Flow Down Gradient Flashcards
Flow is measured by the ________________ that moves over ________.
amount of substance, over time
What is the driving force for the flow of a substance?
energy gradient between point A and point B
The amount of flow is directly related to the size of the ___________ between A and B
energy gradient
The greater the gradient, the (greater/lesser) the flow.
greater
______________ pressure causes gas or liquid to flow from point A to B.
Hydrostatic
Physical structures (resist/encourage) flow.
resist
True or false.
The viscosity of the fluid impacts flow.
True
F = (P1 โ P2) ยท (๐
๐^๐)/๐๐๐
What law is this and what does it determine?
Poiseuilleโs law. Rate of flow
(PL)
F= ___________
Flow. The volume of liquid that passes through a tube per unit time. (i.e L/min)
(PL)
P= _____________
hydrostatic pressure. The force that a substance exerts on the walls of its container
(PL)
r=__________
radius of the tube that the fluid is moving through
(PL)
l = _____________
length of the tube
(PL)
๐ = _____________
viscosity of the fluid
(PL) When hydrostatic pressure and radius increase, flow (increases/decreases)?
increases
(PL) When length of tube and viscosity of fluid increase, flow (increases/decreases)?
decreases
(PL)Which law does the bodyโs control of flow through vessels by: controlling pressure in large vessels and radius of small vessels relate to?
Poiseuilleโs law
(PL)What happens to the resistance if the radius decreases by half?
The resistance increases by a factor of 16 when the radius decreases by half.
(PL)As tubes become more branched or irregularly-shaped, its harder to quantify what?
resistance
(PL)If flow becomes turbulent, the resistance will (change as well/remain the same)?
change as well
(PL)If a tube is flexible - like an artery - Poiseuilleโs law is (more accurate/ not exact)
Not exact
(PL)What is the most important determinant of resistance?
radius of the tube
(FL)Movement of a solute or a gas in a gas mixture from an area of high concentration to low concentration is known as what?
diffustion
___________ law quantifies how the rate of diffusion is affected by various parameters.
Fickโs law
What are the parameters in Fickโs law that quantify the rate of diffusion?
Flow=flux (amount of solute moving across a barrier per unit of time
Force driving flux โ> concentration gradient (C2-C1) difference in concentration on either side of the membrane
resistance: membrane surface area and thickness. Permeability of the membrane to the substance
๐ญ=๐ โ (๐จ(๐ช_(๐จ )โ๐ช_(๐ฉ )) )/๐
What law is this?
Fickโs law
(FL)
F=________
Flow/flux
Number of molecules of a substance diffusing from A to B over time
(FL)
(CA-CB) = _______
Concentration gradient. Difference in concentration on either side of the membrane
(FL)
A=___________
Surface area of the membrane
(FL)
k=a constant that increases when: (2)
1.) the substance is a smaller molecule that dissolves better in the barrier
2.) the permeability of the barrier to the substance increases`
(FL)
t= ____________
thickness of the membrane
(FL)
Flow (increases/decreases) when concentration gradient increases.
increases
Flow (increases/decreases) when surface area increases.
increases
Flow (increases/decreases) when thickness of the membrane increases.
decreases
Flow (increases/decreases) when the substance is a smaller molecule that dissolves better in the barrier.
increases
Flow (increases/decreases) when the permeability of the barrier to the substance increases.
increases
Which systems/locations in the body are affected by Fickโs Law?
Solutes through capillaries
Substances through cell membranes
Oxygen and CO2 from alveolus to blood
(FL)
Membranes have channels or transporters in order to increase __________ of the membrane.
permeability
The need for channels/transporters depends on the __________ of the substance in the membrane.
solubility
Diffusion__________ is a common theme in disease
failure
_________ law relates to the rate of flow of charges across a membrane, which is known as _________.
Ohmโs law
current (I)
๐ผ= ๐/๐
Equation for what law?
Ohmโs law
(OL)
I= _________
Current.
