Intro to cranial nerves Part A

Question 1

Cranial nerves are part of what system?

they come from the

Answer 1

PNS

brain/brain stem

Question 2

nerves vs. neurons

Answer 2

nerve- bundle of neurons that can be multifunctional or all the same function (it can have some neurons that are visceral afferent, some that are visceral efferent, some are somatic afferent, some could be somatic efferent, or all could be the same)

neuron= individual nerve cells where each neuron can only have a single modality –either sensory or motor

Question 3

Cranial Nerves- Somatics

With Cranial nerves, instead of going to the spinal cord, they connect up with the ______

Can be _____ or _______

Somatic Motor innervates
Somatic Sensory does

Answer 3

brain

motor
sensory

skeletal muscles

sensations coming back from somatic tissues

Question 4

sensory ganglion

Answer 4

you have a sensory ganglion that is always located outside of the CNS –in spinal nerves this is the DRG, in cranial nerves this is the “sensory ganglia”

Question 5

Cranial Nerves- Visceral

simp & parasympathetic?

Answer 5

only does parasympathetic (cranial/sacral)
ex: this could be smooth muscle in eyes/eye lid, lacrimal glands, salivary glands

because symp= thoracolumbar and we are out of that region (when we are in the head and neck)

Question 6

Special modalities are only found in the:

2 different kinds of special modalities:

Answer 6

head/neck/cranial nerves

1) Special senses- oflaction, taste, vision hearing, balance
2) Special “visceral” efferent (SVE)—special because they come from a different source embryologically than other muscles in the body. They coming from branchiomeric mm. during embryonic development

Question 7

Where are most muscles in the body derived from?

Answer 7

somites

Question 8

special Subset of muscles in head/neck is derived from

Answer 8

pharyngeal arches AKA branchial arches

Question 9

Each pharyngeal arch is: (3 things)

Answer 9

1) Associated with a particular cranial nerve
2) Develops a set of skeletal mm. (“branchiomeric mm.”)
3) Develops a set of skeletal elements

Question 10

Pharyngeal Arch I
CN
Branchiomeric mm
Skeletal derivatives

Answer 10

CN V= trigeminal
mm= mm of mastication:
-tensor tympani
-tensor veli palatini
-mylohyoid
-ant. belly digastric 

skeletal derivs= malleus, incus, sphenomandibular ligament (mockers’ cartilage)

Question 11

Pharyngeal Arch II
CN
Branchiomeric mm
Skeletal derivatives

Answer 11

CN VII= facial
mm= mm of facial expression
stapedius
stylohyoid
post. belly of digastric

skeletal derivs= stapes, styloid process, stylohyoid ligament, lesser horn, and superior body of hyoid

Question 12

Pharyngeal Arch III
CN
Branchiomeric mm
Skeletal derivatives

Answer 12

CN IX= glossopharyngeal

mm= stylopharyngeus

skeletal derivs= greater horn and inferior body of hyoid

Question 13

Pharyngeal Arch IV & VI
(there is no V)
CN
Branchiomeric mm
Skeletal derivatives

Answer 13

CN X= vagus
mm= most parietal mm
most pharyngeal mm
all laryngeal mm

skeletal derivs= laryngeal cartilages

Question 14

For head and neck part of course, if something is sensory (general sensation) doesn’t matter if its somatic or visceral—we just call it a

If it is a special sensory, we call it by e

Answer 14

sensory nerve

what it is—ex: olfaction, vision, hearing, balanc