5.1.1 The Principles Of Homeostasis Flashcards
What does the body do instead as it can’t maintain the same environment inside for ever?
It maintains a dynamic equilibrium with small fluctuations over a narrow range of conditions - homeostasis
How are receptors and effectors vital in homeostasis
They are key in maintaining a dynamic equilibrium. Sensory receptors detect changes in the internal and external environment, which is necessary to ensure that things such as blood pH or body temp remain at a stable rate. This information from the sensory receptors is transmitted to the brain and impulses get sent along motor neurones to effectors to bring about changes to restore the equilibrium
What are effectors
They are muscles or glands that react to the motor stimulus to bring about a change in response to a stimulus. Both effectors and receptors are vital in maintaining homeostasis - detecting change is no use without the means to react to that change
What does homeostasis depend on
Sensory receptors detecting very small changes in the body and the effectors working to restore and equalise these changes. These mechanisms are based upon feedback systems that enable the maintenance of a relatively steady state around a narrow range of conditions
What are negative feedback systems
Most of the feedback systems we have are negative feedback. If a change goes one direction, the body’s effectors will work to reverse it and restore conditions to their base level. Examples include the control of blood sugar, temperature control and water balance
What are positive feedback systems?
There are very few in the body. In these positive feedback systems, a change in the internal environment is detected by receptors and effectors are stimulated to reinforce that change and increase the response. An example being the blood clotting cascade. When vessel damaged, platelets stuck to the damaged region and they releases factors that initiate clotting and attract more platelets. These additional platelets also attract more platelets. This continues until clot is formed p.
What is another example of positive feedback
Childbirth - head presses against cervix stimulating oxytocin production, this stimulates uterus to contract, pushing the head of the baby even harder against the cervix and triggering the release of more oxytocin. Continues until baby born
