homeostasis principles Flashcards
define homeostasis
Homeostasis is the ability to control the internal environment
why is homeostasis important
This allows the cells to experience constant conditions and function optimally
Explain the importance of homeostasis with particular reference to temperature and blood pH
Enzymes and proteins are sensitive to fluctuations in pH and temperature,
They reduce in activity or are denatured in not optimal conditions
Maintaining a constant pH and temperature mean reactions take place at a suitable rate.
what is the role of tissue fluid in homeostasis
Cells are surrounded by tissue fluid which is regulated to maintain an environment that fluctuates around an optimum point for factors such as water potential, temperature and pH.
Give and describe the stages to a control mechanism
Optimum point: point at which the system works best.
Monitored by…
Receptor: detects deviation from optimum (ie stimulus).
Coordinator: coordinates information from receptors and sends information to…
Effector: muscle or gland that brings about changes to return system to optimum point.
Return to normality creates a …
Feedback mechanism: by which a receptor responds to a stimulus created by the change to the system brought about by the receptor
give the 2 ways control mechanisms are coordinated
positive feedback
negative feedback
define positive feedback
Positive feedback - deviation from optimum causes changes that result in further deviation from optimum. Small stimulus leads to large response
define negative feedback
Negative feedback - the change produced by the control system leads to a change that turns the system off and reduces deviation from the optimum
Define negative feedback
Negative feedback occurs when the stimulus turns off the corrective measures and returns system to optimum level (avoiding overshoots)
Explain how negative feedback helps to control homeostatic processes
Negative feedback has two separate mechanisms to regulate deviation from the optimum
(one in each direction). Receptor detects deviation from optimum ,
information from receptors is coordinated and instruction given to an effector to bring about a response to return to optimum,
negative feedback mechanism detects this change and brings about appropriate response
Explain how negative feedback mechanisms give a greater degree of control
The separate mechanisms to regulate deviation in either direction allow greater control because they are positive actions in both directions (rather than just allowing something to naturally return to normal)
Distinguish between negative feedback and positive feedback
Negative feedback causes corrective measures to be switched off when optimum has been restored whereas in positive feedback the corrective mechanism remains turned on and further deviation from optimum occurs.
