Section 2 Flashcards
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
What is the neuroanatomy of the Sypathetic system?
thoracolumbar
What is the neroanatomy of the parasympathetic system?
craniosacral
What organs have only sympathetic innervation?
adrenal medulla, peripheral blood vessels, pilomotor muscles, and sweat glands
For the sympathetic nervous system are the preganglionic fibers long or short?
short (opposite for Parasymp) and postganglionic fibers
What second neurons use ACh as the NT?
- Cardiac and smooth muscle, gland cells, nerve terminals (Parasymp.)
- Sweat glands (Sympathetic) = symp. cholinergic
- Somatic skeletal muscle
What second neurons use NE as the NT? (released from the adrenal medulla)
Cardiac smooth muscle, gland cells, nerve terminals (Sympathetic)
What second neurons use Dopamine as the NT?
Renal vascular smooth muscle (sympathetic)
What does COMT do?
inactivates metabolites
What drug inhibits VMAT (transports NE back into vessicle)?
Reserpine
What drug inhibits Tyr –> Dopa? (tyrosine hydroxylase)
Metyrosine
What is the name of the transporter that recycles NE back into the pre-synaptic cell?
NET
What inhibits NET?
Cocaine, tricyclic antidepressants & amphetamines
What inhibits fusion of the vessicle to the end of the pre-synaptic cell?
Bretylium, guanethidine
