L1 HOMEOSTASIS Flashcards
What is homeostasis?
The dynamic maintenance of a relatively constant
internal environment, to create optimal functioning
for the body.
Why is homeostasis vital for normal body function?
Homeostasis allows organisms to exists in external
environments that demonstrate wide changes.
Allows greater levels of independence/flexibility
Explain homeostasis in terms of a dynamic process?
Homeostasis is dynamic not static, there are fluctuations in the mechanisms utilized in the controlling of systems. (physiological variable).
Describes an optimal set of conditions under which cells function best.
What mechanism does the body use to maintain homeostasis?
The body uses autoregulation to maintain homeostasis.
What is autoregulation?
Example?
Autoregulation is the adaptive response of internal biological systems to automatically respond to specific changes in the external environment.
E.g. key organs in the body(brain, heart, kidney)-regulating blood vessel diameter
What is Extrinsic regulation?
Extrinsic regulation involves the central systems and involves the use of the nervous and endocrine systems.
Key structure: hypothalamus
Monitor changes in parameters and then institute processes to counteract changes.
What is Negative Feedback?
The response of the body systems that are in opposition to the environment’s changes.
What are disadvantages of negative feedback?
3
- The response can be too large (over correction)
- A large change = a large response. (amount of correction determined by magnitude of error signal)
- The change must first happen for a response to be generated. It does not predict changes(anticipatory).
Describe the model of negative feedback?
Set point, comparator, error signal, controller, controlled system, controlled variable and sensor.
What are mechanisms to overcome the disadvantages of negative feedback?
Example?
Having multiple functioning controlled systems accommodates the disadvantages of negative feedback.
e.g blood sugar regulation
What is gain?
Gain is a measure of effectiveness of feedback system.
What is positive feedback?
Positive feedback movement in direction of environmental change.
Benefits of positive feedback?
Large change in a fast time is an advantage of positive feedback.
What is the formula for gain?
Define each term?
Gain= correction/ error.
Correction is calculated by the normal value- the response value (feedback value).
Error is calculated by the change value - response value (feedback value). Error is always negative.
What is an example of positive feedback?
- Labour
2. Blood Clotting