(OH)
V=________
voltage
(OL)
R= ________
resistance
(OL)
_______ is the number of charges or charged particles that move across the membrane per unit of time.
Current
___________ is the energy generated by separating charges across the cell membrane.
Voltage
_____________ is the electrical property of a component or material that impedes the flow of electric current
resistance
(OL)
Current (increases/decreases) when voltage increases.
increases
(OL)
Current (increases/decreases) when resistance increases.
decreases
In Ohmโs law, do opposites attract, and like charges repel?
Yes
What is responsible for establishing voltage?
Electric field of the the charged particle.
(OL)
The particles move (down/up) a gradient of voltage according to their charge.
down
In biology, which law is most useful when thinking about unequal distributions of charges very close on either side of a membrane?
Ohmโs law
True or false.
Overall positive and negative charges are balanced in all physiologic compartments.
True
The electric field (increases/declines) very rapidly as charges are separated by distance.
declines
True or false. Is all situations in physiology, there is only one force that acts on a substance at a time.
False. There are many situations in physiology where more than one force acts on the same substance
The purpose of a ___________ is to transport substances to and from tissues.
capillaries
๐น๐๐ข๐ฅ=([(โ๐๐๐๐ ๐ ๐ข๐๐ ๐น๐๐๐๐๐ โ)โ(โ๐ท๐๐๐๐ข๐ ๐๐๐ ๐น๐๐๐๐๐ โ)])/(โ๐ ๐๐ ๐๐ ๐ก๐๐๐๐ ๐ก๐ ๐ป2๐ ๐๐๐ข๐ฅโ)
๐ ๐ฅ๐ฎ๐ฑ = ๐๐ฉ[ (๐๐๐๐ฉโ๐๐๐๐ )โ๐(๐๐๐๐ฉโ๐๐๐๐ )]
What equation is this?
Starling forces
(SF)
Lp=__________
the โleakinessโ of the capillary wall to water (inverse of resistance)
(SF)
P= __________
Hydrostatic pressure
(SF)
๐ = ________
osmotic pressure
(SF)
โcapโ= _______
fluid within the capilllary
(SF)
โISFโ=_______
fluid within the interstitial space
(SF)
๐=____________
how much protein leaks through the capillary wall
True or False.
Starling forces are easy to measure experimentally.
False. They are difficult to measure because the value of the variables in different situations and in different locations is the subject of much debate
Flux vs. flow?
Flux= flow along a defined membrane surface area
Starling forces can describe tissue (swelling/bleeding) in a wide variety of situations.
Swelling.
Inflammmation/infection.
Changes in pressure within the circulation
_________particles can move across a membrane based on electrostatic forces
charged
CHARGED=ELECTROSTATIC FORCES
____________ particles can move across a membrane based on their concentration gradient
Energy โpoweringโ
Dissolved
DISSOLVED=CONCENTRATION GRADIENT
Which equation tells us:
Diffusional forces and electrical fields are very small at large distances
(Distribution of ions very close to either side of the membrane)
The charge of the particle
The ratio of the particleโs concentration intracellular: extracellular
Nernst potential
What does the Nernst potential NOT include?
The flow of ions (current)
The resistance of the membranes to flow
๐ธ๐= ((โ60๐๐))/๐๐ ๐๐๐10 [๐]๐/[๐]๐
What equation is this?
Nernst potential
(NP)
Ep= __________
The membrane voltage at which a particle (P) moves in and our of the cell at the same rate (EQUALIBRIUM)
(NP)
Zp=__________
The charge and valence of P (anions are negative)
(NP)
[๐]๐/[๐]๐ =____________
ratio of intracellular: extracellular concentrations a P
Nernst potential describes the ________ across a membrane that is permeable to P given the ratio of ____________
voltage
of [P] inside: outside
Because living cells always have a membrane potential that is established by selective transporters and channels, it is helpful to understand what?
Nernst potential
What functions (3) do the charge and ion balance serve?
1.) cellular signaling
2.) transport of substances
3.) regulation of cell volume
A neuron relies on an inside-(negative/positve) membrane potential for the purposes of signaling
negative
The membrane potential is about______ mV in many neurons
-75
The Nernst potential for potassium is close to _____mV
-90
