Y2 ocr homeostasis. Flashcards
what is homeostasis?
The maintenance of dynamic equilibrium over a narrow range of conditions.
what kind of systems does the body use to monitor and respond to the changes from the steady state of the body?
electrical and chemical
give some examples of some conditions in the body that need to be maintained w/in narrow range?
- blood glucose concentration
- sodium ions in the blood (ie solute conc)
- pH and water balance of the bodu fluids
- the core temp of the body.
why is it impossible to maintain a living mammal in a completely stable state?
bc everything causes minute changes.
instead the body manages a “dynamic equilibrium”
what is the function of sensory receptors?
Sensory receptors detect changes in the internal and external environment of an organ isms.
give some examples of receptors and what they detect?
photoreceptors detect changes in light
chemoreceptors detect changes in chemicals (ie pH)
thermoreceptors in the SKIN detect changes in external temperature
mechanoreceptor detects changes in pressure
where is the information from the sensory receptor transmitted to?
the brain and impulses are then sent along motor neurones to the EFFECTORS (which bring about change)
what is the function of the effectors?
Effectors are muscles and glands that work to react to the motor stimulus and bring about a RESPONSE
what are the 2 main effectors ?
Muscles and glands.
How do the effectors, Muscles,bring about a response to stimuli?
muscles
- squeeze the gut
- squeeze chemicals from glands
- contract
How do the effectors, glands bring about a response to a stimuli?
glands secrete enzymes and hormones into the blood stream.
why are both receptors and effectors important in homeostasis?
- the body needs sensory receptors to monitor changes in the internal environment
- effectors respond to the changes , restoring them back to normal levels
what are the 2 main feedback systems?
negative and positive feedback
what is meant by the term negative feedback system?
A negative feedback system is one that works to reverse the changes brought on by a stimulus. It Aims to reverse the system back to normal level and to nullify and INHIBIT the effect of the change.
What is meant by a positive feedback system?
A system that works to increase (amplify ) the effect of the change brought on by a stimulus. It brings the system further away from normal base level.