Homeostasis Flashcards
What is homeostasis?
Maintenance of a stable internal environment
What is the problem of body temperature being too high?
Enzymes become denatured. Enzyme’s molecules vibrate too much, which breaks the hydrogen bonds that hold their 3D shape. Active site changes so it is not complementary to substrate anymore so doesn’t act as a catalyst.
What is the problem of body temperature being too low?
Enzyme activity reduced, less kinetic energy, slowing rate of metabolic rate.
What is the problem of pH being to high or too low?
Enzymes become denatured, hydrogen bonds broken so active site of enzyme is changed so doesn’t act as a catalyst. Metabolic reactions are less efficient. Optimum: pH7
What is the problem of blood glucose concentration being too high?
Water potential reduced forcing water to diffuse out of cells by osmosis causing cells to shrivel up and die.
What is the problem of blood glucose concentration being too low?
Less glucose available for respiration to provide energy.
What is a negative feedback mechanism?
Detect a change from the optimum and respond by bringing the level back to normal.
What is the disadvantage of having a single negative feedback mechanism for one factor being controlled?
One negative feedback mechanism means you can only turn it on and off. You could change a level in one direction so it returns to normal. It’s like trying to slow down in a car with only the accelerator, all you can do is take your foot of the accelerator to slow down. More negative feedback mechanisms give more control
What is a positive feedback mechanism and give an example?
Amplify a change from the normal level so it’s further away from the normal line. Example: Hypothermia: as body temperature falls the brain doesn’t work properly and shivering stops - this makes temperature fall even more.
Name a factor that increases blood glucose concentration.
Eating food containing carbohydrates.
Name a factor that decreases the blood glucose concentration.
Exercise: more glucose used to make energy in respiration.
Where is insulin secreted from?
Beta cells
Where is glucagon secreted from?
Alpha cells
What is insulin?
A hormone that lowers blood glucose concentration when it’s too high.
What is glucagon?
A hormone that raises the blood glucose levels when it’s too low.