Dynamic and Steady State Conditions

Question 1

What is the relationship between the amounts of a substance taken into the body, produced in the body, and eliminated from the body under steady state conditions?

Answer 1

input + what body makes = eliminate

*A system is in steady state with respect to the levels of a substance when
Input of the substance + Production of the substance = Elimination of the substance.
If this condition is met, the total amount of the substance in the system remains at a constant level.

Question 2

How will the concentration or amount of a substance in the body change over time in the case where the rate at which that substance is added to the body (taken in or produced) increases, assuming all else is held constant?

Answer 2

concentration increases

Question 3

How will the concentration or amount of a substance in the body change over time in the case where the rate at which that substance is eliminated from the body decreases, assuming all else is held constant?

Answer 3

concentration increases

Question 4

Why might tracking the amount or concentration of a substance in the body over time allow you to deduce changes in the input, production, or elimination of that substance?

Answer 4

it gives you a sense of what could be happening to somebody bc steady state is changing

Question 5

what is ohms law?

Answer 5

change in pressure= flow x resistance

ex of tank with drainpipe the water fills tank and the pressure increases
the pressure is equal to change in P1-P2 in drainage pipe
flow is related to the difference in pressure between the inside of the orifice and the outside of the orifice, it is feasible that as the height of the water decreases, the difference in pressure, and thus the flow, decreases until a new steady state is reached

Question 6

For the analogy of a tank with a drainpipe, what would be the change in the fluid level over time (relative to the initial fluid level) in the case where the rate of fluid being added is suddenly increased to be a constant rate that is higher than the rate at which fluid is draining?

Answer 6

the fluid level would be rising and potentially spill over the drainpipe because the rate of draining can not keep up

height of water rises (dynamic state) then reestablishes back to a steady-state

Question 7

What is the relationship between partial pressure of carbon dioxide in the venous circulation (PvCO2), partial pressure of carbon dioxide in the arterial circulation (PaCO2), and elimination of carbon dioxide via the lungs under normal conditions?

Answer 7

partial pressure of C02 in venous circulation is about 45 mm mercury (from muscles/tissue producing the CO2 diffusing into the blood)

CO2 unloads a little diffuses across to air sac to be breathed out

partial pressure in arterial blood is about 40 mm mercury

• Carbon dioxide produced in the muscle tissue travels in the venous blood and is offloaded in the alveolus, and is subsequently breathed off. The blood then flows from the alveolar capillary into the arterial system with a lower carbon dioxide content than was in the venous blood.

Question 8

What would happen to arterial and venous PCO2 values over time after airflow to/from one lung is blocked?

Answer 8

now thereis reduced ability to eliminate CO2 but body is still producing the same amount - this throws steady state

the CO2 in venous (45) stays same to the arterial flow (couldnt unload) this travels around body and picks up more CO2 which keeps going and accumulating CO2

the PCO2 that is leaving the normal lung now rises bc it is only one working
* so CO2 will rise in blood to the point where diffusion gradient is so big that it is able to unload CO2 and get into a new steady state condition - eliminitating now = to what is produced

** High diffusion gradient, reachieving a new steady state a higher level of CO2