The Principles Of Homeostasis Flashcards
why is it impossible to maintain a living mammal in a completely stable state?
everything causes minute changes.
what is homeostasis?
when the body maintains a dynamic equilibrium, with small fluctuations over a narrow range of conditions.
what are vital for the body to maintain homeostasis?
receptors and effectors.
what is the role of sensory receptors?
detect changes in the internal and external environment of an organism
what are some of the internal factors of an organism that must be monitored?
- pH of the blood
- core body temperature
- concentrations of urea and sodium ions in the blood.
how is equilibrium restored in the body?
information from the sensory receptors is transmitted to the brain and impulses are sent along the motor neurones to the effectors to bring about changes to restore the equilibrium in the body.
what are effectors?
muscle or glandsthat react to the motor stimulus to bring about a change in response to a stimulus.
why is it important to have effectors and receptors?
effectors are important as detecting change is no use without the means to react. receptors are important as effectors cause chaos unless responding to a need.
what is a negative feedback system?
a feedback system that works to reverse the initial stimulus.
is negative feedback or positive feedback more common in the body?
negative feedback.
what are some examples of a negative feedback system?
- control of blood sugar levels by insulin and glucagon.
- temperature control of the body.
- water balance of the body
what is a positive feedback system?
a type of feedback system which reinforces the stimulus and increases the response.
what are some examples of positive feedback?
- the blood clotting cascade.
- mechanism seen during childbirth.
how is the blood clotting cascade an example of positive feedback?
when a blood vessel is damaged, platelets stick to the damaged region and release factors that initiate clotting and attract more platelets.
