L4 Innervation

Question 1

Innervation can either be _____ or ____.

Answer 1

Afferent or efferent

Question 2

The nerves that provide efferent innervation are:

Answer 2

CN V, VII, IX, X, XII

Question 3

What are the motor functions of CN V?

Answer 3

Innervates the muscles of mastication and the floor of the mouth

Question 4

What are the motor functions of CN VII?

Answer 4

Innervates the muscles of the lips, which is a sphincter

Question 5

What are the motor functions of CN IX?

Answer 5

Innervates pharyngeal constrictors and stylopharyngeus

Question 6

What are the motor functions of CN X?

Answer 6

Serves palate, pharynx, larynx, esophagus

Question 7

What are the motor functions of CN XII?

Answer 7

Innervates tongue

Question 8

The nerves that provide afferent innervation are:

Answer 8

CN V, CN VII, CN IX, CN X

Question 9

CN ____ provides general sensation to the anterior 2/3 of the tongue while CN ____ provides taste to this area.

Answer 9

V

VII

Question 10

CN ____ provides taste and sensation to the posterior 1/3 of the tongue.

Answer 10

IX

Question 11

What is the sensory role of CN X?

Answer 11

Sensation of mucosa of valleculae

Question 12

What are the 3 major components of neural control?

Answer 12

Cerebral fibers
Brainstem nuclei
Afferent/efferent fibers

Question 13

The cerebral fibers are comprised of:

Answer 13

Afferent fibers, efferent fibers, integrating areas

Question 14

The brainstem nuclei are comprised of:

Answer 14

Sensory nuclei, motor nuclei, interneuron nuclei

Question 15

The afferent/efferent fibers are comprised of:

Answer 15

Peripheral afferent/efferent nerves

Question 16

Sensory information is sent to ________ while motor information is sent to ___________.

Answer 16

The postcentral gyrus

The precentral gyrus

Question 17

Name the four integration areas and their functions.

Answer 17

Insula – site of sensorimotor integration
Internal capsule – pathway for ascending and descending fibers
Pars triangularis – representation of taste
Gustatory area – sensation of taste

Question 18

Where is the pars triangularis located?

Answer 18

Frontal operculum, in the inferior frontal gyrus

Question 19

The cortical and subcortical sites involved in the pharyngeal phase of swallowing include:

Answer 19

Primary and secondary sensorimotor cortices, insula, anterior and posterior cingulate cortices, basal ganglia, amygdala, hypothalamus, substantia nigra

Question 20

True/False

The cortical and subcortical regions involved in swallowing form the infratentorium.

Answer 20

False – supratentorium

Question 21

Neuronal influences on swallowing are either ___ or ____.

Answer 21

Excitatory, inhibitory

Question 22

The ______ and _______ exhibit excitatory control on swallowing via dopaminergic mechanisms.

Answer 22

Amygdala, lateral hypothalamus

Question 23

The _______ and ________ inhibit swallowing.

Answer 23

Periaqueductal grey, ventrolateral pontine reticular formation

Question 24

Why is swallowing inhibition important?

Answer 24

In the oral preparation and oral transport phases, it prevents the premature trigger of the pharyngeal swallow.

Question 25

Where do fibers from the cranial nerves and cerebral centres synapse, and what are this region’s roles?

Answer 25

Brainstem nuclei in reticular formation (roughly in pons) – regulates alertness, fatigue, motivation, sleeping, eating

Question 26

True/False | You only need one intact swallowing centre for swallowing to occur.

Answer 26

True

Question 27

True/False | Visceral input, like respiratory information, is sent to the swallowing centre.

Answer 27

True

Question 28

The infratentorium is comprised mainly of:

Answer 28

The medulla

Question 29

The central pattern generator within the _______ helps control the _________ and _______ phases of swallowing.

Answer 29

medulla, Pharyngeal, esophageal

Question 30

What are CPGs?

Answer 30

Neuronal pools that contain sensory, motor and interneurons that work together to control sequential, rhythmic and somatic events within the body. Functions independently of sensory feedback.

Question 31

True/False | Neurons in the CPG fire superiorally to inferiorally

Answer 31

False – rostral to caudal

Question 32

True/False | CPGs have unilateral representation in the medulla.

Answer 32

False – bilateral

Question 33

What are the motor neurons that are involved in the swallowing CPG?

Answer 33

CN V, VII, XII motor nuclei Nucleus ambiguus (CN IX, X) Dorsal motor nucleus (CN X) C1, C3 (cervical spinal neurons)

Question 34

The main motor nuclei involved in swallowing are ______ and _______.

Answer 34

CN XII motor nucleus and nucleus ambiguus

Question 35

The motor output for the smooth muscle of the lower esophagus is provided by __________

Answer 35

Dorsal motor nucleus

Question 36

The sensory neurons that regulate the pharyngeal and esophageal phases of swallowing in the brainstem include ______________ and _____________.

Answer 36

Nucleus tractus solitarius, reticular formation

Question 37

CN ___ sends sensory information from the oral, pharyngeal and esophageal mucosa, as well as taste sensation from the epiglottis, to the nucleus tractus solitarius and the reticular formation in the brainstem.

Answer 37

X

Question 38

What sensory input does CN V send to the brainstem?

Answer 38

General sensation of oral mucosa, anterior 2/3 of tongue

Question 39

What sensory input does CN VII send to the brainstem?

Answer 39

Taste to anterior 2/3 of tongue

Question 40

What sensory input does CN IX send to the brainstem?

Answer 40

General sensation of oropharynx and posterior 1/3 of tongue, taste from posterior 1/3 of tongue

Question 41

List the trigger regions of the pharyngeal phase.

Answer 41

Posterior faucial pillars, pharyngeal wall, base of tongue, oropharyngeal mucosa, electrical stimulation of superior laryngeal nerve

Question 42

With regards to the CPG, “generator neurons” are in the ________ and “switching neurons” are in the _______.

Answer 42

Nucleus tractus solitarius | Reticular formation

Question 43

Dorsal sensory and ventral motor signals are integrated within the swallowing CPG via the following 2 groups of interneurons:

Answer 43

Dorsal swallowing group | Ventral swallowing group

Question 44

After sensory information is sent to the nucleus tractus solitarius and reticular formation, interneurons in the ______ are activated.

Answer 44

Dorsal swallowing group

Question 45

The dorsal swallowing group sends motor signals to the _________.

Answer 45

Ventral swallowing group

Question 46

The ventral swallowing group passes sequenced, coordinated motor signals to the ____________ and _________ (as well as the motor trigeminal nucleus and facial motor nucleus).

Answer 46

Hypoglossal motor nucleus, nucleus ambiguus