Homeostasis Flashcards
What is the difference between equilibrium and steady state? Which one is most prevalent in physiological processes?
Equilibrium is no net flow, no energy gradients, etc. Steady state is when inputs = outputs. Steady state is what happens in the body.
Name the four basic components of a homeostatic control mechanism.
- Sensor
- Transmission pathways
- Control center
- Effector(s)
What is the difference between positive and negative feedback?
Positive feedback accelerates a process towards a climax and negative feedback restores an altered output to a set range.
What percentage of body weight is body water?
55-60%
Intracellular fluid makes up _____% of total body water and extracellular fluid makes up _____% of total body water.
Intracellular is 65-70%
Extracellular is 30-35%
What two compartments make up extracellular fluid and what are their respective percentages?
Plasma is 20-25% of the ECF and interstitial fluid is 75-80% of the ECF.
Name two examples of transcellular fluid.
Cerebrospinal fluid and synovial joint fluid.
Na+ and Cl- are in high concentrations in the _____, while K+ is high in the _____.
Na+, Cl- high in extracellular fluid, K+ is high in the intracellular fluid.
Describe the charge effect of plasma proteins.
Plasma proteins occupy 7% of plasma volume and carry a net negative charge. The negative charge therefore repels anions back into the interstitium and pulls cations out of the interstitium for electroneutrality. So the plasma has increased concentration of cations compared to the interstitium and decreased concentrations of anions compared to the interstitium.
Charge vs. volume effects for anions are _______.
additive
What is the net effect of charge and volume effects on cations?
They cancel out
What is the equation for thermal regulation?
M (metabolic heat production) ± R (radiation) ± C (convection) - E (evaporation) = 0
