Homeostasis Flashcards
What does Homeostasis mean?
Maintaining a stable internal environment
State the different stages that trigger a response
Stimulus, Receptors, Control Centre, Effector, Response
What are the two types of feedback mechanisms?
Negative Feedback Loops
Positive Feedback Loops
What is Negative Feedback?
A change in the level of an internal factor causes effectors to restore the internal environment to its original level.
What is Positive Feedback?
A change in the level of an internal factor causes effectors to amplify the change. Causes further change in the same direction.
How can Organisms gain heat?
Production of heat by the metabolism of food during respiration.
Gain of heat from the environment by either conduction, convection or radiation.
How can Organisms lose heat?
Evaporation of water (e.g. sweating).
Loss of heat to the environment through conduction, convection or radiation.
What are Ectotherms?
Bask in sun to increase temperature (Reptiles)
What are Endotherms?
Mammals
What is Vasoconstriction?
Arterioles near surface of skin constrict
Reduces amount of blood reaching skin surface
What are ways the body can keep warm?
- Vasoconstriction
- Shivering
- Raising hair
- Increased metabolic rate
What are the ways the body can cool down?
- Vasodilation
- Increased sweating
- Body hair lies flat
What is Vasodilation?
- Arterioles near skin dilate
- Allows warm blood to pass closer to skin’s surface through capillaries
What is the controlling system?
Hypothalamus within brain
Nervous System
Autonomic Nervous System
What is Hyperthermia?
Long exposure to high temperatures
