Homeostasis basics Flashcards
What is homeostasis?
Involves control systems that keep your internal environment roughly constant
Why do you need to keep your internal environment stable?
To make sure cells can function normally and stop them from being damaged
Why do you need to maintain core body temperature and blood pH?
They affect enzyme activity which control the rate of metabolic reactions
Why do you need to maintain the right concentration of glucose?
Cells need glucose for energy
Affects water potential of blood
Why do you need to maintain temperature?
If body temperature is too high enzymes will become denatured. The enzymes molecules vibrate too much which breaks the hydrogen bonds that hold them in their 3D shape. The shape of the enzyme’s active site is changed and it no longer works as a catalyst. This means the metabolic reactions are less efficient.
If body temperature is too low enzyme activity is reduced slowing the rate of metabolic reactions.
What is the highest temperature that enzymes can work at?
37 degrees
Why do you need to maintain pH?
If blood pH is too low or too high enzymes will become denatured.
What is the optimum pH that most enzymes work best at?
pH 7
Why do you need to maintain blood glucose concentration?
If blood glucose concentration is too high the water potential of the blood is reduced to a point where water molecules diffuse out of cells into the blood by osmosis. This can cause the cells to shrivel up and die.
If blood glucose concentration is too low cells are unable to carry out normal activities as there is not enough glucose for respiration to provide energy
What is negative feedback?
A mechanism that restores levels back to normal
What does negative feedback do?
Negative feedback keeps things around normal levels.
It only works within certain limits
Why does homeostasis involve multiple negative feedback mechanisms?
- more than one mechanism gives more control
- you can actively increase or decrease a level so it returns to normal
What happens if you only have one negative feedback mechanism?
A slower response
Less control
What does positive feedback do?
Amplifies the change
The effectors respond to further increase the level away from the normal level increase
Used to rapidly activate something
