Midterm Flashcards
CNV originates from these 3 sensory nuclei in the midbrain:
mesencephalic, principle sensory, and spinal nuclei
Where do the sensory nuclei merge to form a sensory root?
pons
Where does the sensory root forms the trigeminal or Gasserian ganglion ?
middle cranial fossa, adjacent to the cavernous sinus
Mesencephalic nucleus is in this part of the brainstem:
midbrain
Trigeminal ganglion is in this part of the brainstem:
pons
spinal nucleus is in this part of the brainstem:
medulla
The ophthalmic division exits via:
superior orbital fissure
3 terminal branches of ophthalmic division:
Frontal, Lacrimal, and Nasociliary nerves
What carries postganglionic parasympathetic fibers does CN V carry?
fibers from the pterygopalatine ganglion (via facial nerve) which initially travel with the zygomatic branch of the maxillary division then join the lacrimal branch of the ophthalmic division
CN V innervates:
skin and mucous membrane derivatives of the frontonasal process: Forehead and scalp, Frontal and ethmoid sinuses, Upper eyelid and conjunctiva, Cornea, Dorsum of nose
These nn. supply the back of the head:
cervical
Nerves that supply the ear and neck under mandible:
superficial cervical plexus:
The maxillary division of the trigeminal nerve exits the skull via:
foramen rotundum
The maxillary division gives rise to 14 branches which innervate:
the skin, mucous membranes and sinuses that are derived from the maxillary prominence of the first pharyngeal arch
Does the maxillary division carry para?
Yes, to the lacrimal gland and the nasal glands
7 branches of maxillary division we need to be aware of:
Anterior, Middle and Posterior superior alveolar nerve, Infraorbital nerve, Nasopalatine nerve, Greater and lesser palatine nerves
Mandibular division, sensory or motor?
both
Sensory branches of CNV innervate:
the skin, mucous membranes and striated muscle derivatives of the mandibular prominence of the first pharyngeal arch
4 terminal branches of mandibular division:
Buccal, inf alv (mental nerve/ incisive nerve extension), auriculotemporal, lingual
mandibular division supplies sensory to:
Mucous membranes and floor of the oral cavity, External ear, Lower lip, Chin, Anterior 2/3 of the tongue with special taste sensation from the chorda tympani branch from the facial nerve, All lower teeth, gingiva and bone
Muscles of mastication:
Masseter, Temporalis, Internal/medial pterygoid, External/lateral pterygoid
8 m. pairs innervated by man branch:
mm. of mastication, ant belly of digastric, mylohyoid, tensor veli palatini, tensor tympani
This muscle often caries accessory sensory innervation to mandible:
mylohyoid
Infraorbital block:
Midline thru M2PM including the MB cusp of the Max1M and lip, etc.
Anterior superior alveolar block:
Midline thru canine and lip, etc.
Middle sup alv block:
premolars, MB of 1st molar and later
Pos sup alv block
molars except for the mb root of 1st molar and a little of the buccal gingiva
Nasopalatine block:
only hard palate, triangle that includes canines
Greater palatine block:
one side of hard palate only from the 1st premolar back
Buccal block:
lateral to the molars, no teeth
inf alv block:
entire quadrant except for the mucosa a lip surrounding the molars
incisive block:
midline through premolars and lateral
Nerve supply of ant sup alveolar nerve:
the pulp, investing structures and labial mucoperiosteum of anterior teeth
Middle superior anterior alveolar nerve:
the pulp, investing structures and buccal mucoperiosteum of premolars and MB root of 1st molar
Posterior superior alveolar nerve:
the pulp, investing structures and buccal mucoperiosteum of upper molars except MB root of 1st molar
Greater (anterior) palatine nerve;
palatal mucoperiosteum of maxillary anterior teeth
Closest surrounding structures to where man block is given:
medial pterygoid m., sphenomandibular ligament, medial surface of ramus, lingua nerve
4 ways LA can interfere w excitation:
Alter the resting membrane potential, alter the threshold potential, decrease the rate of depolarization, prolong the rate of repolarization
Action potential generation depends on these ions:
Na, K, Cl, Ca
Primary moa of LA’s:
via specific receptor binding, and inactivation of, the Na channel, sites w/in or around the sodium channel
2 theories as the moa of LA:
membrane swelling and channel blockade theories
In which state do LA’s bind the Na channels?
resting, open, or inactivated
Where does LA act?
w/in the channel itself
snake venom acts here;
outer surface of channel
scorpion venom acts here;
at the fast or slow sodium gates
LA’s are classified by:
site of action
Class A La:
receptor of external surface of membrane
Class B La:
receptor on internal surface of membrane (venoms, not clinically usable)
Class C La:
receptor independent
class D:
combination of receptor dependent and independent mechanisms
Class C La’s exist in this/these form(s)
only uncharged dissociated form
Ex of Class C LA:
benzocaine
Class D La’s exist in this/these form(s):
both the charged, undissociated and the uncharged dissociated forms
Which form is responsible for most activity of the LA?
uncharged: 90%, charged: 10%, RNH+ vs. RN
On what nerve channels can LA act?
only with sodium channels that are not insulated by myelin, only found in abundance at nodes of Ranvier
Nerve channels per square micrometer of small, unmyelinated nerves:
35
Sodium channels per square micromter at nodes of Ranvier:
20,000
of adjacent nodes LA must block in order to work:
at least 3, up to 8-10mm
Primary action of LA in terms of ion control
decrease permeability of sodium channel, slight decrease in K conductance (insignifiicant)
Role of Ca in AP production:
Ca bound in the membrane is thought to have regularoty effect on the movement of Na ions across membrane
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MOA
