B9.4 and B9.5 - Homeostasis and Tropic Responses Flashcards
What is homeostasis?
The maintenance of a constant internal environment.
What is negative feedback?
The mechanism for how homeostasis works.
A change that sets of a response that cancels the change.
Why does body temperature need to be controlled?
To maintain optimum enzyme activity.
Why does our blood glucose concentration need to be controlled?
To keep the blood/tissue fluid isotonic to the cells to prevent osmosis and the bursting or shrinking of our cells.
Why does our water concentration need to be controlled?
To keep the blood/tissue fluid isotonic to the cells to prevent osmosis and the bursting or shrinking of our cells.
What are the steps of negative feedback. [4]
- Deviation from the norm (above or below)
- Detected by receptors
- Effectors stimulated and initiate corrective mechanisms
- Restoration of the norm
Where does blood glucose come from?
Starch/carbs that you’ve eaten and digested.
When is the hormone insulin released?
When the level of blood glucose is too high.
Where is insulin released from?
Pancreas.
What does insulin do?
It allows the liver to turn excess glucose into glycogen.
What happens if the blood glucose level drops too low?
Glucagon is released.
What does glucagon do?
Makes the liver turn glycogen back into glucose.
What are the three mechanisms to reduce body temperature?
- Hairs lie flat.
- Sweating.
- Vasodilation.
What are the four mechanisms to increase body temperature?
- Hairs stand up
- Much less sweat
- Shivering
- Vasoconstriction
What happens in vasodilation?
- Shunt vessel narrows
- Arterioles widen/dilate
- Capillaries widen/dilate
-More blood flows through the capillaries in the surface of the skin - More heat is lost by radiation and conduction
