Term
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Definition
Transport of Small Molecules and Ions
Generation of the Transmembrane Resting and Action Potentials |
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Term
| co2, oxygen, small polar molecules, and ethanol all easily go across membrane. co2 is even more soluble than oxygen. |
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Definition
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Term
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Definition
No Carrier
Not Regulated Physiologically, Exception: Permeability to Water of Renal Tubule and Collecting Duct
Energy Source
Concentration Gradient for Non-charged Molecules
Electrochemical Potential Gradient for Ions
Rate Determined by Electrochemical Potential Gradient and Membrane Permeability |
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Term
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Definition
| rate at which a substance moves across a membrane, proportional to permeablity |
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Term
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Definition
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Term
| if you see an electrochemical gradient vs. flux chart, the line with the steeper slope is the more permeable substance |
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Definition
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Term
| some physiological processes depend on diffusion, list some: |
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Definition
- gas exchange in lungs and between blood and tissue
- transport of lipid soluble substances across membranes
- movement of molecules and ions in the intracellular and extracellular space |
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Term
| facilitated diffusion DOES NOT use atp |
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Definition
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Term
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Definition
Carrier or Channel-Mediated
Specific
Regulated Physiologically
Energy Source - Electrochemical Potential Gradient / Concentration Gradient
Rate Determined by Electrochemical Potential Gradient and Carrier or Channel Kinetics |
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Term
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Definition
- number of carriers
- carrier kinetics |
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Term
| initial slope on a vmax curve is a function of: |
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Definition
- affinity of the substance for the carrier
- concentration gradient (but vmax does not depend on concentration gradient) |
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Term
| list three important characteristics about channels: |
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Definition
- specific
- gated
- controlled by voltage or chemical
also either all the way open or all the way closed |
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Term
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Definition
Aquaporins facilitate diffusion of water across membranes.
In most membranes, the number of aquaporins is so large that water crosses the membrane faster than dissolved solutes. This prevents significant osmotic pressure across most cell membranes.
The number of aquaporins in the cell membrane can be regulated. |
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Term
| for osmotic presure, the ___ __ ___ , not the ___ is important. |
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Definition
- number of particles
- not the mass |
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Term
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Definition
| osmoles of solute per liter solution |
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Term
| normal body osmolarity is |
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Definition
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Term
| solutions that do not change cell size are : |
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Definition
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Term
| solutions that cause cell size to increase are called: |
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Definition
| - hypotonic solutions- cause cell size to increase b/c they are less concentrated than the cells, so water has to rush into the cells to balance out the osmotic pressure |
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Term
| solutions that cause cells to shrivel are called: |
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Definition
| - hypertonic- cause cells to shrivel b/c solution is more concentrated than cell is, so water has to leave cell and go into solution |
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Term
| primary active transport: |
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Definition
Carrier-Mediated
Specific
Physiologically Regulated
Transport Against Electrochemical Gradient / Concentration Gradient
Energy Source - ATP
Rate Determined by 1) Electrochemical Gradient, 2) Carrier Kinetics, 3) ATP |
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Term
| to check blood osmolarity use centrifuge and check hematocrit= percentage of blood that is cells, should be about 40 |
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Definition
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Term
| primary active transport energy source is ___, but secondary active transport energy source is ___ ___ |
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Definition
ATP
electrochemical gradient of driving process |
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Term
| examples of secondary active transport: |
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Definition
- sodium moving into cell going down concentratin gradient, brings glucose along against its gradient= symport
- as sodium enters cell H+ leaves cell (antiport) |
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Term
| calcium and hydrogen extrusion are driven by the sodium electrochemical gradient. explain: |
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Definition
- sodium calcium secondary active transport antiport
- sodium moves down its concentratin gradient into the cell and calcium is expelled
- also have a sodium hyrodgen secondary active transport antiport |
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Term
| anesthesia works b/c gas readily diffuses across lungs and cell membranes |
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Definition
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Term
| what processes are important for absorption of glucose in intestinal lumen, epxlain: |
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Definition
- Na+/K+ atpase active transport- needed to maintain electrochemical gradient
- Na+/glucose secondary active transport contransport of glucose with sodium down its concentration gradient
- faciliated diffusion: of glucose on basolateral domain, out of lumen and into blood |
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Term
| important passive transporters: |
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Definition
- Na+ channel- allows sodium to enter cell going down its concentration gradeint
- K+ channel- allows potassium to leave cell going down its concentration gradient
- glucose uniporter- allows glucose to follow its concentration gradient |
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Term
| explain secondary active transport of calcium: |
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Definition
| - three sodiums are being pumped into the cell going down their concentration gradient, calcium gets pumped out |
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Term
| cell membrane normally more permeable to ___ than ___ |
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Definition
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Term
| contributers to negative inside of cell: |
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Definition
The Na+ - K+ transporter decreases intracellular Na+ while increasing intracellular K+
The cell membrane is normally more permeable to K+ than to Na+
As the intracellular K+ concentration increases, K+ flows outward more readily than Na+ flows inward, making the inside negative
The cell membrane is impermeable to large, negatively charged substances
In the steady state, K+ efflux, down a small electrochemical gradient through high permeability equals Na+ influx down a large electrochemical gradient through low permeability, so the transmembrane potential is stable at a negative value |
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Term
| nernst equation computes the ___ ___ for a ___ ion |
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Definition
- equillibrium potential
- specific |
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Term
| at the equillibrium potential, the ____ ___ ___ exactly balances an ___ ____ ___ ___. the chemical potential is due to the transmembrane concentration difference. |
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Definition
- transmembrane electrical potential
- opposing transmembrane chemical potential |
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Term
| so sodium has a concentration gradient that favors its entry into the cell, the equillibrium potential tells you the exact ___ ___ that must be reached to counteract the concentration potential. |
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Definition
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Term
| so if equiliibrium potent for potassium is -93 mV and the cell is at -70, then potassium is going to leak out. but the inside of the cell with regards to potassium isn't this negative so have to have active transport to keep potassium in. |
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Definition
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Term
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Definition
ease at which ions flow through a membrane
when conductance is high, permeability is high |
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Term
| so with action potential thre is a rapid but short lived incrase in sodium conductance. potassium conductance rises more slowly but stays longer |
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Definition
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