Week 3 Terms Flashcards
What are 3 properties of Ion channels?
1) They recognize and select specific ions
2) They open and close in response to electrical, mechanical, or chemical signals
3) They conduct ions across the membrane
Oxygen has a ___ charge
Negative
Hydrogen has a ___ charge
Positive
Cations
Positively charged ions
Anions
Negatively charged ions
What is Ohm’s law?
i = V/ R
i = current through the channel
V= voltage across membrane
R=resistance of the open channel
What are the 3 major classes of ion channels?
1) Voltage gated
2) Ligand-gated
3) Mechanically gated
What is the term for when the current reaches a point it can no longer increase in concentration?
Saturate
Dissociation constant
the concentration at which half of the channels will be occupied by a bound ion
What are the 3 Gating Mechanisms?
1) Chemical Ligands
2) Membrane Potential
3) Mechanical Stretch
What are the 3 functional states of channels?
1) Resting (closed, but activatable)
2) Active (open)
3) Refractory (closed)
What is equilibrium potential?
when the net flux between the electrostatic force and force of diffusion is zero
What is the Graded Potential?
Change in potential of the membrane around the ion channel (can be positive or negative)
Spatial Summation
based on the location of inputs around the dendrites & cell body (the sum of their inputs can trigger action potential)
Temporal Summation
based on timing of triggers from synaptic inputs
