22 - lecture Flashcards
Which of the following blocking agents would have the most rapid and significant effect on the resting membrane potential in a typical neuron?
K Channel blocker
What creates a membrane potential?
Charge seperation - only allowing a positive or a negative pass the membrane
What is required for a resting membrane potential?
semi-permeable membrane, concentration gradient that is driven by Na/K ATPase, and selective channels (pathway for charged ions to flow across)
Monovalent cation?
Na+, K+
Bivalent cation?
Ca2+
Monovalent anion?
Cl-
Na+ mV?
+60
K+ mV?
-83
Ca2+ mV?
+129
Cl- mV?
-66
What plays the biggest role in setting the membrane potential?
The ion with the the largest conductance
Where do Neurons get their information?
Dendrites and the cell body
What mV is the resting potential at? and why is it established?
-70mV. Established because of Na and K+ leak channels, Na/K pumps, chemical/electrical gradients
What happens at -55mV?
This point is called the Threshold….Depolarization: The Na voltage gated channels open up and Na rushes into the cell.
What happens at 30mV?
Repolarization: The K voltage gated channels open up and K rushes in.
How many mOsm are in 1 mM NaCl?
2 mOsm
What does not affect the osmotic pressure exerted by a solute in solution?
The molecular weight.
What is the reaction coefficient if the membrane is impermeable and if permeable?
Impermeable - 1
Permeable - 0
What are examples of penetrating solutes?
Glucose, Glycerol, Urea
What are examples of non-penetrating solutes?
Sucrose, NaCl, KCl
150 mM NaCl + 50 mM glycerol
Hyper-osmotic
Isotonic
150 mM NaCl + 300 mM urea
Hyper-osmotic
Isotonic
300 mM Urea
Iso-osmotic
Hypotonic
