CH 6 - Signal Transduction Flashcards
(40 cards)
T/F: The larger the concentration gradient, the larger the equilibrium potential because a larger, electrically-driven movement of ions will be required to balance the movement due to the concentration difference.
true
T/F: Action and graded potentials are only on the membranes.
True
What is the position of optimal influence for an axon terminal on the soma/cell body and WHY?
Optimal influence would be closest to the axon hillock because there’s less room for decremental spread.
What is plasticity?
The ability for the brain to modify its structure and function.
What is the relationship between voltage summation magnitude on the axon hillock and frequency of action potentials?
The higher the voltage on the axon hillock, the higher the frequency of action potentials up until you’ve reached your absolute refractory period.
What is an example of something that exceeds the 3:2 ratio of Na/K with the Na/K ATPase pump?
An action potential, leaky K+ channels on the axon.
What are the two key variables/components in the Nernst equation?
- Charge
- Concentration differences across a membrane
How do the two components in the Nernst equation relate to its purpose?
Charge and concentration determine voltage, and voltage determines the ability for the cell to do work.
Ligand and mechanically gated channels trigger ____ while voltage gated channels prompt ____
Graded potentials; action potentials
How does the number of neurotransmitters (NTs)/ligands on a postsynaptic cell relate to the amplitude of voltage change?
Depends on whether these NTs/ligands stimulate an IPSP or an EPSP.
Why will all action potentials have the same amplitude regardless of stimulus strength?
Because once threshold is reached, membrane events are no longer dependent on the strength of the stimulus.
Why are refractory periods important?
They ensure discrete action potentials and one way propagation.
Why is a larger stimulus needed during the relative refractory period for another action potential?
Some of the K+ channels that repolarized the membrane are still open, opposing depolarization.
Describe the process of Ca+ at the terminal axon when it receives an action potential.
Ca+ flows into the axon terminal, binds to synaptotagomins, triggers SNARE protein change, and causes neurotransmitter release.
What is the importance of myelin?
Myelin enhances induction velocity.
What makes myelin in the CNS and PNS?
- Oligodendrocytes in the CNS
- Schwann cells in the PNS
What is resting membrane potential?
-70 mV
What would it mean if resting membrane potential was 0 mV?
There would be no concentration gradient.
What dictates the maximum frequency of an action potential along a neuron?
The raided potential amplitude.
What is the GHK equation?
It takes into account individual ion permeabilities.
What is sodium’s charge and where is its concentration higher?
Sodium is positively charged and has a higher concentration outside the cell.
What will sodium’s graded potential look like?
Sodium would enter the cell and the graded potential would depolarize.
What is potassium’s charge and where is its concentration higher?
Potassium is positively charged and has a higher concentration inside the cell.
What will potassium’s graded potential look like?
Potassium would leave the cell and the graded potential would polarize.
