Homeostasis Flashcards
What is homeostasis?
The tendency to maintain a stable, relatively constant internal environment.
What organs maintain homeostasis and pathways of homeostatic control?
Nervous system (through hypothalamus)
Endocrine system is controlled by nervous system
Autonomic nervous system ‘
liver, pancreas, kidneys
What are the main components of a homeostatic controlled system and their functions?
Stimulus - a signal, such as a chemical or physical cue generated inside of the body, or outside of the body like ambient temperature or duration and intensity of light.
Receptor - the sensing component that monitors and responds to internal or external changes
Control centre - includes an integrator that compares signals detected by the sensor to the set point for the variable to be regulated. (compensate for change in variable)
Effector - the target acted on to bring about the change back to the normal state of the set point.
What is a positive feedback loop?
a change in intensity of a stimulus causes further changes on the same stimulus. The variable under control has the ability to amplify itself, thus in a positive feedback loop the stimulatory signal target a tissue and the product of the target tissue leads to an increase in the intensity of the response.
What is a negative feedback loop?
a change in intensity of a stimulus causes inhibition of the same stimulus. Negative feedback loop occurs when a stimulatory signal targets a tissue, and the product of the target tissue leads to a decrease in the intensity of a response to a stimulatory signal. In this way, a negative feedback loop brings a system closer to stability.
