Homeostasis Flashcards
What is the definition of homeostasis?
The process by which the body prevents disturbance and maintains an optimum internal environment
What needs to work cooperatively in homeostasis?
Organ systems, coordinated by the nervous and endocrine system
What needs to be maintained for a constant internal environment?
ECF (80% IF and 20% plasma)
What is -ve feedback control?
Self-limitation
What is the process of -ve feedback control?
- Receptors detect a temperature change
- Signal is sent to an integrating centre
- Signal is compared to a reference level
- If there is a change then the signal is sent to an effector
- The effector nullifies the change
What is the magnitude of the error single in -ve feedback control proportional to?
The size of the response and its deviation
What is +ve feedback control systems?
Self-amplifcation, the opposite of -ve feedback
What is the process of +ve feedback control systems?
Initial disturbance sets off a chain reaction that leads to greater instability
Where do +ve feedback control occur?
Action potentials and ovulation
What is feed-forward control?
A more advanced version of -ve feedback control
What is the process of feed-forward control?
The anticipation of change before they occur
What is an example of feed-forward control?
The skin anticipating changes in temperature before core temperature is affected
What happens when water is lost?
Water is gained
How is water lost?
Urine
How is water gained?
Thirst mechanism
How is the ration of ICF to ECF?
ICF- 2/3
ECF- 1/3
What does ECF consist of?
Plasma and interstitial fluid
What is the barrier that separates the Interstitial fluid and plasma?
Capillary wall, which is permeable to everything but plasma proteins (too big)
What is the barrier that separates the interstitial fluid and the extracellular fluid?
Cell membrane, which has a selective permeability in which ions can’t pass freely
How are body fluid compartments measured?
If they contain plasma (PV)
How can volume be calculated indirectly?
ICF=TBW-ECF
What is diabetes?
Lack of insulin, causing the liver to produce too much glucose into the blood stream causing elevated BG levels which leads to uncontrolled hyperglycaemia
What is the cause of diabetes?
Breakdown of homeostatic regulation
