deviation from the normal level
How does a negative feedback loop work?
1) receptors detect deviation
2) coordinator
3) corrective mechanism by effector
4) receptors detect that conditions have returned to normal
Why do separate feedback mechanisms control fluctuations in different directions?
provides more control, especially in the case of ‘overcorrection’, which could lead to a deviation in the opposite direction from the original one
What are 2 reasons why coordinators analyse inputs from several receptors before sending the impulse to effectors?
1) receptors may send conflicting information
2) optimum response may require multiple types of effector
Why is there a time lag between hormone production and response by an effector?
because it takes time to:
- produce hormone
- transport hormone in the blood
- cause required change to the target protein
