Dr. Stevens - Transporters, channels, voltage and concentration Flashcards
What is the concentration of electrolytes in the cell?
Na+ and Cl- outside the cell
K+ and A- inside the cell
What is the normal osmolarity of Na+ outside the cell?
145 mEq/L
What is the normal osmolarity if K+ inside the cell?
120 mEq/L
What is the normal osmolarity of Cl- in the ECF?
105 mEq/L
What is the primary contributor of the electrical gradient across the cell membrane?
K+ leakage back across the cell membrane from the gradient created by Na+ / K+ pump.
Where are AA anions (-) most prevalent?
Outside the cell in the cytoplasm.
What are the components of the cell membrane?
lipid bilayer
cholesterol
proteins
lipids
What are the two general ways that ions
passively without any kind of transporter
by way of a transporter
Of membrane transporter what are the catagories?
Channels
Transporters
How is a channel different than a transporter?
Channels are just proteins that allows ions and water to flow with the concentration gradient.
What two types of transporters?
Solute Carrier and Pumps
What is the key characteristics of pumps?
They use ATP to pump against gradient.
What is a secondary active transport?
They use the concentration gradient created by a pump to move another ion / molecule against the concentration gradient without ATP.
What are the characteristics of passive diffusion?
Goes with concentration gradient.
small polar molecules pass through
Large polar and ions don’t
What are the types of channels? against / with gradient?
- Ligand-Gated
- Voltage-Gated
- Leak
- Stretch-Activated
It moves things with concentration gradient.
Solute Carriers do?
The use a concentration gradient created with a Na/K ATPase pump to move other molecules (glucose) against the concentration gradient without ATP.
What are the purposes of primary active transporters?
Maintain bioelectrical gradient
Provide gradient for secondary active transport
pump electrolytes
Create solute concentrations that support osmosis
What is the pump leak model?
That leaking via a channel and pumping via and ATPase happen simultaneously but separatly.
How is cell membrane potential maintained?
degree of ion permeability and ion concentration.
What is the physiology of metabolic acidosis hyperkalemia?
High H+ concentration in the ECF leads to a slient exchange across the membrane with K+ as H+ flows in and K+ flows out. This is clinically represented as hyperkalemia.
Why does Rhabdomyolysis cause cardiac arrest?
The muscle cell crush causes a flood of K+ into the ECF. This initial hyperkalemia results in an influx of K+ into the cell and the resulting depolarization of the cell. This can cause caridac arrest by depolarization.
