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Antero-posteriorly, the greater palatine foramen is located between the
___________________________.
middle oft he maxillary second molar and the middle of the third
molar in about 80-90% of patients.
all arteries leading to the oral cavity receive blood from what?
external carotid (most are direct or indirect branches from the
maxillary artery with the exception of the lingula -- this is a direct
branch from the external
carotid)
veins from the oral cavity will drain into what?
internal jugular (both internal and external drain into the
brachiocephalic veins which drain to the superior vena cava
do myelinated or un-myelinated nerves create faster impulse?
myelinated (impulses jump from node to node -- node of ranvier)
,what is saltatory conduction?
the process of nerve impulses jumping from nodes of ranvier along a
myelinated nerve
what is the resting potential charges of a nerve?
inside is negative and outside is positive
what molecules are predominately outside/inside at resting potential?
Na+ outside and K+ inside
what is depolarization?
Na+ channels open , Na+ flows in reversing polarity; K+ flows out to
restore neutrality; the Na+ and K+ pumps restore polarity (resting
potential)
what is the mechanism of action for local anesthetics?
blocks the Na+ channels preventing depolarization
what is the basic structure of anesthetics?
aromatic ring (lipid soluble), intermediate chain (amide or ester
configuration), and terminal amine (able to ionize and become water
soluble)
, lipophilic vs. hydrophyllic
lipophilic is lipid soluble and hydrophyllic is water soluble
what makes the terminal amine so important to the structure of local
anesthetic?
this allows the local anesthetic to the both lipid soluble and water
soluble at the apporpriate times (ex: hydrophyllic for dilution and pH
control; lipophyllic in
order to penetrate neuron cell membrane; hydrophyllic to block Na+
channels)
what is pKa and what does it do?
the dissociation constant - this identifies the pH at which the anesthetic
exists in a 50/50 ratio of the ionized to non-ionized (hydrophyllic to
lipophyllic) molecules
lipid solubility of local anesthetics
the different structure of the various anesthetics confers varying
degrees of lipid solubility (the greater the lipid solubility of the basic
molecule the more potent it is)
protein binding of local anesthetics
the greater degree of protein binding, the more molecules you have
waiting in reserve for later action (the more proteins bound, the longer
the duration)