Section 2 Flashcards
(37 cards)
How does Intracrine signaling work?
Signaling within the cell. The signal never leaves the cell.
What is the delivery pathway for the signal in endocrine and neuroendocrine chemical signaling?
The bloodstream
What is the RMP?
Resting Membrane Potential = -50 to -70mV
At rest, neurons are permeable to what?
K+ (potassium)
At rest, how does K+ get into the cell?
voltage-INDEPENDENT “leak” K+ channels
What is the current defined by?
the direction in which positive charge flows (aka Convention)
Which way does K+ and Na+ move during a current?
Na+ = in & K+ = out
Intracellular K+
140
Intracellular Na+
15
Intracellular Cl-
30
Intracellular Ca2+
0.0001
Extracellular K+
5
Extracellular Na+
145
Extracellular Cl-
110
Extracellular Ca2+
2
What equation is like the Nernst equation but takes into account the relative permeabilites?
Goldman Equation
How many K+ are pumped for every Na+?
2K+ for every 3Na+
What is happening during the rising phase of an action potential?
Na+ influx inward (fast depolarization)
What is happening during the falling phase of an action potential?
K+ efflux outward (repolarization)
What happens up stream of an action potential?
- Na+ channels are inactivated
2. K+ channels open
What happens to the action potential when tetrodotoxin is brought into the picture?
action potential is inhibited
What triggers synaptic neurotransmitter release by promoting protein interaction and fusion of NT vesicle and the presynaptic membrane?
calcium
What kind of synapse allow direct coupling between presynaptic and postsynaptic membranes via gap junctions?
Electrical synapse (found in heart muscle)
What is the NT that is always between the 1st and 2nd neuron?
ACh