Homeostasis Flashcards
What is homeostasis
The act of maintaining a relatively constant internal environment in which all processes work optimally
Why is it important to maintain constancy of internal environment
To ensure that processes can occur at their optimum conditions to ensure efficiency and effectiveness. Otherwise cells would not function and the body would suffer
How are organ systems involved in homeostasis
Work together and integrate to maintain optimum internal environment within body for cells to function and produce energy
What systems coordinate other systems
Endocrine and nervous
Equation of life
O2 plus nutrients leads to CO2 plus waste materials
What is negative feedback control
A signal is sent to correct the disturbance that posed a threat to homeostasis and brings the condition back within the normal range eg drinking to increase water levels on a hot day due to thirst pathways being stimulated
Characteristics of negative feedback
Oscillation around a set point, restores the regulated condition after disturbance but cannot prevent it
Feed forward systems
Receptors anticipate change and activate response system eg kidneys concentrating urine to preserve water
Positive feedback control
Lead to greater disturbance eg in action potential rapid depolarisation of cell due to increase in sodium ions increases sodium permeability within cell
Associated with pathology more than physiology eg diabetes
Water is found in what compartments
Plasma, interstitial fluid, intracellular fluid
Why is the composition of the extra cellular fluid so important
The body can only survive as long as the composition of the extra cellular fluid is maintained in a state compatible with the survival if it’s individual cells
Water is distributed in what way between each compartment
1/3 extra cellular, 2/3 intracellular fluid
What is the dilution principle
V= m/c
What compartments can be measured directly using the dilution principle
Plasma, extracellular fluid, total body water
What is crucial in determining the test substance in body fluid measurements
The nature of barriers
