Homeostasis And Control Systems Flashcards
What is the definition of physiology?
The study of the physical and chemical basis of life processes, with a special emphasis on how these processes are integrated in cells, tissues, organs, organ systems and the whole organism
What is steady-state?
Under normal conditions, the time-averaged value of chemical and physical variables is maintained fairly constant
How do disturbances affect steady-state?
They can result in a new steady state
Failure to re-establish stead-state equilibrium can result in?
Death
What is control volume?
An arbitrary value in which the mass of the continuum remains constant
What is the relationship between steady-state and control volume?
At steady-state, energy within the control volume is also constant
What is the driving force of chemical reactions?
Concentration
What would happen if you increase the concentration of a chemical reaction?
More frequent collisions and an increased rate of reaction
What is the driving force of passive diffusion?
Concentration
What impacts passive diffusion?
Membrane parameters and membrane permeability
What would cause an increase in flux during passive diffusion + reaction?
Substrate reacting away
Why are facilitated diffusion and active transport necessary?
For movement of large solutes and movement against currents
What is convection?
The movement of liquid
What is the driving force of convection?
Pressure gradient
What are purely hydrostatic pressure driven systems dependent on?
Permeability of the vessel
What is convection + solvent drag?
Solutes in the ultra-filtrate that are transported back by the flow of water rather than specifically by ion pumps or other membrane transport proteins
How is the flow of an ionic current determined?
Force x conductance
What is fluid sheer force dependent on?
Viscosity
How can a compression force be calculated?
How much it deforms/how much pressure
What is hoop stress?
Force on vessel due to pressure
What are some examples of negative feedback control?
Temperature, blood pressure and blood sugar
What are some examples of positive feedback control?
Platelet activation, inflammation
What is feed forward control?
The system anticipates change in a controlled variable before it occurs by monitoring changes in the external environment
What are some examples of feed forward control?
Salivating before eating, excitement before a race
What are some characteristics of control systems?
They can be variable and adaptive. Components and complexity are determined by control volume or system
What is proportional negative feedback?
Responds to change
What is integral negative feedback?
Compensation for the past to elongate residual error
What is derivative negative feedback?
Anticipatory control/dampening
T/F: Substrate concentration is always the rate limiting factor for michaelis-menten kinetics.
False
T/F: In the venous system, the colloid osmotic pressure is greater than that of hydraulic pressure.
True
What is required for reputake of water into the blood vasculature after ultrafiltration in the kidneys?
High colloid osmotic pressure and low hydraulic pressure in the blood vasculature
T/F: The net movement of fluids between the arterial vasculature and the interstitial fluid is towards the inside of the blood vessel
False
T/F: The lower the gain of the system, the more efficient it is at maintaining homeostasis
False
What is hydraulic (hydrostatic) pressure?
The force of the fluid volume against a membrane
