Principles of Homeostasis 15.1 Flashcards
What kind of conditions are regulated for enzyme controlled reactions?
In order for enzyme-controlled reactions to take place, the temperature, pH, concentration of glucose and sodium ions and the water balance must be kept within a narrow range
Can organisms maintain a completely stable state?
It is impossible to maintain a completely stable state as there will always be tiny fluctuations all the time.
What is homeostasis?
This is the state in which the body is kept when it is stable. It is in dynamic equilibrium with small fluctuations happening over a narrow range of conditions. It is the optimum state for enzyme controlled reactions to take place
How does the body detect changes and what does it do?
A change will be detected by sensory receptors and this information will be sent past the sensory, relay and finally motor neurones where they will reach the effectors. The effectors are muscles or glands that will respond to the stimulus and return the body to homeostasis
What is negative feedback?
It is a system in which a change has been detected in one direction and effectors will work to reverse this change and restore conditions to their base levels (homeostasis)
Give examples of negative feedback
Your core body temperature increases. This is detected by sensory receptors and the effectors will produce a response to lower your body temperatures back to optimum temp
What is positive feedback?
This is when a change is detected by the sensory receptors and the effectors will produce a response that reinforces this change, so the conditions will change.
Give 2 examples of positive feedback
- When a blood vessel is damaged, platelets will release factors that attract more platelets and they will also come and contribute to the positive feedback cycle until a blood clot is formed
- When giving birth and the baby head is at the cervix, oxytocin is released which makes the uterus contract more, so pushes the baby further down and this continues until the baby is out
